1. 14 May, 2020 1 commit
    • Niklas Schnelle's avatar
      s390/pci: Fix s390_mmio_read/write with MIO · f058599e
      Niklas Schnelle authored
      The s390_mmio_read/write syscalls are currently broken when running with
      MIO.
      
      The new pcistb_mio/pcstg_mio/pcilg_mio instructions are executed
      similiarly to normal load/store instructions and do address translation
      in the current address space. That means inside the kernel they are
      aware of mappings into kernel address space while outside the kernel
      they use user space mappings (usually created through mmap'ing a PCI
      device file).
      
      Now when existing user space applications use the s390_pci_mmio_write
      and s390_pci_mmio_read syscalls, they pass I/O addresses that are mapped
      into user space so as to be usable with the new instructions without
      needing a syscall. Accessing these addresses with the old instructions
      as done currently leads to a kernel panic.
      
      Also, for such a user space mapping there may not exist an equivalent
      kernel space mapping which means we can't just use the new instructions
      in kernel space.
      
      Instead of replicating user mappings in the kernel which then might
      collide with other mappings, we can conceptually execute the new
      instructions as if executed by the user space application using the
      secondary address space. This even allows us to directly store to the
      user pointer without the need for copy_to/from_user().
      
      Cc: stable@vger.kernel.org
      Fixes: 71ba41c9 ("s390/pci: provide support for MIO instructions")
      Signed-off-by: default avatarNiklas Schnelle <schnelle@linux.ibm.com>
      Reviewed-by: default avatarSven Schnelle <svens@linux.ibm.com>
      Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
      f058599e
  2. 10 May, 2020 7 commits
    • Linus Torvalds's avatar
      Linux 5.7-rc5 · 2ef96a5b
      Linus Torvalds authored
      2ef96a5b
    • Linus Torvalds's avatar
      Merge tag 'x86-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · c14cab26
      Linus Torvalds authored
      Pull x86 fixes from Thomas Gleixner:
       "A set of fixes for x86:
      
         - Ensure that direct mapping alias is always flushed when changing
           page attributes. The optimization for small ranges failed to do so
           when the virtual address was in the vmalloc or module space.
      
         - Unbreak the trace event registration for syscalls without arguments
           caused by the refactoring of the SYSCALL_DEFINE0() macro.
      
         - Move the printk in the TSC deadline timer code to a place where it
           is guaranteed to only be called once during boot and cannot be
           rearmed by clearing warn_once after boot. If it's invoked post boot
           then lockdep rightfully complains about a potential deadlock as the
           calling context is different.
      
         - A series of fixes for objtool and the ORC unwinder addressing
           variety of small issues:
      
             - Stack offset tracking for indirect CFAs in objtool ignored
               subsequent pushs and pops
      
             - Repair the unwind hints in the register clearing entry ASM code
      
             - Make the unwinding in the low level exit to usermode code stop
               after switching to the trampoline stack. The unwind hint is no
               longer valid and the ORC unwinder emits a warning as it can't
               find the registers anymore.
      
             - Fix unwind hints in switch_to_asm() and rewind_stack_do_exit()
               which caused objtool to generate bogus ORC data.
      
             - Prevent unwinder warnings when dumping the stack of a
               non-current task as there is no way to be sure about the
               validity because the dumped stack can be a moving target.
      
             - Make the ORC unwinder behave the same way as the frame pointer
               unwinder when dumping an inactive tasks stack and do not skip
               the first frame.
      
             - Prevent ORC unwinding before ORC data has been initialized
      
             - Immediately terminate unwinding when a unknown ORC entry type
               is found.
      
             - Prevent premature stop of the unwinder caused by IRET frames.
      
             - Fix another infinite loop in objtool caused by a negative
               offset which was not catched.
      
             - Address a few build warnings in the ORC unwinder and add
               missing static/ro_after_init annotations"
      
      * tag 'x86-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        x86/unwind/orc: Move ORC sorting variables under !CONFIG_MODULES
        x86/apic: Move TSC deadline timer debug printk
        ftrace/x86: Fix trace event registration for syscalls without arguments
        x86/mm/cpa: Flush direct map alias during cpa
        objtool: Fix infinite loop in for_offset_range()
        x86/unwind/orc: Fix premature unwind stoppage due to IRET frames
        x86/unwind/orc: Fix error path for bad ORC entry type
        x86/unwind/orc: Prevent unwinding before ORC initialization
        x86/unwind/orc: Don't skip the first frame for inactive tasks
        x86/unwind: Prevent false warnings for non-current tasks
        x86/unwind/orc: Convert global variables to static
        x86/entry/64: Fix unwind hints in rewind_stack_do_exit()
        x86/entry/64: Fix unwind hints in __switch_to_asm()
        x86/entry/64: Fix unwind hints in kernel exit path
        x86/entry/64: Fix unwind hints in register clearing code
        objtool: Fix stack offset tracking for indirect CFAs
      c14cab26
    • Linus Torvalds's avatar
      Merge tag 'objtool-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · 8b000832
      Linus Torvalds authored
      Pull objtool fix from Thomas Gleixner:
       "A single fix for objtool to prevent an infinite loop in the
        jump table search which can be triggered when building the
        kernel with '-ffunction-sections'"
      
      * tag 'objtool-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        objtool: Fix infinite loop in find_jump_table()
      8b000832
    • Linus Torvalds's avatar
      Merge tag 'locking-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · bd2049f8
      Linus Torvalds authored
      Pull locking fix from Thomas Gleixner:
       "A single fix for the fallout of the recent futex uacess rework.
      
        With those changes GCC9 fails to analyze arch_futex_atomic_op_inuser()
        correctly and emits a 'maybe unitialized' warning. While we usually
        ignore compiler stupidity the conditional store is pointless anyway
        because the correct case has to store. For the fault case the extra
        store does no harm"
      
      * tag 'locking-urgent-2020-05-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
        ARM: futex: Address build warning
      bd2049f8
    • Linus Torvalds's avatar
      Merge tag 'iommu-fixes-v5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu · 27d2dcb1
      Linus Torvalds authored
      Pull iommu fixes from Joerg Roedel:
      
       - Race condition fixes for the AMD IOMMU driver.
      
         These are five patches fixing two race conditions around
         increase_address_space(). The first race condition was around the
         non-atomic update of the domain page-table root pointer and the
         variable containing the page-table depth (called mode). This is fixed
         now be merging page-table root and mode into one 64-bit field which
         is read/written atomically.
      
         The second race condition was around updating the page-table root
         pointer and making it public before the hardware caches were flushed.
         This could cause addresses to be mapped and returned to drivers which
         are not reachable by IOMMU hardware yet, causing IO page-faults. This
         is fixed too by adding the necessary flushes before a new page-table
         root is published.
      
         Related to the race condition fixes these patches also add a missing
         domain_flush_complete() barrier to update_domain() and a fix to bail
         out of the loop which tries to increase the address space when the
         call to increase_address_space() fails.
      
         Qian was able to trigger the race conditions under high load and
         memory pressure within a few days of testing. He confirmed that he
         has seen no issues anymore with the fixes included here.
      
       - Fix for a list-handling bug in the VirtIO IOMMU driver.
      
      * tag 'iommu-fixes-v5.7-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
        iommu/virtio: Reverse arguments to list_add
        iommu/amd: Do not flush Device Table in iommu_map_page()
        iommu/amd: Update Device Table in increase_address_space()
        iommu/amd: Call domain_flush_complete() in update_domain()
        iommu/amd: Do not loop forever when trying to increase address space
        iommu/amd: Fix race in increase_address_space()/fetch_pte()
      27d2dcb1
    • Linus Torvalds's avatar
      Merge tag 'block-5.7-2020-05-09' of git://git.kernel.dk/linux-block · 0a85ed6e
      Linus Torvalds authored
      Pull block fixes from Jens Axboe:
      
       - a small series fixing a use-after-free of bdi name (Christoph,Yufen)
      
       - NVMe fix for a regression with the smaller CQ update (Alexey)
      
       - NVMe fix for a hang at namespace scanning error recovery (Sagi)
      
       - fix race with blk-iocost iocg->abs_vdebt updates (Tejun)
      
      * tag 'block-5.7-2020-05-09' of git://git.kernel.dk/linux-block:
        nvme: fix possible hang when ns scanning fails during error recovery
        nvme-pci: fix "slimmer CQ head update"
        bdi: add a ->dev_name field to struct backing_dev_info
        bdi: use bdi_dev_name() to get device name
        bdi: move bdi_dev_name out of line
        vboxsf: don't use the source name in the bdi name
        iocost: protect iocg->abs_vdebt with iocg->waitq.lock
      0a85ed6e
    • Linus Torvalds's avatar
      gcc-10: mark more functions __init to avoid section mismatch warnings · e99332e7
      Linus Torvalds authored
      It seems that for whatever reason, gcc-10 ends up not inlining a couple
      of functions that used to be inlined before.  Even if they only have one
      single callsite - it looks like gcc may have decided that the code was
      unlikely, and not worth inlining.
      
      The code generation difference is harmless, but caused a few new section
      mismatch errors, since the (now no longer inlined) function wasn't in
      the __init section, but called other init functions:
      
         Section mismatch in reference from the function kexec_free_initrd() to the function .init.text:free_initrd_mem()
         Section mismatch in reference from the function tpm2_calc_event_log_size() to the function .init.text:early_memremap()
         Section mismatch in reference from the function tpm2_calc_event_log_size() to the function .init.text:early_memunmap()
      
      So add the appropriate __init annotation to make modpost not complain.
      In both cases there were trivially just a single callsite from another
      __init function.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e99332e7
  3. 09 May, 2020 12 commits
    • Linus Torvalds's avatar
      Merge tag 'riscv-for-linus-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux · 2e28f3b1
      Linus Torvalds authored
      Pull RISC-V fixes from Palmer Dabbelt:
       "A smattering of fixes and cleanups:
      
         - Dead code removal.
      
         - Exporting riscv_cpuid_to_hartid_mask for modules.
      
         - Per-CPU tracking of ISA features.
      
         - Setting max_pfn correctly when probing memory.
      
         - Adding a note to the VDSO so glibc can check the kernel's version
           without a uname().
      
         - A fix to force the bootloader to initialize the boot spin tables,
           which still get used as a fallback when SBI-0.1 is enabled"
      
      * tag 'riscv-for-linus-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
        RISC-V: Remove unused code from STRICT_KERNEL_RWX
        riscv: force __cpu_up_ variables to put in data section
        riscv: add Linux note to vdso
        riscv: set max_pfn to the PFN of the last page
        RISC-V: Remove N-extension related defines
        RISC-V: Add bitmap reprensenting ISA features common across CPUs
        RISC-V: Export riscv_cpuid_to_hartid_mask() API
      2e28f3b1
    • Linus Torvalds's avatar
      gcc-10: avoid shadowing standard library 'free()' in crypto · 1a263ae6
      Linus Torvalds authored
      gcc-10 has started warning about conflicting types for a few new
      built-in functions, particularly 'free()'.
      
      This results in warnings like:
      
         crypto/xts.c:325:13: warning: conflicting types for built-in function ‘free’; expected ‘void(void *)’ [-Wbuiltin-declaration-mismatch]
      
      because the crypto layer had its local freeing functions called
      'free()'.
      
      Gcc-10 is in the wrong here, since that function is marked 'static', and
      thus there is no chance of confusion with any standard library function
      namespace.
      
      But the simplest thing to do is to just use a different name here, and
      avoid this gcc mis-feature.
      
      [ Side note: gcc knowing about 'free()' is in itself not the
        mis-feature: the semantics of 'free()' are special enough that a
        compiler can validly do special things when seeing it.
      
        So the mis-feature here is that gcc thinks that 'free()' is some
        restricted name, and you can't shadow it as a local static function.
      
        Making the special 'free()' semantics be a function attribute rather
        than tied to the name would be the much better model ]
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1a263ae6
    • Linus Torvalds's avatar
      gcc-10: disable 'restrict' warning for now · adc71920
      Linus Torvalds authored
      gcc-10 now warns about passing aliasing pointers to functions that take
      restricted pointers.
      
      That's actually a great warning, and if we ever start using 'restrict'
      in the kernel, it might be quite useful.  But right now we don't, and it
      turns out that the only thing this warns about is an idiom where we have
      declared a few functions to be "printf-like" (which seems to make gcc
      pick up the restricted pointer thing), and then we print to the same
      buffer that we also use as an input.
      
      And people do that as an odd concatenation pattern, with code like this:
      
          #define sysfs_show_gen_prop(buffer, fmt, ...) \
              snprintf(buffer, PAGE_SIZE, "%s"fmt, buffer, __VA_ARGS__)
      
      where we have 'buffer' as both the destination of the final result, and
      as the initial argument.
      
      Yes, it's a bit questionable.  And outside of the kernel, people do have
      standard declarations like
      
          int snprintf( char *restrict buffer, size_t bufsz,
                        const char *restrict format, ... );
      
      where that output buffer is marked as a restrict pointer that cannot
      alias with any other arguments.
      
      But in the context of the kernel, that 'use snprintf() to concatenate to
      the end result' does work, and the pattern shows up in multiple places.
      And we have not marked our own version of snprintf() as taking restrict
      pointers, so the warning is incorrect for now, and gcc picks it up on
      its own.
      
      If we do start using 'restrict' in the kernel (and it might be a good
      idea if people find places where it matters), we'll need to figure out
      how to avoid this issue for snprintf and friends.  But in the meantime,
      this warning is not useful.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      adc71920
    • Linus Torvalds's avatar
      gcc-10: disable 'stringop-overflow' warning for now · 5a76021c
      Linus Torvalds authored
      This is the final array bounds warning removal for gcc-10 for now.
      
      Again, the warning is good, and we should re-enable all these warnings
      when we have converted all the legacy array declaration cases to
      flexible arrays. But in the meantime, it's just noise.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5a76021c
    • Sagi Grimberg's avatar
      nvme: fix possible hang when ns scanning fails during error recovery · 59c7c3ca
      Sagi Grimberg authored
      When the controller is reconnecting, the host fails I/O and admin
      commands as the host cannot reach the controller. ns scanning may
      revalidate namespaces during that period and it is wrong to remove
      namespaces due to these failures as we may hang (see 205da243).
      
      One command that may fail is nvme_identify_ns_descs. Since we return
      success due to having ns identify descriptor list optional, we continue
      to compare ns identifiers in nvme_revalidate_disk, obviously fail and
      return -ENODEV to nvme_validate_ns, which will remove the namespace.
      
      Exactly what we don't want to happen.
      
      Fixes: 22802bf7 ("nvme: Namepace identification descriptor list is optional")
      Tested-by: default avatarAnton Eidelman <anton@lightbitslabs.com>
      Signed-off-by: default avatarSagi Grimberg <sagi@grimberg.me>
      Reviewed-by: default avatarKeith Busch <kbusch@kernel.org>
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      59c7c3ca
    • Alexey Dobriyan's avatar
      nvme-pci: fix "slimmer CQ head update" · a8de6639
      Alexey Dobriyan authored
      Pre-incrementing ->cq_head can't be done in memory because OOB value
      can be observed by another context.
      
      This devalues space savings compared to original code :-\
      
      	$ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux
      	add/remove: 0/0 grow/shrink: 0/4 up/down: 0/-32 (-32)
      	Function                                     old     new   delta
      	nvme_poll_irqdisable                         464     456      -8
      	nvme_poll                                    455     447      -8
      	nvme_irq                                     388     380      -8
      	nvme_dev_disable                             955     947      -8
      
      But the code is minimal now: one read for head, one read for q_depth,
      one increment, one comparison, single instruction phase bit update and
      one write for new head.
      Signed-off-by: default avatarAlexey Dobriyan <adobriyan@gmail.com>
      Reported-by: default avatarJohn Garry <john.garry@huawei.com>
      Tested-by: default avatarJohn Garry <john.garry@huawei.com>
      Fixes: e2a366a4 ("nvme-pci: slimmer CQ head update")
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      a8de6639
    • Christoph Hellwig's avatar
      bdi: add a ->dev_name field to struct backing_dev_info · 6bd87eec
      Christoph Hellwig authored
      Cache a copy of the name for the life time of the backing_dev_info
      structure so that we can reference it even after unregistering.
      
      Fixes: 68f23b89 ("memcg: fix a crash in wb_workfn when a device disappears")
      Reported-by: default avatarYufen Yu <yuyufen@huawei.com>
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarJan Kara <jack@suse.cz>
      Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      6bd87eec
    • Yufen Yu's avatar
      bdi: use bdi_dev_name() to get device name · d51cfc53
      Yufen Yu authored
      Use the common interface bdi_dev_name() to get device name.
      Signed-off-by: default avatarYufen Yu <yuyufen@huawei.com>
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      Reviewed-by: default avatarJan Kara <jack@suse.cz>
      Reviewed-by: default avatarBart Van Assche <bvanassche@acm.org>
      
      Add missing <linux/backing-dev.h> include BFQ
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      d51cfc53
    • Linus Torvalds's avatar
      gcc-10: disable 'array-bounds' warning for now · 44720996
      Linus Torvalds authored
      This is another fine warning, related to the 'zero-length-bounds' one,
      but hitting the same historical code in the kernel.
      
      Because C didn't historically support flexible array members, we have
      code that instead uses a one-sized array, the same way we have cases of
      zero-sized arrays.
      
      The one-sized arrays come from either not wanting to use the gcc
      zero-sized array extension, or from a slight convenience-feature, where
      particularly for strings, the size of the structure now includes the
      allocation for the final NUL character.
      
      So with a "char name[1];" at the end of a structure, you can do things
      like
      
             v = my_malloc(sizeof(struct vendor) + strlen(name));
      
      and avoid the "+1" for the terminator.
      
      Yes, the modern way to do that is with a flexible array, and using
      'offsetof()' instead of 'sizeof()', and adding the "+1" by hand.  That
      also technically gets the size "more correct" in that it avoids any
      alignment (and thus padding) issues, but this is another long-term
      cleanup thing that will not happen for 5.7.
      
      So disable the warning for now, even though it's potentially quite
      useful.  Having a slew of warnings that then hide more urgent new issues
      is not an improvement.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      44720996
    • Linus Torvalds's avatar
      gcc-10: disable 'zero-length-bounds' warning for now · 5c45de21
      Linus Torvalds authored
      This is a fine warning, but we still have a number of zero-length arrays
      in the kernel that come from the traditional gcc extension.  Yes, they
      are getting converted to flexible arrays, but in the meantime the gcc-10
      warning about zero-length bounds is very verbose, and is hiding other
      issues.
      
      I missed one actual build failure because it was hidden among hundreds
      of lines of warning.  Thankfully I caught it on the second go before
      pushing things out, but it convinced me that I really need to disable
      the new warnings for now.
      
      We'll hopefully be all done with our conversion to flexible arrays in
      the not too distant future, and we can then re-enable this warning.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      5c45de21
    • Linus Torvalds's avatar
      Stop the ad-hoc games with -Wno-maybe-initialized · 78a5255f
      Linus Torvalds authored
      We have some rather random rules about when we accept the
      "maybe-initialized" warnings, and when we don't.
      
      For example, we consider it unreliable for gcc versions < 4.9, but also
      if -O3 is enabled, or if optimizing for size.  And then various kernel
      config options disabled it, because they know that they trigger that
      warning by confusing gcc sufficiently (ie PROFILE_ALL_BRANCHES).
      
      And now gcc-10 seems to be introducing a lot of those warnings too, so
      it falls under the same heading as 4.9 did.
      
      At the same time, we have a very straightforward way to _enable_ that
      warning when wanted: use "W=2" to enable more warnings.
      
      So stop playing these ad-hoc games, and just disable that warning by
      default, with the known and straight-forward "if you want to work on the
      extra compiler warnings, use W=123".
      
      Would it be great to have code that is always so obvious that it never
      confuses the compiler whether a variable is used initialized or not?
      Yes, it would.  In a perfect world, the compilers would be smarter, and
      our source code would be simpler.
      
      That's currently not the world we live in, though.
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      78a5255f
    • Linus Torvalds's avatar
      Merge tag 'io_uring-5.7-2020-05-08' of git://git.kernel.dk/linux-block · 1d3962ae
      Linus Torvalds authored
      Pull io_uring fixes from Jens Axboe:
      
       - Fix finish_wait() balancing in file cancelation (Xiaoguang)
      
       - Ensure early cleanup of resources in ring map failure (Xiaoguang)
      
       - Ensure IORING_OP_SLICE does the right file mode checks (Pavel)
      
       - Remove file opening from openat/openat2/statx, it's not needed and
         messes with O_PATH
      
      * tag 'io_uring-5.7-2020-05-08' of git://git.kernel.dk/linux-block:
        io_uring: don't use 'fd' for openat/openat2/statx
        splice: move f_mode checks to do_{splice,tee}()
        io_uring: handle -EFAULT properly in io_uring_setup()
        io_uring: fix mismatched finish_wait() calls in io_uring_cancel_files()
      1d3962ae
  4. 08 May, 2020 20 commits
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · d5eeab8d
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "Four minor fixes, all in drivers (qla2xxx, ibmvfc, ibmvscsi)"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: ibmvscsi: Fix WARN_ON during event pool release
        scsi: ibmvfc: Don't send implicit logouts prior to NPIV login
        scsi: qla2xxx: Delete all sessions before unregister local nvme port
        scsi: qla2xxx: Fix hang when issuing nvme disconnect-all in NPIV
      d5eeab8d
    • Linus Torvalds's avatar
      Merge tag 'ceph-for-5.7-rc5' of git://github.com/ceph/ceph-client · eb24fdd8
      Linus Torvalds authored
      Pull ceph fixes from Ilya Dryomov:
       "Fixes for an endianness handling bug that prevented mounts on
        big-endian arches, a spammy log message and a couple error paths.
      
        Also included a MAINTAINERS update"
      
      * tag 'ceph-for-5.7-rc5' of git://github.com/ceph/ceph-client:
        ceph: demote quotarealm lookup warning to a debug message
        MAINTAINERS: remove myself as ceph co-maintainer
        ceph: fix double unlock in handle_cap_export()
        ceph: fix special error code in ceph_try_get_caps()
        ceph: fix endianness bug when handling MDS session feature bits
      eb24fdd8
    • Luis Henriques's avatar
      ceph: demote quotarealm lookup warning to a debug message · 12ae44a4
      Luis Henriques authored
      A misconfigured cephx can easily result in having the kernel client
      flooding the logs with:
      
        ceph: Can't lookup inode 1 (err: -13)
      
      Change this message to debug level.
      
      Cc: stable@vger.kernel.org
      URL: https://tracker.ceph.com/issues/44546Signed-off-by: default avatarLuis Henriques <lhenriques@suse.com>
      Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
      Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
      12ae44a4
    • Linus Torvalds's avatar
      Merge tag 'char-misc-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc · 4334f30e
      Linus Torvalds authored
      Pull char/misc driver fixes from Greg KH:
       "Here are some small driver fixes for 5.7-rc5 that resolve a number of
        minor reported issues:
      
         - mhi bus driver fixes found as people actually use the code
      
         - phy driver fixes and compat string additions
      
         - most driver fix due to link order changing when the core moved out
           of staging
      
         - mei driver fix
      
         - interconnect build warning fix
      
        All of these have been in linux-next for a while with no reported
        issues"
      
      * tag 'char-misc-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
        bus: mhi: core: Fix channel device name conflict
        bus: mhi: core: Fix typo in comment
        bus: mhi: core: Offload register accesses to the controller
        bus: mhi: core: Remove link_status() callback
        bus: mhi: core: Make sure to powerdown if mhi_sync_power_up fails
        bus: mhi: Fix parsing of mhi_flags
        mei: me: disable mei interface on LBG servers.
        phy: qualcomm: usb-hs-28nm: Prepare clocks in init
        MAINTAINERS: Add Vinod Koul as Generic PHY co-maintainer
        interconnect: qcom: Move the static keyword to the front of declaration
        most: core: use function subsys_initcall()
        bus: mhi: core: Fix a NULL vs IS_ERR check in mhi_create_devices()
        phy: qcom-qusb2: Re add "qcom,sdm845-qusb2-phy" compat string
        phy: tegra: Select USB_COMMON for usb_get_maximum_speed()
      4334f30e
    • Linus Torvalds's avatar
      Merge tag 'driver-core-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core · c61529f6
      Linus Torvalds authored
      Pull driver core fixes from Greg KH:
       "Here are a number of small driver core fixes for 5.7-rc5 to resolve a
        bunch of reported issues with the current tree.
      
        Biggest here are the reverts and patches from John Stultz to resolve a
        bunch of deferred probe regressions we have been seeing in 5.7-rc
        right now.
      
        Along with those are some other smaller fixes:
      
         - coredump crash fix
      
         - devlink fix for when permissive mode was enabled
      
         - amba and platform device dma_parms fixes
      
         - component error silenced for when deferred probe happens
      
        All of these have been in linux-next for a while with no reported
        issues"
      
      * tag 'driver-core-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
        regulator: Revert "Use driver_deferred_probe_timeout for regulator_init_complete_work"
        driver core: Ensure wait_for_device_probe() waits until the deferred_probe_timeout fires
        driver core: Use dev_warn() instead of dev_WARN() for deferred_probe_timeout warnings
        driver core: Revert default driver_deferred_probe_timeout value to 0
        component: Silence bind error on -EPROBE_DEFER
        driver core: Fix handling of fw_devlink=permissive
        coredump: fix crash when umh is disabled
        amba: Initialize dma_parms for amba devices
        driver core: platform: Initialize dma_parms for platform devices
      c61529f6
    • Linus Torvalds's avatar
      Merge tag 'staging-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging · e7a1c733
      Linus Torvalds authored
      Pull staging driver fixes from Greg KH:
       "Here are three small driver fixes for 5.7-rc5.
      
        Two of these are documentation fixes:
      
         - MAINTAINERS update due to removed driver
      
         - removing Wolfram from the ks7010 driver TODO file
      
        The other patch is a real fix:
      
         - fix gasket driver to proper check the return value of a call
      
        All of these have been in linux-next for a while with no reported
        issues"
      
      * tag 'staging-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
        staging: gasket: Check the return value of gasket_get_bar_index()
        staging: ks7010: remove me from CC list
        MAINTAINERS: remove entry after hp100 driver removal
      e7a1c733
    • Linus Torvalds's avatar
      Merge tag 'tty-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty · cbd0e482
      Linus Torvalds authored
      Pull tty/serial fixes from Greg KH:
       "Here are three small TTY/Serial/VT fixes for 5.7-rc5:
      
         - revert for the bcm63xx driver "fix" that was incorrect
      
         - vt unicode console bugfix
      
         - xilinx_uartps console driver fix
      
        All of these have been in linux next with no reported issues"
      
      * tag 'tty-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
        tty: xilinx_uartps: Fix missing id assignment to the console
        vt: fix unicode console freeing with a common interface
        Revert "tty: serial: bcm63xx: fix missing clk_put() in bcm63xx_uart"
      cbd0e482
    • Linus Torvalds's avatar
      Merge tag 'usb-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb · 0a0b96b2
      Linus Torvalds authored
      Pull USB fixes from Greg KH:
       "Here are some small USB fixes for 5.7-rc5 to resolve some reported
        issues:
      
         - syzbot found problems fixed
      
         - usbfs dma mapping fix
      
         - typec bugfixs
      
         - chipidea bugfix
      
         - usb4/thunderbolt fix
      
         - new device ids/quirks
      
        All of these have been in linux-next for a while with no reported
        issues"
      
      * tag 'usb-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
        usb: chipidea: msm: Ensure proper controller reset using role switch API
        usb: typec: mux: intel: Handle alt mode HPD_HIGH
        usb: usbfs: correct kernel->user page attribute mismatch
        usb: typec: intel_pmc_mux: Fix the property names
        USB: core: Fix misleading driver bug report
        USB: serial: qcserial: Add DW5816e support
        USB: uas: add quirk for LaCie 2Big Quadra
        thunderbolt: Check return value of tb_sw_read() in usb4_switch_op()
        USB: serial: garmin_gps: add sanity checking for data length
      0a0b96b2
    • Linus Torvalds's avatar
      Merge tag 'drm-fixes-2020-05-08' of git://anongit.freedesktop.org/drm/drm · 775a8e03
      Linus Torvalds authored
      Pull drm fixes from Dave Airlie:
       "Another pretty normal week. I didn't get any i915 fixes yet, so next
        week I'd expect double the usual i915, but otherwise a bunch of amdgpu
        and some scattered other fixes.
      
        hdcp:
         - fix HDCP regression
      
        amdgpu:
         - Runtime PM fixes
         - DC fix for PPC
         - Misc DC fixes
      
        virtio:
         - fix context ordering issue
      
        sun4i:
         - old gcc warning fix
      
        ingenic-drm:
         - missing module support"
      
      * tag 'drm-fixes-2020-05-08' of git://anongit.freedesktop.org/drm/drm:
        drm/amd/display: Prevent dpcd reads with passive dongles
        drm/amd/display: fix counter in wait_for_no_pipes_pending
        drm/amd/display: Update DCN2.1 DV Code Revision
        drm: Fix HDCP failures when SRM fw is missing
        sun6i: dsi: fix gcc-4.8
        drm: ingenic-drm: add MODULE_DEVICE_TABLE
        drm/virtio: create context before RESOURCE_CREATE_2D in 3D mode
        drm/amd/display: work around fp code being emitted outside of DC_FP_START/END
        drm/amdgpu/dc: Use WARN_ON_ONCE for ASSERT
        drm/amdgpu: drop redundant cg/pg ungate on runpm enter
        drm/amdgpu: move kfd suspend after ip_suspend_phase1
      775a8e03
    • Linus Torvalds's avatar
      Merge branch 'akpm' (patches from Andrew) · af38553c
      Linus Torvalds authored
      Merge misc fixes from Andrew Morton:
       "14 fixes and one selftest to verify the ipc fixes herein"
      
      * emailed patches from Andrew Morton <akpm@linux-foundation.org>:
        mm: limit boost_watermark on small zones
        ubsan: disable UBSAN_ALIGNMENT under COMPILE_TEST
        mm/vmscan: remove unnecessary argument description of isolate_lru_pages()
        epoll: atomically remove wait entry on wake up
        kselftests: introduce new epoll60 testcase for catching lost wakeups
        percpu: make pcpu_alloc() aware of current gfp context
        mm/slub: fix incorrect interpretation of s->offset
        scripts/gdb: repair rb_first() and rb_last()
        eventpoll: fix missing wakeup for ovflist in ep_poll_callback
        arch/x86/kvm/svm/sev.c: change flag passed to GUP fast in sev_pin_memory()
        scripts/decodecode: fix trapping instruction formatting
        kernel/kcov.c: fix typos in kcov_remote_start documentation
        mm/page_alloc: fix watchdog soft lockups during set_zone_contiguous()
        mm, memcg: fix error return value of mem_cgroup_css_alloc()
        ipc/mqueue.c: change __do_notify() to bypass check_kill_permission()
      af38553c
    • Julia Lawall's avatar
      iommu/virtio: Reverse arguments to list_add · fb3637a1
      Julia Lawall authored
      Elsewhere in the file, there is a list_for_each_entry with
      &vdev->resv_regions as the second argument, suggesting that
      &vdev->resv_regions is the list head.  So exchange the
      arguments on the list_add call to put the list head in the
      second argument.
      
      Fixes: 2a5a3148 ("iommu/virtio: Add probe request")
      Signed-off-by: default avatarJulia Lawall <Julia.Lawall@inria.fr>
      Reviewed-by: default avatarJean-Philippe Brucker <jean-philippe@linaro.org>
      Link: https://lore.kernel.org/r/1588704467-13431-1-git-send-email-Julia.Lawall@inria.frSigned-off-by: default avatarJoerg Roedel <jroedel@suse.de>
      fb3637a1
    • Dave Airlie's avatar
      Merge tag 'drm-misc-fixes-2020-05-07' of git://anongit.freedesktop.org/drm/drm-misc into drm-fixes · a9fe6f18
      Dave Airlie authored
      A few minor fixes for an ordering issue in virtio, an (old) gcc warning
      in sun4i, a probe issue in ingenic-drm and a regression in the HDCP
      support.
      Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      
      From: Maxime Ripard <maxime@cerno.tech>
      Link: https://patchwork.freedesktop.org/patch/msgid/20200507160130.id64niqgf5wsha4u@gilmour.lan
      a9fe6f18
    • Dave Airlie's avatar
      Merge tag 'amd-drm-fixes-5.7-2020-05-06' of... · c61b0b97
      Dave Airlie authored
      Merge tag 'amd-drm-fixes-5.7-2020-05-06' of git://people.freedesktop.org/~agd5f/linux into drm-fixes
      
      amd-drm-fixes-5.7-2020-05-06:
      
      amdgpu:
      - Runtime PM fixes
      - DC fix for PPC
      - Misc DC fixes
      Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
      From: Alex Deucher <alexdeucher@gmail.com>
      Link: https://patchwork.freedesktop.org/patch/msgid/20200506212257.3893-1-alexander.deucher@amd.com
      c61b0b97
    • Linus Torvalds's avatar
      Merge branch 'for-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security · 79dede78
      Linus Torvalds authored
      Pull security subsystem fix from James Morris:
       "Fix the default value of fs_context_parse_param hook"
      
      * 'for-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
        security: Fix the default value of fs_context_parse_param hook
      79dede78
    • Henry Willard's avatar
      mm: limit boost_watermark on small zones · 14f69140
      Henry Willard authored
      Commit 1c30844d ("mm: reclaim small amounts of memory when an
      external fragmentation event occurs") adds a boost_watermark() function
      which increases the min watermark in a zone by at least
      pageblock_nr_pages or the number of pages in a page block.
      
      On Arm64, with 64K pages and 512M huge pages, this is 8192 pages or
      512M.  It does this regardless of the number of managed pages managed in
      the zone or the likelihood of success.
      
      This can put the zone immediately under water in terms of allocating
      pages from the zone, and can cause a small machine to fail immediately
      due to OoM.  Unlike set_recommended_min_free_kbytes(), which
      substantially increases min_free_kbytes and is tied to THP,
      boost_watermark() can be called even if THP is not active.
      
      The problem is most likely to appear on architectures such as Arm64
      where pageblock_nr_pages is very large.
      
      It is desirable to run the kdump capture kernel in as small a space as
      possible to avoid wasting memory.  In some architectures, such as Arm64,
      there are restrictions on where the capture kernel can run, and
      therefore, the space available.  A capture kernel running in 768M can
      fail due to OoM immediately after boost_watermark() sets the min in zone
      DMA32, where most of the memory is, to 512M.  It fails even though there
      is over 500M of free memory.  With boost_watermark() suppressed, the
      capture kernel can run successfully in 448M.
      
      This patch limits boost_watermark() to boosting a zone's min watermark
      only when there are enough pages that the boost will produce positive
      results.  In this case that is estimated to be four times as many pages
      as pageblock_nr_pages.
      
      Mel said:
      
      : There is no harm in marking it stable.  Clearly it does not happen very
      : often but it's not impossible.  32-bit x86 is a lot less common now
      : which would previously have been vulnerable to triggering this easily.
      : ppc64 has a larger base page size but typically only has one zone.
      : arm64 is likely the most vulnerable, particularly when CMA is
      : configured with a small movable zone.
      
      Fixes: 1c30844d ("mm: reclaim small amounts of memory when an external fragmentation event occurs")
      Signed-off-by: default avatarHenry Willard <henry.willard@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Reviewed-by: default avatarDavid Hildenbrand <david@redhat.com>
      Acked-by: default avatarMel Gorman <mgorman@techsingularity.net>
      Cc: Vlastimil Babka <vbabka@suse.cz>
      Cc: <stable@vger.kernel.org>
      Link: http://lkml.kernel.org/r/1588294148-6586-1-git-send-email-henry.willard@oracle.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      14f69140
    • Kees Cook's avatar
      ubsan: disable UBSAN_ALIGNMENT under COMPILE_TEST · 8d58f222
      Kees Cook authored
      The documentation for UBSAN_ALIGNMENT already mentions that it should
      not be used on all*config builds (and for efficient-unaligned-access
      architectures), so just refactor the Kconfig to correctly implement this
      so randconfigs will stop creating insane images that freak out objtool
      under CONFIG_UBSAN_TRAP (due to the false positives producing functions
      that never return, etc).
      
      Link: http://lkml.kernel.org/r/202005011433.C42EA3E2D@keescook
      Fixes: 0887a7eb ("ubsan: add trap instrumentation option")
      Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      Reported-by: default avatarRandy Dunlap <rdunlap@infradead.org>
        Link: https://lore.kernel.org/linux-next/202004231224.D6B3B650@keescook/Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8d58f222
    • Qiwu Chen's avatar
      mm/vmscan: remove unnecessary argument description of isolate_lru_pages() · 17e34526
      Qiwu Chen authored
      Since commit a9e7c39f ("mm/vmscan.c: remove 7th argument of
      isolate_lru_pages()"), the explanation of 'mode' argument has been
      unnecessary.  Let's remove it.
      Signed-off-by: default avatarQiwu Chen <chenqiwu@xiaomi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Link: http://lkml.kernel.org/r/20200501090346.2894-1-chenqiwu@xiaomi.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      17e34526
    • Roman Penyaev's avatar
      epoll: atomically remove wait entry on wake up · 412895f0
      Roman Penyaev authored
      This patch does two things:
      
       - fixes a lost wakeup introduced by commit 339ddb53 ("fs/epoll:
         remove unnecessary wakeups of nested epoll")
      
       - improves performance for events delivery.
      
      The description of the problem is the following: if N (>1) threads are
      waiting on ep->wq for new events and M (>1) events come, it is quite
      likely that >1 wakeups hit the same wait queue entry, because there is
      quite a big window between __add_wait_queue_exclusive() and the
      following __remove_wait_queue() calls in ep_poll() function.
      
      This can lead to lost wakeups, because thread, which was woken up, can
      handle not all the events in ->rdllist.  (in better words the problem is
      described here: https://lkml.org/lkml/2019/10/7/905)
      
      The idea of the current patch is to use init_wait() instead of
      init_waitqueue_entry().
      
      Internally init_wait() sets autoremove_wake_function as a callback,
      which removes the wait entry atomically (under the wq locks) from the
      list, thus the next coming wakeup hits the next wait entry in the wait
      queue, thus preventing lost wakeups.
      
      Problem is very well reproduced by the epoll60 test case [1].
      
      Wait entry removal on wakeup has also performance benefits, because
      there is no need to take a ep->lock and remove wait entry from the queue
      after the successful wakeup.  Here is the timing output of the epoll60
      test case:
      
        With explicit wakeup from ep_scan_ready_list() (the state of the
        code prior 339ddb53):
      
          real    0m6.970s
          user    0m49.786s
          sys     0m0.113s
      
       After this patch:
      
         real    0m5.220s
         user    0m36.879s
         sys     0m0.019s
      
      The other testcase is the stress-epoll [2], where one thread consumes
      all the events and other threads produce many events:
      
        With explicit wakeup from ep_scan_ready_list() (the state of the
        code prior 339ddb53):
      
          threads  events/ms  run-time ms
                8       5427         1474
               16       6163         2596
               32       6824         4689
               64       7060         9064
              128       6991        18309
      
       After this patch:
      
          threads  events/ms  run-time ms
                8       5598         1429
               16       7073         2262
               32       7502         4265
               64       7640         8376
              128       7634        16767
      
       (number of "events/ms" represents event bandwidth, thus higher is
        better; number of "run-time ms" represents overall time spent
        doing the benchmark, thus lower is better)
      
      [1] tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c
      [2] https://github.com/rouming/test-tools/blob/master/stress-epoll.cSigned-off-by: default avatarRoman Penyaev <rpenyaev@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Reviewed-by: default avatarJason Baron <jbaron@akamai.com>
      Cc: Khazhismel Kumykov <khazhy@google.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Heiher <r@hev.cc>
      Cc: <stable@vger.kernel.org>
      Link: http://lkml.kernel.org/r/20200430130326.1368509-2-rpenyaev@suse.deSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      412895f0
    • Roman Penyaev's avatar
      kselftests: introduce new epoll60 testcase for catching lost wakeups · 474328c0
      Roman Penyaev authored
      This test case catches lost wake up introduced by commit 339ddb53
      ("fs/epoll: remove unnecessary wakeups of nested epoll")
      
      The test is simple: we have 10 threads and 10 event fds.  Each thread
      can harvest only 1 event.  1 producer fires all 10 events at once and
      waits that all 10 events will be observed by 10 threads.
      
      In case of lost wakeup epoll_wait() will timeout and 0 will be returned.
      
      Test case catches two sort of problems: forgotten wakeup on event, which
      hits the ->ovflist list, this problem was fixed by:
      
        5a2513239750 ("eventpoll: fix missing wakeup for ovflist in ep_poll_callback")
      
      the other problem is when several sequential events hit the same waiting
      thread, thus other waiters get no wakeups.  Problem is fixed in the
      following patch.
      Signed-off-by: default avatarRoman Penyaev <rpenyaev@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: Khazhismel Kumykov <khazhy@google.com>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Heiher <r@hev.cc>
      Cc: Jason Baron <jbaron@akamai.com>
      Link: http://lkml.kernel.org/r/20200430130326.1368509-1-rpenyaev@suse.deSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      474328c0
    • Filipe Manana's avatar
      percpu: make pcpu_alloc() aware of current gfp context · 28307d93
      Filipe Manana authored
      Since 5.7-rc1, on btrfs we have a percpu counter initialization for
      which we always pass a GFP_KERNEL gfp_t argument (this happens since
      commit 2992df73 ("btrfs: Implement DREW lock")).
      
      That is safe in some contextes but not on others where allowing fs
      reclaim could lead to a deadlock because we are either holding some
      btrfs lock needed for a transaction commit or holding a btrfs
      transaction handle open.  Because of that we surround the call to the
      function that initializes the percpu counter with a NOFS context using
      memalloc_nofs_save() (this is done at btrfs_init_fs_root()).
      
      However it turns out that this is not enough to prevent a possible
      deadlock because percpu_alloc() determines if it is in an atomic context
      by looking exclusively at the gfp flags passed to it (GFP_KERNEL in this
      case) and it is not aware that a NOFS context is set.
      
      Because percpu_alloc() thinks it is in a non atomic context it locks the
      pcpu_alloc_mutex.  This can result in a btrfs deadlock when
      pcpu_balance_workfn() is running, has acquired that mutex and is waiting
      for reclaim, while the btrfs task that called percpu_counter_init() (and
      therefore percpu_alloc()) is holding either the btrfs commit_root
      semaphore or a transaction handle (done fs/btrfs/backref.c:
      iterate_extent_inodes()), which prevents reclaim from finishing as an
      attempt to commit the current btrfs transaction will deadlock.
      
      Lockdep reports this issue with the following trace:
      
        ======================================================
        WARNING: possible circular locking dependency detected
        5.6.0-rc7-btrfs-next-77 #1 Not tainted
        ------------------------------------------------------
        kswapd0/91 is trying to acquire lock:
        ffff8938a3b3fdc8 (&delayed_node->mutex){+.+.}, at: __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs]
      
        but task is already holding lock:
        ffffffffb4f0dbc0 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30
      
        which lock already depends on the new lock.
      
        the existing dependency chain (in reverse order) is:
      
        -> #4 (fs_reclaim){+.+.}:
               fs_reclaim_acquire.part.0+0x25/0x30
               __kmalloc+0x5f/0x3a0
               pcpu_create_chunk+0x19/0x230
               pcpu_balance_workfn+0x56a/0x680
               process_one_work+0x235/0x5f0
               worker_thread+0x50/0x3b0
               kthread+0x120/0x140
               ret_from_fork+0x3a/0x50
      
        -> #3 (pcpu_alloc_mutex){+.+.}:
               __mutex_lock+0xa9/0xaf0
               pcpu_alloc+0x480/0x7c0
               __percpu_counter_init+0x50/0xd0
               btrfs_drew_lock_init+0x22/0x70 [btrfs]
               btrfs_get_fs_root+0x29c/0x5c0 [btrfs]
               resolve_indirect_refs+0x120/0xa30 [btrfs]
               find_parent_nodes+0x50b/0xf30 [btrfs]
               btrfs_find_all_leafs+0x60/0xb0 [btrfs]
               iterate_extent_inodes+0x139/0x2f0 [btrfs]
               iterate_inodes_from_logical+0xa1/0xe0 [btrfs]
               btrfs_ioctl_logical_to_ino+0xb4/0x190 [btrfs]
               btrfs_ioctl+0x165a/0x3130 [btrfs]
               ksys_ioctl+0x87/0xc0
               __x64_sys_ioctl+0x16/0x20
               do_syscall_64+0x5c/0x260
               entry_SYSCALL_64_after_hwframe+0x49/0xbe
      
        -> #2 (&fs_info->commit_root_sem){++++}:
               down_write+0x38/0x70
               btrfs_cache_block_group+0x2ec/0x500 [btrfs]
               find_free_extent+0xc6a/0x1600 [btrfs]
               btrfs_reserve_extent+0x9b/0x180 [btrfs]
               btrfs_alloc_tree_block+0xc1/0x350 [btrfs]
               alloc_tree_block_no_bg_flush+0x4a/0x60 [btrfs]
               __btrfs_cow_block+0x122/0x5a0 [btrfs]
               btrfs_cow_block+0x106/0x240 [btrfs]
               commit_cowonly_roots+0x55/0x310 [btrfs]
               btrfs_commit_transaction+0x509/0xb20 [btrfs]
               sync_filesystem+0x74/0x90
               generic_shutdown_super+0x22/0x100
               kill_anon_super+0x14/0x30
               btrfs_kill_super+0x12/0x20 [btrfs]
               deactivate_locked_super+0x31/0x70
               cleanup_mnt+0x100/0x160
               task_work_run+0x93/0xc0
               exit_to_usermode_loop+0xf9/0x100
               do_syscall_64+0x20d/0x260
               entry_SYSCALL_64_after_hwframe+0x49/0xbe
      
        -> #1 (&space_info->groups_sem){++++}:
               down_read+0x3c/0x140
               find_free_extent+0xef6/0x1600 [btrfs]
               btrfs_reserve_extent+0x9b/0x180 [btrfs]
               btrfs_alloc_tree_block+0xc1/0x350 [btrfs]
               alloc_tree_block_no_bg_flush+0x4a/0x60 [btrfs]
               __btrfs_cow_block+0x122/0x5a0 [btrfs]
               btrfs_cow_block+0x106/0x240 [btrfs]
               btrfs_search_slot+0x50c/0xd60 [btrfs]
               btrfs_lookup_inode+0x3a/0xc0 [btrfs]
               __btrfs_update_delayed_inode+0x90/0x280 [btrfs]
               __btrfs_commit_inode_delayed_items+0x81f/0x870 [btrfs]
               __btrfs_run_delayed_items+0x8e/0x180 [btrfs]
               btrfs_commit_transaction+0x31b/0xb20 [btrfs]
               iterate_supers+0x87/0xf0
               ksys_sync+0x60/0xb0
               __ia32_sys_sync+0xa/0x10
               do_syscall_64+0x5c/0x260
               entry_SYSCALL_64_after_hwframe+0x49/0xbe
      
        -> #0 (&delayed_node->mutex){+.+.}:
               __lock_acquire+0xef0/0x1c80
               lock_acquire+0xa2/0x1d0
               __mutex_lock+0xa9/0xaf0
               __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs]
               btrfs_evict_inode+0x40d/0x560 [btrfs]
               evict+0xd9/0x1c0
               dispose_list+0x48/0x70
               prune_icache_sb+0x54/0x80
               super_cache_scan+0x124/0x1a0
               do_shrink_slab+0x176/0x440
               shrink_slab+0x23a/0x2c0
               shrink_node+0x188/0x6e0
               balance_pgdat+0x31d/0x7f0
               kswapd+0x238/0x550
               kthread+0x120/0x140
               ret_from_fork+0x3a/0x50
      
        other info that might help us debug this:
      
        Chain exists of:
          &delayed_node->mutex --> pcpu_alloc_mutex --> fs_reclaim
      
         Possible unsafe locking scenario:
      
               CPU0                    CPU1
               ----                    ----
          lock(fs_reclaim);
                                       lock(pcpu_alloc_mutex);
                                       lock(fs_reclaim);
          lock(&delayed_node->mutex);
      
         *** DEADLOCK ***
      
        3 locks held by kswapd0/91:
         #0: (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30
         #1: (shrinker_rwsem){++++}, at: shrink_slab+0x12f/0x2c0
         #2: (&type->s_umount_key#43){++++}, at: trylock_super+0x16/0x50
      
        stack backtrace:
        CPU: 1 PID: 91 Comm: kswapd0 Not tainted 5.6.0-rc7-btrfs-next-77 #1
        Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014
        Call Trace:
         dump_stack+0x8f/0xd0
         check_noncircular+0x170/0x190
         __lock_acquire+0xef0/0x1c80
         lock_acquire+0xa2/0x1d0
         __mutex_lock+0xa9/0xaf0
         __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs]
         btrfs_evict_inode+0x40d/0x560 [btrfs]
         evict+0xd9/0x1c0
         dispose_list+0x48/0x70
         prune_icache_sb+0x54/0x80
         super_cache_scan+0x124/0x1a0
         do_shrink_slab+0x176/0x440
         shrink_slab+0x23a/0x2c0
         shrink_node+0x188/0x6e0
         balance_pgdat+0x31d/0x7f0
         kswapd+0x238/0x550
         kthread+0x120/0x140
         ret_from_fork+0x3a/0x50
      
      This could be fixed by making btrfs pass GFP_NOFS instead of GFP_KERNEL
      to percpu_counter_init() in contextes where it is not reclaim safe,
      however that type of approach is discouraged since
      memalloc_[nofs|noio]_save() were introduced.  Therefore this change
      makes pcpu_alloc() look up into an existing nofs/noio context before
      deciding whether it is in an atomic context or not.
      Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Acked-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarDennis Zhou <dennis@kernel.org>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Christoph Lameter <cl@linux.com>
      Link: http://lkml.kernel.org/r/20200430164356.15543-1-fdmanana@kernel.orgSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      28307d93