- 05 May, 2017 25 commits
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Benjamin Herrenschmidt authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 7ed23e1b upstream. On Power8 & Power9 the early CPU inititialisation in __init_HFSCR() turns on HFSCR[TM] (Hypervisor Facility Status and Control Register [Transactional Memory]), but that doesn't take into account that TM might be disabled by CPU features, or disabled by the kernel being built with CONFIG_PPC_TRANSACTIONAL_MEM=n. So later in boot, when we have setup the CPU features, clear HSCR[TM] if the TM CPU feature has been disabled. We use CPU_FTR_TM_COMP to account for the CONFIG_PPC_TRANSACTIONAL_MEM=n case. Without this a KVM guest might try use TM, even if told not to, and cause an oops in the host kernel. Typically the oops is seen in __kvmppc_vcore_entry() and may or may not be fatal to the host, but is always bad news. In practice all shipping CPU revisions do support TM, and all host kernels we are aware of build with TM support enabled, so no one should actually be able to hit this in the wild. Fixes: 2a3563b0 ("powerpc: Setup in HFSCR for POWER8") Cc: stable@vger.kernel.org # v3.10+ Signed-off-by:
Benjamin Herrenschmidt <benh@kernel.crashing.org> Tested-by:
Sam Bobroff <sam.bobroff@au1.ibm.com> [mpe: Rewrite change log with input from Sam, add Fixes/stable] Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> [sb: Backported to linux-4.4.y: adjusted context] Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
Stefan Bader <stefan.bader@canonical.com> Signed-off-by:
Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
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Minchan Kim authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit d72e9a7a upstream. The copy_page is optimized memcpy for page-alinged address. If it is used with non-page aligned address, it can corrupt memory which means system corruption. With zram, it can happen with 1. 64K architecture 2. partial IO 3. slub debug Partial IO need to allocate a page and zram allocates it via kmalloc. With slub debug, kmalloc(PAGE_SIZE) doesn't return page-size aligned address. And finally, copy_page(mem, cmem) corrupts memory. So, this patch changes it to memcpy. Actuaully, we don't need to change zram_bvec_write part because zsmalloc returns page-aligned address in case of PAGE_SIZE class but it's not good to rely on the internal of zsmalloc. Note: When this patch is merged to stable, clear_page should be fixed, too. Unfortunately, recent zram removes it by "same page merge" feature so it's hard to backport this patch to -stable tree. I will handle it when I receive the mail from stable tree maintainer to merge this patch to backport. Fixes: 42e99bd9 ("zram: optimize memory operations with clear_page()/copy_page()") Link: http://lkml.kernel.org/r/1492042622-12074-2-git-send-email-minchan@kernel.orgSigned-off-by:
Minchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
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Paolo Bonzini authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 06ce521a upstream. handle_vmon gets a reference on VMXON region page, but does not release it. Release the reference. Found by syzkaller; based on a patch by Dmitry. Reported-by:
Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com> [bwh: Backported to 3.16: use skip_emulated_instruction()] Signed-off-by:
Ben Hutchings <ben@decadent.org.uk> Signed-off-by:
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Greg Kroah-Hartman authored
BugLink: http://bugs.launchpad.net/bugs/1687629 This reverts commit 6280ac93 which is commit 6c356eda upstream. It shouldn't have been included in a stable release. Reported-by:
Amit Pundir <amit.pundir@linaro.org> Cc: Felix Fietkau <nbd@nbd.name> Cc: John Crispin <john@phrozen.org> Cc: James Hogan <james.hogan@imgtec.com> Signed-off-by:
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Max Bires authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit f2cfa58b upstream. Without a bool string present, using "# CONFIG_DEVPORT is not set" in defconfig files would not actually unset devport. This esnured that /dev/port was always on, but there are reasons a user may wish to disable it (smaller kernel, attack surface reduction) if it's not being used. Adding a message here in order to make this user visible. Signed-off-by:
Max Bires <jbires@google.com> Acked-by:
Arnd Bergmann <arnd@arndb.de> Signed-off-by:
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Geert Uytterhoeven authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 309124e2 upstream. According to full-history-linux commit d3794f4fa7c3edc3 ("[PATCH] M68k update (part 25)"), port operations are allowed on m68k if CONFIG_ISA is defined. However, commit 153dcc54 ("[PATCH] mem driver: fix conditional on isa i/o support") accidentally changed an "||" into an "&&", disabling it completely on m68k. This logic was retained when introducing the DEVPORT symbol in commit 4f911d64 ("Make /dev/port conditional on config symbol"). Drop the bogus dependency on !M68K to fix this. Fixes: 153dcc54 ("[PATCH] mem driver: fix conditional on isa i/o support") Signed-off-by:
Geert Uytterhoeven <geert@linux-m68k.org> Tested-by:
Al Stone <ahs3@redhat.com> Signed-off-by:
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Steven Rostedt (VMware) authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 82cc4fc2 upstream. When two function probes are added to set_ftrace_filter, and then one of them is removed, the update to the function locations is not performed, and the record keeping of the function states are corrupted, and causes an ftrace_bug() to occur. This is easily reproducable by adding two probes, removing one, and then adding it back again. # cd /sys/kernel/debug/tracing # echo schedule:traceoff > set_ftrace_filter # echo do_IRQ:traceoff > set_ftrace_filter # echo \!do_IRQ:traceoff > /debug/tracing/set_ftrace_filter # echo do_IRQ:traceoff > set_ftrace_filter Causes: ------------[ cut here ]------------ WARNING: CPU: 2 PID: 1098 at kernel/trace/ftrace.c:2369 ftrace_get_addr_curr+0x143/0x220 Modules linked in: [...] CPU: 2 PID: 1098 Comm: bash Not tainted 4.10.0-test+ #405 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012 Call Trace: dump_stack+0x68/0x9f __warn+0x111/0x130 ? trace_irq_work_interrupt+0xa0/0xa0 warn_slowpath_null+0x1d/0x20 ftrace_get_addr_curr+0x143/0x220 ? __fentry__+0x10/0x10 ftrace_replace_code+0xe3/0x4f0 ? ftrace_int3_handler+0x90/0x90 ? printk+0x99/0xb5 ? 0xffffffff81000000 ftrace_modify_all_code+0x97/0x110 arch_ftrace_update_code+0x10/0x20 ftrace_run_update_code+0x1c/0x60 ftrace_run_modify_code.isra.48.constprop.62+0x8e/0xd0 register_ftrace_function_probe+0x4b6/0x590 ? ftrace_startup+0x310/0x310 ? debug_lockdep_rcu_enabled.part.4+0x1a/0x30 ? update_stack_state+0x88/0x110 ? ftrace_regex_write.isra.43.part.44+0x1d3/0x320 ? preempt_count_sub+0x18/0xd0 ? mutex_lock_nested+0x104/0x800 ? ftrace_regex_write.isra.43.part.44+0x1d3/0x320 ? __unwind_start+0x1c0/0x1c0 ? _mutex_lock_nest_lock+0x800/0x800 ftrace_trace_probe_callback.isra.3+0xc0/0x130 ? func_set_flag+0xe0/0xe0 ? __lock_acquire+0x642/0x1790 ? __might_fault+0x1e/0x20 ? trace_get_user+0x398/0x470 ? strcmp+0x35/0x60 ftrace_trace_onoff_callback+0x48/0x70 ftrace_regex_write.isra.43.part.44+0x251/0x320 ? match_records+0x420/0x420 ftrace_filter_write+0x2b/0x30 __vfs_write+0xd7/0x330 ? do_loop_readv_writev+0x120/0x120 ? locks_remove_posix+0x90/0x2f0 ? do_lock_file_wait+0x160/0x160 ? __lock_is_held+0x93/0x100 ? rcu_read_lock_sched_held+0x5c/0xb0 ? preempt_count_sub+0x18/0xd0 ? __sb_start_write+0x10a/0x230 ? vfs_write+0x222/0x240 vfs_write+0xef/0x240 SyS_write+0xab/0x130 ? SyS_read+0x130/0x130 ? trace_hardirqs_on_caller+0x182/0x280 ? trace_hardirqs_on_thunk+0x1a/0x1c entry_SYSCALL_64_fastpath+0x18/0xad RIP: 0033:0x7fe61c157c30 RSP: 002b:00007ffe87890258 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: ffffffff8114a410 RCX: 00007fe61c157c30 RDX: 0000000000000010 RSI: 000055814798f5e0 RDI: 0000000000000001 RBP: ffff8800c9027f98 R08: 00007fe61c422740 R09: 00007fe61ca53700 R10: 0000000000000073 R11: 0000000000000246 R12: 0000558147a36400 R13: 00007ffe8788f160 R14: 0000000000000024 R15: 00007ffe8788f15c ? trace_hardirqs_off_caller+0xc0/0x110 ---[ end trace 99fa09b3d9869c2c ]--- Bad trampoline accounting at: ffffffff81cc3b00 (do_IRQ+0x0/0x150) Fixes: 59df055f ("ftrace: trace different functions with a different tracer") Signed-off-by:
Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by:
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Tyler Baker authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 75eb5e1e upstream. The raw_spinlock in the IMX GPCV2 interupt chip is not initialized before usage. That results in a lockdep splat: INFO: trying to register non-static key. the code is fine but needs lockdep annotation. turning off the locking correctness validator. Add the missing raw_spin_lock_init() to the setup code. Fixes: e324c4dc ("irqchip/imx-gpcv2: IMX GPCv2 driver for wakeup sources") Signed-off-by:
Tyler Baker <tyler.baker@linaro.org> Reviewed-by:
Fabio Estevam <fabio.estevam@nxp.com> Cc: jason@lakedaemon.net Cc: marc.zyngier@arm.com Cc: shawnguo@kernel.org Cc: andrew.smirnov@gmail.com Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20170413222731.5917-1-tyler.baker@linaro.orgSigned-off-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Dan Williams authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 0beb2012 upstream. Holding the reconfig_mutex over a potential userspace fault sets up a lockdep dependency chain between filesystem-DAX and the libnvdimm ioctl path. Move the user access outside of the lock. [ INFO: possible circular locking dependency detected ] 4.11.0-rc3+ #13 Tainted: G W O ------------------------------------------------------- fallocate/16656 is trying to acquire lock: (&nvdimm_bus->reconfig_mutex){+.+.+.}, at: [<ffffffffa00080b1>] nvdimm_bus_lock+0x21/0x30 [libnvdimm] but task is already holding lock: (jbd2_handle){++++..}, at: [<ffffffff813b4944>] start_this_handle+0x104/0x460 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (jbd2_handle){++++..}: lock_acquire+0xbd/0x200 start_this_handle+0x16a/0x460 jbd2__journal_start+0xe9/0x2d0 __ext4_journal_start_sb+0x89/0x1c0 ext4_dirty_inode+0x32/0x70 __mark_inode_dirty+0x235/0x670 generic_update_time+0x87/0xd0 touch_atime+0xa9/0xd0 ext4_file_mmap+0x90/0xb0 mmap_region+0x370/0x5b0 do_mmap+0x415/0x4f0 vm_mmap_pgoff+0xd7/0x120 SyS_mmap_pgoff+0x1c5/0x290 SyS_mmap+0x22/0x30 entry_SYSCALL_64_fastpath+0x1f/0xc2 -> #1 (&mm->mmap_sem){++++++}: lock_acquire+0xbd/0x200 __might_fault+0x70/0xa0 __nd_ioctl+0x683/0x720 [libnvdimm] nvdimm_ioctl+0x8b/0xe0 [libnvdimm] do_vfs_ioctl+0xa8/0x740 SyS_ioctl+0x79/0x90 do_syscall_64+0x6c/0x200 return_from_SYSCALL_64+0x0/0x7a -> #0 (&nvdimm_bus->reconfig_mutex){+.+.+.}: __lock_acquire+0x16b6/0x1730 lock_acquire+0xbd/0x200 __mutex_lock+0x88/0x9b0 mutex_lock_nested+0x1b/0x20 nvdimm_bus_lock+0x21/0x30 [libnvdimm] nvdimm_forget_poison+0x25/0x50 [libnvdimm] nvdimm_clear_poison+0x106/0x140 [libnvdimm] pmem_do_bvec+0x1c2/0x2b0 [nd_pmem] pmem_make_request+0xf9/0x270 [nd_pmem] generic_make_request+0x118/0x3b0 submit_bio+0x75/0x150 Fixes: 62232e45 ("libnvdimm: control (ioctl) messages for nvdimm_bus and nvdimm devices") Cc: Dave Jiang <dave.jiang@intel.com> Reported-by:
Vishal Verma <vishal.l.verma@intel.com> Signed-off-by:
Dan Williams <dan.j.williams@intel.com> Signed-off-by:
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Juergen Gross authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 9121b15b upstream. Connecting to the backend isn't working reliably in xen-fbfront: in case XenbusStateInitWait of the backend has been missed the backend transition to XenbusStateConnected will trigger the connected state only without doing the actions required when the backend has connected. Signed-off-by:
Juergen Gross <jgross@suse.com> Reviewed-by:
Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by:
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by:
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Martin K. Petersen authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 7c856152 upstream. We previously made sure that the reported disk capacity was less than 0xffffffff blocks when the kernel was not compiled with large sector_t support (CONFIG_LBDAF). However, this check assumed that the capacity was reported in units of 512 bytes. Add a sanity check function to ensure that we only enable disks if the entire reported capacity can be expressed in terms of sector_t. Reported-by:
Steve Magnani <steve.magnani@digidescorp.com> Cc: Bart Van Assche <Bart.VanAssche@sandisk.com> Reviewed-by:
Bart Van Assche <Bart.VanAssche@sandisk.com> Signed-off-by:
Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by:
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Fam Zheng authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 67804145 upstream. If device reports a small max_xfer_blocks and a zero opt_xfer_blocks, we end up using BLK_DEF_MAX_SECTORS, which is wrong and r/w of that size may get error. [mkp: tweaked to avoid setting rw_max twice and added typecast] Fixes: ca369d51 ("block/sd: Fix device-imposed transfer length limits") Signed-off-by:
Fam Zheng <famz@redhat.com> Signed-off-by:
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Martin K. Petersen authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit a00a7862 upstream. Kefeng Wang discovered that old versions of the QEMU CD driver would return mangled mode data causing us to walk off the end of the buffer in an attempt to parse it. Sanity check the returned mode sense data. Reported-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Tested-by:
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Nicholas Bellinger authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 1c99de98 upstream. Once upon a time back in 2009, a work-around was added to support the GlobalSAN iSCSI initiator v3.3 for MacOSX, which during login did not propose nor respond to MaxBurstLength, FirstBurstLength, DefaultTime2Wait and DefaultTime2Retain keys. The work-around in iscsi_check_proposer_for_optional_reply() allowed the missing keys to be proposed, but did not require waiting for a response before moving to full feature phase operation. This allowed GlobalSAN v3.3 to work out-of-the box, and for many years we didn't run into login interopt issues with any other initiators.. Until recently, when Martin tried a QLogic 57840S iSCSI Offload HBA on Windows 2016 which completed login, but subsequently failed with: Got unknown iSCSI OpCode: 0x43 The issue was QLogic MSFT side did not propose DefaultTime2Wait + DefaultTime2Retain, so LIO proposes them itself, and immediately transitions to full feature phase because of the GlobalSAN hack. However, the QLogic MSFT side still attempts to respond to DefaultTime2Retain + DefaultTime2Wait, even though LIO has set ISCSI_FLAG_LOGIN_NEXT_STAGE3 + ISCSI_FLAG_LOGIN_TRANSIT in last login response. So while the QLogic MSFT side should have been proposing these two keys to start, it was doing the correct thing per RFC-3720 attempting to respond to proposed keys before transitioning to full feature phase. All that said, recent versions of GlobalSAN iSCSI (v5.3.0.541) does correctly propose the four keys during login, making the original work-around moot. So in order to allow QLogic MSFT to run unmodified as-is, go ahead and drop this long standing work-around. Reported-by:
Martin Svec <martin.svec@zoner.cz> Cc: Martin Svec <martin.svec@zoner.cz> Cc: Himanshu Madhani <Himanshu.Madhani@cavium.com> Cc: Arun Easi <arun.easi@cavium.com> Signed-off-by:
Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by:
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Nicholas Bellinger authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit efb2ea77 upstream. This patch fixes a iscsi-target specific TMR reference leak during session shutdown, that could occur when a TMR was quiesced before the hand-off back to iscsi-target code via transport_cmd_check_stop_to_fabric(). The reference leak happens because iscsit_free_cmd() was incorrectly skipping the final target_put_sess_cmd() for TMRs when transport_generic_free_cmd() returned zero because the se_cmd->cmd_kref did not reach zero, due to the missing se_cmd assignment in original code. The result was iscsi_cmd and it's associated se_cmd memory would be freed once se_sess->sess_cmd_map where released, but the associated se_tmr_req was leaked and remained part of se_device->dev_tmr_list. This bug would manfiest itself as kernel paging request OOPsen in core_tmr_lun_reset(), when a left-over se_tmr_req attempted to dereference it's se_cmd pointer that had already been released during normal session shutdown. To address this bug, go ahead and treat ISCSI_OP_SCSI_CMD and ISCSI_OP_SCSI_TMFUNC the same when there is an extra se_cmd->cmd_kref to drop in iscsit_free_cmd(), and use op_scsi to signal __iscsit_free_cmd() when the former needs to clear any further iscsi related I/O state. Reported-by:
Rob Millner <rlm@daterainc.com> Cc: Rob Millner <rlm@daterainc.com> Reported-by:
Chu Yuan Lin <cyl@datera.io> Cc: Chu Yuan Lin <cyl@datera.io> Tested-by:
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Dan Williams authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit b03b99a3 upstream. While reviewing the -stable patch for commit 86ef58a4 "nfit, libnvdimm: fix interleave set cookie calculation" Ben noted: "This is returning an int, thus it's effectively doing a 32-bit comparison and not the 64-bit comparison you say is needed." Update the compare operation to be immune to this integer demotion problem. Cc: Nicholas Moulin <nicholas.w.moulin@linux.intel.com> Fixes: 86ef58a4 ("nfit, libnvdimm: fix interleave set cookie calculation") Reported-by:
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Thomas Gleixner authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 6fdc6dd9 upstream. The vsyscall32 sysctl can racy against a concurrent fork when it switches from disabled to enabled: arch_setup_additional_pages() if (vdso32_enabled) --> No mapping sysctl.vsysscall32() --> vdso32_enabled = true create_elf_tables() ARCH_DLINFO_IA32 if (vdso32_enabled) { --> Add VDSO entry with NULL pointer Make ARCH_DLINFO_IA32 check whether the VDSO mapping has been set up for the newly forked process or not. Signed-off-by:
Andy Lutomirski <luto@amacapital.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mathias Krause <minipli@googlemail.com> Link: http://lkml.kernel.org/r/20170410151723.602367196@linutronix.deSigned-off-by:
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Mathias Krause authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit c06989da upstream. vdso_enabled can be set to arbitrary integer values via the kernel command line 'vdso32=' parameter or via 'sysctl abi.vsyscall32'. load_vdso32() only maps VDSO if vdso_enabled == 1, but ARCH_DLINFO_IA32 merily checks for vdso_enabled != 0. As a consequence the AT_SYSINFO_EHDR auxiliary vector for the VDSO_ENTRY is emitted with a NULL pointer which causes a segfault when the application tries to use the VDSO. Restrict the valid arguments on the command line and the sysctl to 0 and 1. Fixes: b0b49f26 ("x86, vdso: Remove compat vdso support") Signed-off-by:
Mathias Krause <minipli@googlemail.com> Acked-by:
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Peter Zijlstra authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit f2200ac3 upstream. When the perf_branch_entry::{in_tx,abort,cycles} fields were added, intel_pmu_lbr_read_32() wasn't updated to initialize them. Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Fixes: 135c5612 ("perf/x86/intel: Support Haswell/v4 LBR format") Signed-off-by:
Ingo Molnar <mingo@kernel.org> Signed-off-by:
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Cameron Gutman authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 53763668 upstream. Signed-off-by:
Cameron Gutman <aicommander@gmail.com> Signed-off-by:
Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by:
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Germano Percossi authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 1fa839b4 upstream. This fixes Continuous Availability when errors during file reopen are encountered. cifs_user_readv and cifs_user_writev would wait for ever if results of cifs_reopen_file are not stored and for later inspection. In fact, results are checked and, in case of errors, a chain of function calls leading to reads and writes to be scheduled in a separate thread is skipped. These threads will wake up the corresponding waiters once reads and writes are done. However, given the return value is not stored, when rc is checked for errors a previous one (always zero) is inspected instead. This leads to pending reads/writes added to the list, making cifs_user_readv and cifs_user_writev wait for ever. Signed-off-by:
Germano Percossi <germano.percossi@citrix.com> Reviewed-by:
Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by:
Steve French <smfrench@gmail.com> Signed-off-by:
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Ilia Mirkin authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit f94773b9 upstream. The NV4A (aka NV44A) is an oddity in the family. It only comes in AGP and PCI varieties, rather than a core PCIE chip with a bridge for AGP/PCI as necessary. As a result, it appears that the MMU is also non-functional. For AGP cards, the vast majority of the NV4A lineup, this worked out since we force AGP cards to use the nv04 mmu. However for PCI variants, this did not work. Switching to the NV04 MMU makes it work like a charm. Thanks to mwk for the suggestion. This should be a no-op for NV4A AGP boards, as they were using it already. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=70388Signed-off-by:
Ilia Mirkin <imirkin@alum.mit.edu> Signed-off-by:
Ben Skeggs <bskeggs@redhat.com> Signed-off-by:
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Ilia Mirkin authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 83bce9c2 upstream. Signed-off-by:
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Kirill A. Shutemov authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 5b7abeae upstream. Yet another instance of the same race. Fix is identical to change_huge_pmd(). See "thp: fix MADV_DONTNEED vs. numa balancing race" for more details. Link: http://lkml.kernel.org/r/20170302151034.27829-5-kirill.shutemov@linux.intel.comSigned-off-by:
Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Signed-off-by:
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Tejun Heo authored
BugLink: http://bugs.launchpad.net/bugs/1687629 commit 77f88796 upstream. Creation of a kthread goes through a couple interlocked stages between the kthread itself and its creator. Once the new kthread starts running, it initializes itself and wakes up the creator. The creator then can further configure the kthread and then let it start doing its job by waking it up. In this configuration-by-creator stage, the creator is the only one that can wake it up but the kthread is visible to userland. When altering the kthread's attributes from userland is allowed, this is fine; however, for cases where CPU affinity is critical, kthread_bind() is used to first disable affinity changes from userland and then set the affinity. This also prevents the kthread from being migrated into non-root cgroups as that can affect the CPU affinity and many other things. Unfortunately, the cgroup side of protection is racy. While the PF_NO_SETAFFINITY flag prevents further migrations, userland can win the race before the creator sets the flag with kthread_bind() and put the kthread in a non-root cgroup, which can lead to all sorts of problems including incorrect CPU affinity and starvation. This bug got triggered by userland which periodically tries to migrate all processes in the root cpuset cgroup to a non-root one. Per-cpu workqueue workers got caught while being created and ended up with incorrected CPU affinity breaking concurrency management and sometimes stalling workqueue execution. This patch adds task->no_cgroup_migration which disallows the task to be migrated by userland. kthreadd starts with the flag set making every child kthread start in the root cgroup with migration disallowed. The flag is cleared after the kthread finishes initialization by which time PF_NO_SETAFFINITY is set if the kthread should stay in the root cgroup. It'd be better to wait for the initialization instead of failing but I couldn't think of a way of implementing that without adding either a new PF flag, or sleeping and retrying from waiting side. Even if userland depends on changing cgroup membership of a kthread, it either has to be synchronized with kthread_create() or periodically repeat, so it's unlikely that this would break anything. v2: Switch to a simpler implementation using a new task_struct bit field suggested by Oleg. Signed-off-by:
Tejun Heo <tj@kernel.org> Suggested-by:
Oleg Nesterov <oleg@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Reported-and-debugged-by:
Chris Mason <clm@fb.com> Signed-off-by:
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- 04 May, 2017 1 commit
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Thadeu Lima de Souza Cascardo authored
Ignore: yes Signed-off-by:
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- 27 Apr, 2017 14 commits
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Thadeu Lima de Souza Cascardo authored
Signed-off-by: -
Roman Pen authored
BugLink: http://bugs.launchpad.net/bugs/1683976 get_disk(),get_gendisk() calls have non explicit side effect: they increase the reference on the disk owner module. The following is the correct sequence how to get a disk reference and to put it: disk = get_gendisk(...); /* use disk */ owner = disk->fops->owner; put_disk(disk); module_put(owner); fs/block_dev.c is aware of this required module_put() call, but f.e. blkg_conf_finish(), which is located in block/blk-cgroup.c, does not put a module reference. To see a leakage in action cgroups throttle config can be used. In the following script I'm removing throttle for /dev/ram0 (actually this is NOP, because throttle was never set for this device): # lsmod | grep brd brd 5175 0 # i=100; while [ $i -gt 0 ]; do echo "1:0 0" > \ /sys/fs/cgroup/blkio/blkio.throttle.read_bps_device; i=$(($i - 1)); \ done # lsmod | grep brd brd 5175 100 Now brd module has 100 references. The issue is fixed by calling module_put() just right away put_disk(). Signed-off-by:
Roman Pen <roman.penyaev@profitbricks.com> Cc: Gi-Oh Kim <gi-oh.kim@profitbricks.com> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by:
Jens Axboe <axboe@fb.com> (cherry picked from commit 39a169b6) Signed-off-by:
Joseph Salisbury <joseph.salisbury@canonical.com> Acked-by:
Kamal Mostafa <kamal@canonical.com> Acked-by:
Colin Ian King <colin.king@canonical.com> Signed-off-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 When device open races with device shutdown, we can get the following oops in scsi_disk_get(): [11863.044351] general protection fault: 0000 [#1] SMP [11863.045561] Modules linked in: scsi_debug xfs libcrc32c netconsole btrfs raid6_pq zlib_deflate lzo_compress xor [last unloaded: loop] [11863.047853] CPU: 3 PID: 13042 Comm: hald-probe-stor Tainted: G W 4.10.0-rc2-xen+ #35 [11863.048030] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [11863.048030] task: ffff88007f438200 task.stack: ffffc90000fd0000 [11863.048030] RIP: 0010:scsi_disk_get+0x43/0x70 [11863.048030] RSP: 0018:ffffc90000fd3a08 EFLAGS: 00010202 [11863.048030] RAX: 6b6b6b6b6b6b6b6b RBX: ffff88007f56d000 RCX: 0000000000000000 [11863.048030] RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff81a8d880 [11863.048030] RBP: ffffc90000fd3a18 R08: 0000000000000000 R09: 0000000000000001 [11863.059217] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000fffffffa [11863.059217] R13: ffff880078872800 R14: ffff880070915540 R15: 000000000000001d [11863.059217] FS: 00007f2611f71800(0000) GS:ffff88007f0c0000(0000) knlGS:0000000000000000 [11863.059217] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [11863.059217] CR2: 000000000060e048 CR3: 00000000778d4000 CR4: 00000000000006e0 [11863.059217] Call Trace: [11863.059217] ? disk_get_part+0x22/0x1f0 [11863.059217] sd_open+0x39/0x130 [11863.059217] __blkdev_get+0x69/0x430 [11863.059217] ? bd_acquire+0x7f/0xc0 [11863.059217] ? bd_acquire+0x96/0xc0 [11863.059217] ? blkdev_get+0x350/0x350 [11863.059217] blkdev_get+0x126/0x350 [11863.059217] ? _raw_spin_unlock+0x2b/0x40 [11863.059217] ? bd_acquire+0x7f/0xc0 [11863.059217] ? blkdev_get+0x350/0x350 [11863.059217] blkdev_open+0x65/0x80 ... As you can see RAX value is already poisoned showing that gendisk we got is already freed. The problem is that get_gendisk() looks up device number in ext_devt_idr and then does get_disk() which does kobject_get() on the disks kobject. However the disk gets removed from ext_devt_idr only in disk_release() (through blk_free_devt()) at which moment it has already 0 refcount and is already on its way to be freed. Indeed we've got a warning from kobject_get() about 0 refcount shortly before the oops. We fix the problem by using kobject_get_unless_zero() in get_disk() so that get_disk() cannot get reference on a disk that is already being freed. Tested-by:
Lekshmi Pillai <lekshmicpillai@in.ibm.com> Reviewed-by:
Jan Kara <jack@suse.cz> Signed-off-by:
Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Signed-off-by:
Tim Gardner <tim.gardner@canonical.com> Acked-by:
Seth Forshee <seth.forshee@canonical.com> Acked-by:
Brad Figg <brad.figg@canonical.com> Signed-off-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 Make the function available for outside use and fortify it against NULL kobject. CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 When block device is closed, we call inode_detach_wb() in __blkdev_put() which sets inode->i_wb to NULL. That is contrary to expectations that inode->i_wb stays valid once set during the whole inode's lifetime and leads to oops in wb_get() in locked_inode_to_wb_and_lock_list() because inode_to_wb() returned NULL. The reason why we called inode_detach_wb() is not valid anymore though. BDI is guaranteed to stay along until we call bdi_put() from bdev_evict_inode() so we can postpone calling inode_detach_wb() to that moment. Also add a warning to catch if someone uses inode_detach_wb() in a dangerous way. Reported-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 Rename cgwb_bdi_destroy() to cgwb_bdi_unregister() as it gets called from bdi_unregister() which is not necessarily called from bdi_destroy() and thus the name is somewhat misleading. Acked-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 Currently we wait for all cgwbs to get released in cgwb_bdi_destroy() (called from bdi_unregister()). That is however unnecessary now when cgwb->bdi is a proper refcounted reference (thus bdi cannot get released before all cgwbs are released) and when cgwb_bdi_destroy() shuts down writeback directly. Acked-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 Currently we waited for all cgwbs to get freed in cgwb_bdi_destroy() which also means that writeback has been shutdown on them. Since this wait is going away, directly shutdown writeback on cgwbs from cgwb_bdi_destroy() to avoid live writeback structures after bdi_unregister() has finished. To make that safe with concurrent shutdown from cgwb_release_workfn(), we also have to make sure wb_shutdown() returns only after the bdi_writeback structure is really shutdown. Acked-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 Currently root wb_writeback structure is added to bdi->wb_list in bdi_init() and never removed. That is different from all other wb_writeback structures which get added to the list when created and removed from it before wb_shutdown(). So move list addition of root bdi_writeback to bdi_register() and list removal of all wb_writeback structures to wb_shutdown(). That way a wb_writeback structure is on bdi->wb_list if and only if it can handle writeback and it will make it easier for us to handle shutdown of all wb_writeback structures in bdi_unregister(). Acked-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 Make wb->bdi a proper refcounted reference to bdi for all bdi_writeback structures except for the one embedded inside struct backing_dev_info. That will allow us to simplify bdi unregistration. Acked-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 congested->bdi pointer is used only to be able to remove congested structure from bdi->cgwb_congested_tree on structure release. Moreover the pointer can become NULL when we unregister the bdi. Rename the field to __bdi and add a comment to make it more explicit this is internal stuff of memcg writeback code and people should not use the field as such use will be likely race prone. We do not bother with converting congested->bdi to a proper refcounted reference. It will be slightly ugly to special-case bdi->wb.congested to avoid effectively a cyclic reference of bdi to itself and the reference gets cleared from bdi_unregister() making it impossible to reference a freed bdi. Acked-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 When disk->fops->open() in __blkdev_get() returns -ERESTARTSYS, we restart the process of opening the block device. However we forget to switch bdev->bd_bdi back to noop_backing_dev_info and as a result bdev inode will be pointing to a stale bdi. Fix the problem by setting bdev->bd_bdi later when __blkdev_get() is already guaranteed to succeed. Acked-by:
Hannes Reinecke <hare@suse.com> Signed-off-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 Commit 165a5e22 "block: Move bdi_unregister() to del_gendisk()" added disk->queue dereference to del_gendisk(). Although del_gendisk() is not supposed to be called without disk->queue valid and blk_unregister_queue() warns in that case, this change will make it oops instead. Return to the old more robust behavior of just warning when del_gendisk() gets called for gendisk with disk->queue being NULL. Reported-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
Omar Sandoval <osandov@fb.com> Signed-off-by:
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Jan Kara authored
BugLink: http://bugs.launchpad.net/bugs/1659111 bdi_writeback_congested structures get created for each blkcg and bdi regardless whether bdi is registered or not. When they are created in unregistered bdi and the request queue (and thus bdi) is then destroyed while blkg still holds reference to bdi_writeback_congested structure, this structure will be referencing freed bdi and last wb_congested_put() will try to remove the structure from already freed bdi. With commit 165a5e22 "block: Move bdi_unregister() to del_gendisk()", SCSI started to destroy bdis without calling bdi_unregister() first (previously it was calling bdi_unregister() even for unregistered bdis) and thus the code detaching bdi_writeback_congested in cgwb_bdi_destroy() was not triggered and we started hitting this use-after-free bug. It is enough to boot a KVM instance with virtio-scsi device to trigger this behavior. Fix the problem by detaching bdi_writeback_congested structures in bdi_exit() instead of bdi_unregister(). This is also more logical as they can get attached to bdi regardless whether it ever got registered or not. Fixes: 165a5e22Signed-off-by:
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