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  1. 12 Apr, 2021 2 commits
    • Vasily Gorbik's avatar
      s390/entry: save the caller of psw_idle · a994eddb
      Vasily Gorbik authored 
      Currently psw_idle does not allocate a stack frame and does not
save its r14 and r15 into the save area. Even though this is valid from
call ABI point of view, because psw_idle does not make any calls
explicitly, in reality psw_idle is an entry point for controlled
transition into serving interrupts. So, in practice, psw_idle stack
frame is analyzed during stack unwinding. Depending on build options
that r14 slot in the save area of psw_idle might either contain a value
saved by previous sibling call or complete garbage.

  [task    0000038000003c28] do_ext_irq+0xd6/0x160
  [task    0000038000003c78] ext_int_handler+0xba/0xe8
  [task   *0000038000003dd8] psw_idle_exit+0x0/0x8 <-- pt_regs
 ([task    0000038000003dd8] 0x0)
  [task    0000038000003e10] default_idle_call+0x42/0x148
  [task    0000038000003e30] do_idle+0xce/0x160
  [task    0000038000003e70] cpu_startup_entry+0x36/0x40
  [task    0000038000003ea0] arch_call_rest_init+0x76/0x80

So, to make a stacktrace nicer and actually point for the real caller of
psw_idle in this frequently occurring case, make psw_idle save its r14.

  [task    0000038000003c28] do_ext_irq+0xd6/0x160
  [task    0000038000003c78] ext_int_handler+0xba/0xe8
  [task   *0000038000003dd8] psw_idle_exit+0x0/0x6 <-- pt_regs
 ([task    0000038000003dd8] arch_cpu_idle+0x3c/0xd0)
  [task    0000038000003e10] default_idle_call+0x42/0x148
  [task    0000038000003e30] do_idle+0xce/0x160
  [task    0000038000003e70] cpu_startup_entry+0x36/0x40
  [task    0000038000003ea0] arch_call_rest_init+0x76/0x80
Reviewed-by: default avatarSven Schnelle <svens@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      a994eddb
    • Vasily Gorbik's avatar
      s390/entry: avoid setting up backchain in ext|io handlers · b74e409e
      Vasily Gorbik authored 
      Currently when interrupt arrives to cpu while in kernel context
INT_HANDLER macro (used for ext_int_handler and io_int_handler)
allocates new stack frame and pt_regs on the kernel stack and
sets up the backchain to jump over the pt_regs to the frame which has
been interrupted. This is not ideal to two reasons:

1. This hides the fact that kernel stack contains interrupt frame in it
   and hence breaks arch_stack_walk_reliable(), which needs to know that to
   guarantee "reliability" and checks that there are no pt_regs on the way.

2. It breaks the backchain unwinder logic, which assumes that the next
   stack frame after an interrupt frame is reliable, while it is not.
   In some cases (when r14 contains garbage) this leads to early unwinding
   termination with an error, instead of marking frame as unreliable
   and continuing.

To address that, only set backchain to 0.

Fixes: 56e62a73 ("s390: convert to generic entry")
Reviewed-by: default avatarSven Schnelle <svens@linux.ibm.com>
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      b74e409e
  3. 07 Apr, 2021 1 commit
  5. 05 Apr, 2021 3 commits
    • Heiko Carstens's avatar
      s390/irq: fix reading of ext_params2 field from lowcore · 85012e76
      Heiko Carstens authored 
      The contents of the ext_params2 field of the lowcore should just be
copied to the pt_regs structure, not dereferenced.

Fixes crashes / program check loops like this:

Krnl PSW : 0404c00180000000 00000000d6d02b3c (do_ext_irq+0x74/0x170)
           R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
Krnl GPRS: 0000000000000000 80000000000b974e 00000000d71abee0 00000000d71abee0
           0000000080030000 000000000000000f 0000000000000000 0000000000000000
           0000000000000001 00000380000bf918 00000000d73ef780 00000380000bf518
           0000000080348000 00000000d6d13350 00000000d6d02b1e 00000380000bf428
Krnl Code: 00000000d6d02b2e: 58100080            l       %r1,128
           00000000d6d02b32: 5010b0a4            st      %r1,164(%r11)
          #00000000d6d02b36: e31001b80104        lg      %r1,4536
          >00000000d6d02b3c: e31010000004        lg      %r1,0(%r1)
           00000000d6d02b42: e310b0a80024        stg     %r1,168(%r11)
           00000000d6d02b48: c01000242270        larl    %r1,00000000d7187028
           00000000d6d02b4e: d5071000b010        clc     0(8,%r1),16(%r11)
           00000000d6d02b54: a784001b            brc     8,00000000d6d02b8a
Call Trace:
 [<00000000d6d02b3c>] do_ext_irq+0x74/0x170
 [<00000000d6d0ea5c>] ext_int_handler+0xc4/0xf4
 [<00000000d621d266>] die+0x106/0x188
 [<00000000d62305b8>] do_no_context+0xc8/0x100
 [<00000000d6d02790>] __do_pgm_check+0xe0/0x1f0
 [<00000000d6d0e950>] pgm_check_handler+0x118/0x160
 [<00000000d6d02b3c>] do_ext_irq+0x74/0x170
 [<00000000d6d0ea5c>] ext_int_handler+0xc4/0xf4
 [<00000000d621d266>] die+0x106/0x188
 [<00000000d62305b8>] do_no_context+0xc8/0x100
 [<00000000d6d02790>] __do_pgm_check+0xe0/0x1f0
 [<00000000d6d0e950>] pgm_check_handler+0x118/0x160
 [<00000000d6d02b3c>] do_ext_irq+0x74/0x170
 [<00000000d6d0ea5c>] ext_int_handler+0xc4/0xf4
 [<0000000000000000>] 0x0
 [<00000000d6d0e57a>] default_idle_call+0x42/0x110
 [<00000000d629856e>] do_idle+0xce/0x160
 [<00000000d62987be>] cpu_startup_entry+0x36/0x40
 [<00000000d621f2f2>] smp_start_secondary+0x82/0x88

Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Fixes: 56e62a73 ("s390: convert to generic entry")
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      85012e76
    • Vasily Gorbik's avatar
      s390/unwind: add machine check handler stack · 08edb968
      Vasily Gorbik authored 
      Fixes: b61b1595 ("s390: add stack for machine check handler")
Signed-off-by: default avatarVasily Gorbik <gor@linux.ibm.com>
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      08edb968
    • Alexander Gordeev's avatar
      s390/cpcmd: fix inline assembly register clobbering · 7a2f9144
      Alexander Gordeev authored 
      Register variables initialized using arithmetic. That leads to
kasan instrumentaton code corrupting the registers contents.
Follow GCC guidlines and use temporary variables for assigning
init values to register variables.

Fixes: 94c12cc7 ("[S390] Inline assembly cleanup.")
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
Acked-by: default avatarIlya Leoshkevich <iii@linux.ibm.com>
Link: https://gcc.gnu.org/onlinedocs/gcc-10.2.0/gcc/Local-Register-Variables.htmlSigned-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      7a2f9144
  7. 28 Mar, 2021 1 commit
  9. 25 Mar, 2021 3 commits
    • Heiko Carstens's avatar
      s390/vdso: fix initializing and updating of vdso_data · 5b43bd18
      Heiko Carstens authored 
      Li Wang reported that clock_gettime(CLOCK_MONOTONIC_RAW, ...) returns
incorrect values when time is provided via vdso instead of system call:

vdso_ts_nsec = 4484351380985507, vdso_ts.tv_sec = 4484351, vdso_ts.tv_nsec = 380985507
sys_ts_nsec  = 1446923235377, sys_ts.tv_sec  = 1446, sys_ts.tv_nsec  = 923235377

Within the s390 specific vdso function __arch_get_hw_counter() reads
tod clock steering values from the arch_data member of the passed in
vdso_data structure.

Problem is that only for the CS_HRES_COARSE vdso_data arch_data is
initialized and gets updated. The CS_RAW specific vdso_data does not
contain any valid tod_clock_steering information, which explains the
different values.

Fix this by initializing and updating all vdso_datas.
Reported-by: default avatarLi Wang <liwang@redhat.com>
Tested-by: default avatarLi Wang <liwang@redhat.com>
Fixes: 1ba2d6c0 ("s390/vdso: simplify __arch_get_hw_counter()")
Link: https://lore.kernel.org/linux-s390/YFnxr1ZlMIOIqjfq@osirisSigned-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      5b43bd18
    • Heiko Carstens's avatar
      s390/vdso: fix tod_steering_delta type · b24bacd6
      Heiko Carstens authored 
      The s390 specific vdso function __arch_get_hw_counter() is supposed to
consider tod clock steering.

If a tod clock steering event happens and the tod clock is set to a
new value __arch_get_hw_counter() will not return the real tod clock
value but slowly drift it from the old delta until the returned value
finally matches the real tod clock value again.

Unfortunately the type of tod_steering_delta unsigned while it is
supposed to be signed. It depends on if tod_steering_delta is negative
or positive in which direction the vdso code drifts the clock value.

Worst case is now that instead of drifting the clock slowly it will
jump into the opposite direction by a factor of two.

Fix this by simply making tod_steering_delta signed.

Fixes: 4bff8cb5 ("s390: convert to GENERIC_VDSO")
Cc: <stable@vger.kernel.org> # 5.10
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      b24bacd6
    • Heiko Carstens's avatar
      s390/vdso: copy tod_steering_delta value to vdso_data page · 72bbc226
      Heiko Carstens authored 
      When converting the vdso assembler code to C it was forgotten to
actually copy the tod_steering_delta value to vdso_data page.

Which in turn means that tod clock steering will not work correctly.

Fix this by simply copying the value whenever it is updated.

Fixes: 4bff8cb5 ("s390: convert to GENERIC_VDSO")
Cc: <stable@vger.kernel.org> # 5.10
Signed-off-by: default avatarHeiko Carstens <hca@linux.ibm.com>
      72bbc226
  11. 21 Mar, 2021 23 commits
  13. 20 Mar, 2021 7 commits
    • Thomas Gleixner's avatar
      genirq: Disable interrupts for force threaded handlers · 81e2073c
      Thomas Gleixner authored 
      With interrupt force threading all device interrupt handlers are invoked
from kernel threads. Contrary to hard interrupt context the invocation only
disables bottom halfs, but not interrupts. This was an oversight back then
because any code like this will have an issue:

thread(irq_A)
  irq_handler(A)
    spin_lock(&foo->lock);

interrupt(irq_B)
  irq_handler(B)
    spin_lock(&foo->lock);

This has been triggered with networking (NAPI vs. hrtimers) and console
drivers where printk() happens from an interrupt which interrupted the
force threaded handler.

Now people noticed and started to change the spin_lock() in the handler to
spin_lock_irqsave() which affects performance or add IRQF_NOTHREAD to the
interrupt request which in turn breaks RT.

Fix the root cause and not the symptom and disable interrupts before
invoking the force threaded handler which preserves the regular semantics
and the usefulness of the interrupt force threading as a general debugging
tool.

For not RT this is not changing much, except that during the execution of
the threaded handler interrupts are delayed until the handler
returns. Vs. scheduling and softirq processing there is no difference.

For RT kernels there is no issue.

Fixes: 8d32a307 ("genirq: Provide forced interrupt threading")
Reported-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarJohan Hovold <johan@kernel.org>
Acked-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20210317143859.513307808@linutronix.de
      81e2073c
    • Linus Torvalds's avatar
      Merge tag 'riscv-for-linus-5.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux · 812da4d3
      Linus Torvalds authored 
      Pull RISC-V fixes from Palmer Dabbelt:
 "A handful of fixes for 5.12:

   - fix the SBI remote fence numbers for hypervisor fences, which had
     been transcribed in the wrong order in Linux. These fences are only
     used with the KVM patches applied.

   - fix a whole host of build warnings, these should have no functional
     change.

   - fix init_resources() to prevent an off-by-one error from causing an
     out-of-bounds array reference. This was manifesting during boot on
     vexriscv.

   - ensure the KASAN mappings are visible before proceeding to use
     them"

* tag 'riscv-for-linus-5.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: Correct SPARSEMEM configuration
  RISC-V: kasan: Declare kasan_shallow_populate() static
  riscv: Ensure page table writes are flushed when initializing KASAN vmalloc
  RISC-V: Fix out-of-bounds accesses in init_resources()
  riscv: Fix compilation error with Canaan SoC
  ftrace: Fix spelling mistake "disabed" -> "disabled"
  riscv: fix bugon.cocci warnings
  riscv: process: Fix no prototype for arch_dup_task_struct
  riscv: ftrace: Use ftrace_get_regs helper
  riscv: process: Fix no prototype for show_regs
  riscv: syscall_table: Reduce W=1 compilation warnings noise
  riscv: time: Fix no prototype for time_init
  riscv: ptrace: Fix no prototype warnings
  riscv: sbi: Fix comment of __sbi_set_timer_v01
  riscv: irq: Fix no prototype warning
  riscv: traps: Fix no prototype warnings
  RISC-V: correct enum sbi_ext_rfence_fid
      812da4d3
    • Linus Torvalds's avatar
      Merge tag '5.12-rc3-smb3' of git://git.samba.org/sfrench/cifs-2.6 · bfdc4aa9
      Linus Torvalds authored 
      Pull cifs fixes from Steve French:
 "Five cifs/smb3 fixes - three for stable, including an important ACL
  fix and security signature fix"

* tag '5.12-rc3-smb3' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix allocation size on newly created files
  cifs: warn and fail if trying to use rootfs without the config option
  fs/cifs/: fix misspellings using codespell tool
  cifs: Fix preauth hash corruption
  cifs: update new ACE pointer after populate_new_aces.
      bfdc4aa9
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · af97713d
      Linus Torvalds authored 
      Pull SCSI fixes from James Bottomley:
 "Eight fixes, all in drivers, all fairly minor either being fixes in
  error legs, memory leaks on teardown, context errors or semantic
  problems"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: mpt3sas: Do not use GFP_KERNEL in atomic context
  scsi: ufs: ufs-mediatek: Correct operator & -> &&
  scsi: sd_zbc: Update write pointer offset cache
  scsi: lpfc: Fix some error codes in debugfs
  scsi: qla2xxx: Fix broken #endif placement
  scsi: st: Fix a use after free in st_open()
  scsi: myrs: Fix a double free in myrs_cleanup()
  scsi: ibmvfc: Free channel_setup_buf during device tear down
      af97713d
    • Linus Torvalds's avatar
      Merge tag 'zonefs-5.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs · 1c273e10
      Linus Torvalds authored 
      Pull zonefs fixes from Damien Le Moal:

 - fix inode write open reference count (Chao)

 - Fix wrong write offset for asynchronous O_APPEND writes (me)

 - Prevent use of sequential zone file as swap files (me)

* tag 'zonefs-5.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/dlemoal/zonefs:
  zonefs: fix to update .i_wr_refcnt correctly in zonefs_open_zone()
  zonefs: Fix O_APPEND async write handling
  zonefs: prevent use of seq files as swap file
      1c273e10
    • Linus Torvalds's avatar
      Merge tag 'block-5.12-2021-03-19' of git://git.kernel.dk/linux-block · d626c692
      Linus Torvalds authored 
      Pull block fixes from Jens Axboe:
 "Just an NVMe pull request this week:

   - fix tag allocation for keep alive

   - fix a unit mismatch for the Write Zeroes limits

   - various TCP transport fixes (Sagi Grimberg, Elad Grupi)

   - fix iosqes and iocqes validation for discovery controllers (Sagi Grimberg)"

* tag 'block-5.12-2021-03-19' of git://git.kernel.dk/linux-block:
  nvmet-tcp: fix kmap leak when data digest in use
  nvmet: don't check iosqes,iocqes for discovery controllers
  nvme-rdma: fix possible hang when failing to set io queues
  nvme-tcp: fix possible hang when failing to set io queues
  nvme-tcp: fix misuse of __smp_processor_id with preemption enabled
  nvme-tcp: fix a NULL deref when receiving a 0-length r2t PDU
  nvme: fix Write Zeroes limitations
  nvme: allocate the keep alive request using BLK_MQ_REQ_NOWAIT
  nvme: merge nvme_keep_alive into nvme_keep_alive_work
  nvme-fabrics: only reserve a single tag
      d626c692
    • Linus Torvalds's avatar
      Merge tag 'io_uring-5.12-2021-03-19' of git://git.kernel.dk/linux-block · 0ada2dad
      Linus Torvalds authored 
      Pull io_uring fixes from Jens Axboe:
 "Quieter week this time, which was both expected and desired. About
  half of the below is fixes for this release, the other half are just
  fixes in general. In detail:

   - Fix the freezing of IO threads, by making the freezer not send them
     fake signals. Make them freezable by default.

   - Like we did for personalities, move the buffer IDR to xarray. Kills
     some code and avoids a use-after-free on teardown.

   - SQPOLL cleanups and fixes (Pavel)

   - Fix linked timeout race (Pavel)

   - Fix potential completion post use-after-free (Pavel)

   - Cleanup and move internal structures outside of general kernel view
     (Stefan)

   - Use MSG_SIGNAL for send/recv from io_uring (Stefan)"

* tag 'io_uring-5.12-2021-03-19' of git://git.kernel.dk/linux-block:
  io_uring: don't leak creds on SQO attach error
  io_uring: use typesafe pointers in io_uring_task
  io_uring: remove structures from include/linux/io_uring.h
  io_uring: imply MSG_NOSIGNAL for send[msg]()/recv[msg]() calls
  io_uring: fix sqpoll cancellation via task_work
  io_uring: add generic callback_head helpers
  io_uring: fix concurrent parking
  io_uring: halt SQO submission on ctx exit
  io_uring: replace sqd rw_semaphore with mutex
  io_uring: fix complete_post use ctx after free
  io_uring: fix ->flags races by linked timeouts
  io_uring: convert io_buffer_idr to XArray
  io_uring: allow IO worker threads to be frozen
  kernel: freezer should treat PF_IO_WORKER like PF_KTHREAD for freezing
      0ada2dad
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