1. 14 Dec, 2021 4 commits
    • Rob Herring's avatar
      arm64: perf: Enable PMU counter userspace access for perf event · 83a7a4d6
      Rob Herring authored
      Arm PMUs can support direct userspace access of counters which allows for
      low overhead (i.e. no syscall) self-monitoring of tasks. The same feature
      exists on x86 called 'rdpmc'. Unlike x86, userspace access will only be
      enabled for thread bound events. This could be extended if needed, but
      simplifies the implementation and reduces the chances for any
      information leaks (which the x86 implementation suffers from).
      
      PMU EL0 access will be enabled when an event with userspace access is
      part of the thread's context. This includes when the event is not
      scheduled on the PMU. There's some additional overhead clearing
      dirty counters when access is enabled in order to prevent leaking
      disabled counter data from other tasks.
      
      Unlike x86, enabling of userspace access must be requested with a new
      attr bit: config1:1. If the user requests userspace access with 64-bit
      counters, then the event open will fail if the h/w doesn't support
      64-bit counters. Chaining is not supported with userspace access. The
      modes for config1 are as follows:
      
      config1 = 0 : user access disabled and always 32-bit
      config1 = 1 : user access disabled and always 64-bit (using chaining if needed)
      config1 = 2 : user access enabled and always 32-bit
      config1 = 3 : user access enabled and always 64-bit
      
      Based on work by Raphael Gault <raphael.gault@arm.com>, but has been
      completely re-written.
      
      Cc: Will Deacon <will@kernel.org>
      Cc: Mark Rutland <mark.rutland@arm.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: linux-arm-kernel@lists.infradead.org
      Cc: linux-perf-users@vger.kernel.org
      Signed-off-by: default avatarRob Herring <robh@kernel.org>
      Link: https://lore.kernel.org/r/20211208201124.310740-5-robh@kernel.org
      [will: Made armv8pmu_proc_user_access_handler() static]
      Signed-off-by: default avatarWill Deacon <will@kernel.org>
      83a7a4d6
    • Rob Herring's avatar
      arm64: perf: Add userspace counter access disable switch · e2012600
      Rob Herring authored
      Like x86, some users may want to disable userspace PMU counter
      altogether. Add a sysctl 'perf_user_access' file to control userspace
      counter access. The default is '0' which is disabled. Writing '1'
      enables access.
      
      Note that x86 supports globally enabling user access by writing '2' to
      /sys/bus/event_source/devices/cpu/rdpmc. As there's not existing
      userspace support to worry about, this shouldn't be necessary for Arm.
      It could be added later if the need arises.
      
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Catalin Marinas <catalin.marinas@arm.com>
      Cc: linux-perf-users@vger.kernel.org
      Acked-by: default avatarWill Deacon <will@kernel.org>
      Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
      Signed-off-by: default avatarRob Herring <robh@kernel.org>
      Link: https://lore.kernel.org/r/20211208201124.310740-4-robh@kernel.orgSigned-off-by: default avatarWill Deacon <will@kernel.org>
      e2012600
    • Rob Herring's avatar
      perf: Add a counter for number of user access events in context · 82ff0c02
      Rob Herring authored
      On arm64, user space counter access will be controlled differently
      compared to x86. On x86, access in the strictest mode is enabled for all
      tasks in an MM when any event is mmap'ed. For arm64, access is
      explicitly requested for an event and only enabled when the event's
      context is active. This avoids hooks into the arch context switch code
      and gives better control of when access is enabled.
      
      In order to configure user space access when the PMU is enabled, it is
      necessary to know if any event (currently active or not) in the current
      context has user space accessed enabled. Add a counter similar to other
      counters in the context to avoid walking the event list every time.
      Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarRob Herring <robh@kernel.org>
      Link: https://lore.kernel.org/r/20211208201124.310740-3-robh@kernel.orgSigned-off-by: default avatarWill Deacon <will@kernel.org>
      82ff0c02
    • Rob Herring's avatar
      x86: perf: Move RDPMC event flag to a common definition · 369461ce
      Rob Herring authored
      In preparation to enable user counter access on arm64 and to move some
      of the user access handling to perf core, create a common event flag for
      user counter access and convert x86 to use it.
      
      Since the architecture specific flags start at the LSB, starting at the
      MSB for common flags.
      
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Kan Liang <kan.liang@linux.intel.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: x86@kernel.org
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: linux-perf-users@vger.kernel.org
      Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarRob Herring <robh@kernel.org>
      Link: https://lore.kernel.org/r/20211208201124.310740-2-robh@kernel.orgSigned-off-by: default avatarWill Deacon <will@kernel.org>
      369461ce
  2. 28 Nov, 2021 8 commits
  3. 27 Nov, 2021 17 commits
    • Linus Torvalds's avatar
      Merge tag '5.16-rc2-ksmbd-fixes' of git://git.samba.org/ksmbd · 3498e7f2
      Linus Torvalds authored
      Pull ksmbd fixes from Steve French:
       "Five ksmbd server fixes, four of them for stable:
      
         - memleak fix
      
         - fix for default data stream on filesystems that don't support xattr
      
         - error logging fix
      
         - session setup fix
      
         - minor doc cleanup"
      
      * tag '5.16-rc2-ksmbd-fixes' of git://git.samba.org/ksmbd:
        ksmbd: fix memleak in get_file_stream_info()
        ksmbd: contain default data stream even if xattr is empty
        ksmbd: downgrade addition info error msg to debug in smb2_get_info_sec()
        docs: filesystem: cifs: ksmbd: Fix small layout issues
        ksmbd: Fix an error handling path in 'smb2_sess_setup()'
      3498e7f2
    • Guenter Roeck's avatar
      vmxnet3: Use generic Kconfig option for page size limit · 00169a92
      Guenter Roeck authored
      Use the architecture independent Kconfig option PAGE_SIZE_LESS_THAN_64KB
      to indicate that VMXNET3 requires a page size smaller than 64kB.
      Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      00169a92
    • Guenter Roeck's avatar
      fs: ntfs: Limit NTFS_RW to page sizes smaller than 64k · 4eec7faf
      Guenter Roeck authored
      NTFS_RW code allocates page size dependent arrays on the stack. This
      results in build failures if the page size is 64k or larger.
      
        fs/ntfs/aops.c: In function 'ntfs_write_mst_block':
        fs/ntfs/aops.c:1311:1: error:
      	the frame size of 2240 bytes is larger than 2048 bytes
      
      Since commit f22969a6 ("powerpc/64s: Default to 64K pages for 64 bit
      book3s") this affects ppc:allmodconfig builds, but other architectures
      supporting page sizes of 64k or larger are also affected.
      
      Increasing the maximum frame size for affected architectures just to
      silence this error does not really help.  The frame size would have to
      be set to a really large value for 256k pages.  Also, a large frame size
      could potentially result in stack overruns in this code and elsewhere
      and is therefore not desirable.  Make NTFS_RW dependent on page sizes
      smaller than 64k instead.
      Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Cc: Anton Altaparmakov <anton@tuxera.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4eec7faf
    • Guenter Roeck's avatar
      arch: Add generic Kconfig option indicating page size smaller than 64k · 1f0e290c
      Guenter Roeck authored
      NTFS_RW and VMXNET3 require a page size smaller than 64kB.  Add generic
      Kconfig option for use outside architecture code to avoid architecture
      specific Kconfig options in that code.
      Suggested-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Cc: Anton Altaparmakov <anton@tuxera.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1f0e290c
    • Steven Rostedt (VMware)'s avatar
      tracing: Test the 'Do not trace this pid' case in create event · 27ff768f
      Steven Rostedt (VMware) authored
      When creating a new event (via a module, kprobe, eprobe, etc), the
      descriptors that are created must add flags for pid filtering if an
      instance has pid filtering enabled, as the flags are used at the time the
      event is executed to know if pid filtering should be done or not.
      
      The "Only trace this pid" case was added, but a cut and paste error made
      that case checked twice, instead of checking the "Trace all but this pid"
      case.
      
      Link: https://lore.kernel.org/all/202111280401.qC0z99JB-lkp@intel.com/
      
      Fixes: 6cb20650 ("tracing: Check pid filtering when creating events")
      Reported-by: default avatarkernel test robot <lkp@intel.com>
      Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
      27ff768f
    • Linus Torvalds's avatar
      Merge tag 'xfs-5.16-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux · 4f0dda35
      Linus Torvalds authored
      Pull xfs fixes from Darrick Wong:
       "Fixes for a resource leak and a build robot complaint about totally
        dead code:
      
         - Fix buffer resource leak that could lead to livelock on corrupt fs.
      
         - Remove unused function xfs_inew_wait to shut up the build robots"
      
      * tag 'xfs-5.16-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
        xfs: remove xfs_inew_wait
        xfs: Fix the free logic of state in xfs_attr_node_hasname
      4f0dda35
    • Linus Torvalds's avatar
      Merge tag 'iomap-5.16-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux · adfb743a
      Linus Torvalds authored
      Pull iomap fixes from Darrick Wong:
       "A single iomap bug fix and a cleanup for 5.16-rc2.
      
        The bug fix changes how iomap deals with reading from an inline data
        region -- whereas the current code (incorrectly) lets the iomap read
        iter try for more bytes after reading the inline region (which zeroes
        the rest of the page!) and hopes the next iteration terminates, we
        surveyed the inlinedata implementations and realized that all
        inlinedata implementations also require that the inlinedata region end
        at EOF, so we can simply terminate the read.
      
        The second patch documents these assumptions in the code so that
        they're not subtle implications anymore, and cleans up some of the
        grosser parts of that function.
      
        Summary:
      
         - Fix an accounting problem where unaligned inline data reads can run
           off the end of the read iomap iterator. iomap has historically
           required that inline data mappings only exist at the end of a file,
           though this wasn't documented anywhere.
      
         - Document iomap_read_inline_data and change its return type to be
           appropriate for the information that it's actually returning"
      
      * tag 'iomap-5.16-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
        iomap: iomap_read_inline_data cleanup
        iomap: Fix inline extent handling in iomap_readpage
      adfb743a
    • Linus Torvalds's avatar
      Merge tag 'trace-v5.16-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace · 86155d6b
      Linus Torvalds authored
      Pull tracing fixes from Steven Rostedt:
       "Two fixes to event pid filtering:
      
         - Make sure newly created events reflect the current state of pid
           filtering
      
         - Take pid filtering into account when recording trigger events.
           (Also clean up the if statement to be cleaner)"
      
      * tag 'trace-v5.16-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
        tracing: Fix pid filtering when triggers are attached
        tracing: Check pid filtering when creating events
      86155d6b
    • Linus Torvalds's avatar
      Merge tag 'io_uring-5.16-2021-11-27' of git://git.kernel.dk/linux-block · 86799cdf
      Linus Torvalds authored
      Pull more io_uring fixes from Jens Axboe:
       "The locking fixup that was applied earlier this rc has both a deadlock
        and IRQ safety issue, let's get that ironed out before -rc3. This
        contains:
      
         - Link traversal locking fix (Pavel)
      
         - Cancelation fix (Pavel)
      
         - Relocate cond_resched() for huge buffer chain freeing, avoiding a
           softlockup warning (Ye)
      
         - Fix timespec validation (Ye)"
      
      * tag 'io_uring-5.16-2021-11-27' of git://git.kernel.dk/linux-block:
        io_uring: Fix undefined-behaviour in io_issue_sqe
        io_uring: fix soft lockup when call __io_remove_buffers
        io_uring: fix link traversal locking
        io_uring: fail cancellation for EXITING tasks
      86799cdf
    • Linus Torvalds's avatar
      Merge tag 'block-5.16-2021-11-27' of git://git.kernel.dk/linux-block · 650c8edf
      Linus Torvalds authored
      Pull more block fixes from Jens Axboe:
       "Turns out that the flushing out of pending fixes before the
        Thanksgiving break didn't quite work out in terms of timing, so here's
        a followup set of fixes:
      
         - rq_qos_done() should be called regardless of whether or not we're
           the final put of the request, it's not related to the freeing of
           the state. This fixes an IO stall with wbt that a few users have
           reported, a regression in this release.
      
         - Only define zram_wb_devops if it's used, fixing a compilation
           warning for some compilers"
      
      * tag 'block-5.16-2021-11-27' of git://git.kernel.dk/linux-block:
        zram: only make zram_wb_devops for CONFIG_ZRAM_WRITEBACK
        block: call rq_qos_done() before ref check in batch completions
      650c8edf
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · 9e9fbe44
      Linus Torvalds authored
      Pull SCSI fixes from James Bottomley:
       "Twelve fixes, eleven in drivers (target, qla2xx, scsi_debug, mpt3sas,
        ufs). The core fix is a minor correction to the previous state update
        fix for the iscsi daemons"
      
      * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
        scsi: scsi_debug: Zero clear zones at reset write pointer
        scsi: core: sysfs: Fix setting device state to SDEV_RUNNING
        scsi: scsi_debug: Sanity check block descriptor length in resp_mode_select()
        scsi: target: configfs: Delete unnecessary checks for NULL
        scsi: target: core: Use RCU helpers for INQUIRY t10_alua_tg_pt_gp
        scsi: mpt3sas: Fix incorrect system timestamp
        scsi: mpt3sas: Fix system going into read-only mode
        scsi: mpt3sas: Fix kernel panic during drive powercycle test
        scsi: ufs: ufs-mediatek: Add put_device() after of_find_device_by_node()
        scsi: scsi_debug: Fix type in min_t to avoid stack OOB
        scsi: qla2xxx: edif: Fix off by one bug in qla_edif_app_getfcinfo()
        scsi: ufs: ufshpb: Fix warning in ufshpb_set_hpb_read_to_upiu()
      9e9fbe44
    • Linus Torvalds's avatar
      Merge tag 'nfs-for-5.16-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs · 74139277
      Linus Torvalds authored
      Pull NFS client fixes from Trond Myklebust:
       "Highlights include:
      
        Stable fixes:
      
         - NFSv42: Fix pagecache invalidation after COPY/CLONE
      
        Bugfixes:
      
         - NFSv42: Don't fail clone() just because the server failed to return
           post-op attributes
      
         - SUNRPC: use different lockdep keys for INET6 and LOCAL
      
         - NFSv4.1: handle NFS4ERR_NOSPC from CREATE_SESSION
      
         - SUNRPC: fix header include guard in trace header"
      
      * tag 'nfs-for-5.16-2' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
        SUNRPC: use different lock keys for INET6 and LOCAL
        sunrpc: fix header include guard in trace header
        NFSv4.1: handle NFS4ERR_NOSPC by CREATE_SESSION
        NFSv42: Fix pagecache invalidation after COPY/CLONE
        NFS: Add a tracepoint to show the results of nfs_set_cache_invalid()
        NFSv42: Don't fail clone() unless the OP_CLONE operation failed
      74139277
    • Linus Torvalds's avatar
      Merge tag 'erofs-for-5.16-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs · 52dc4c64
      Linus Torvalds authored
      Pull erofs fix from Gao Xiang:
       "Fix an ABBA deadlock introduced by XArray conversion"
      
      * tag 'erofs-for-5.16-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
        erofs: fix deadlock when shrink erofs slab
      52dc4c64
    • Linus Torvalds's avatar
      Merge tag 'powerpc-5.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux · 7b65b798
      Linus Torvalds authored
      Pull powerpc fixes from Michael Ellerman:
       "Fix KVM using a Power9 instruction on earlier CPUs, which could lead
        to the host SLB being incorrectly invalidated and a subsequent host
        crash.
      
        Fix kernel hardlockup on vmap stack overflow on 32-bit.
      
        Thanks to Christophe Leroy, Nicholas Piggin, and Fabiano Rosas"
      
      * tag 'powerpc-5.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
        powerpc/32: Fix hardlockup on vmap stack overflow
        KVM: PPC: Book3S HV: Prevent POWER7/8 TLB flush flushing SLB
      7b65b798
    • Linus Torvalds's avatar
      Merge tag 'mips-fixes_5.16_2' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux · 6be08803
      Linus Torvalds authored
      Pull MIPS fixes from Thomas Bogendoerfer:
      
       - build fix for ZSTD enabled configs
      
       - fix for preempt warning
      
       - fix for loongson FTLB detection
      
       - fix for page table level selection
      
      * tag 'mips-fixes_5.16_2' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
        MIPS: use 3-level pgtable for 64KB page size on MIPS_VA_BITS_48
        MIPS: loongson64: fix FTLB configuration
        MIPS: Fix using smp_processor_id() in preemptible in show_cpuinfo()
        MIPS: boot/compressed/: add __ashldi3 to target for ZSTD compression
      6be08803
    • Ye Bin's avatar
      io_uring: Fix undefined-behaviour in io_issue_sqe · f6223ff7
      Ye Bin authored
      We got issue as follows:
      ================================================================================
      UBSAN: Undefined behaviour in ./include/linux/ktime.h:42:14
      signed integer overflow:
      -4966321760114568020 * 1000000000 cannot be represented in type 'long long int'
      CPU: 1 PID: 2186 Comm: syz-executor.2 Not tainted 4.19.90+ #12
      Hardware name: linux,dummy-virt (DT)
      Call trace:
       dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78
       show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
       __dump_stack lib/dump_stack.c:77 [inline]
       dump_stack+0x170/0x1dc lib/dump_stack.c:118
       ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161
       handle_overflow+0x188/0x1dc lib/ubsan.c:192
       __ubsan_handle_mul_overflow+0x34/0x44 lib/ubsan.c:213
       ktime_set include/linux/ktime.h:42 [inline]
       timespec64_to_ktime include/linux/ktime.h:78 [inline]
       io_timeout fs/io_uring.c:5153 [inline]
       io_issue_sqe+0x42c8/0x4550 fs/io_uring.c:5599
       __io_queue_sqe+0x1b0/0xbc0 fs/io_uring.c:5988
       io_queue_sqe+0x1ac/0x248 fs/io_uring.c:6067
       io_submit_sqe fs/io_uring.c:6137 [inline]
       io_submit_sqes+0xed8/0x1c88 fs/io_uring.c:6331
       __do_sys_io_uring_enter fs/io_uring.c:8170 [inline]
       __se_sys_io_uring_enter fs/io_uring.c:8129 [inline]
       __arm64_sys_io_uring_enter+0x490/0x980 fs/io_uring.c:8129
       invoke_syscall arch/arm64/kernel/syscall.c:53 [inline]
       el0_svc_common+0x374/0x570 arch/arm64/kernel/syscall.c:121
       el0_svc_handler+0x190/0x260 arch/arm64/kernel/syscall.c:190
       el0_svc+0x10/0x218 arch/arm64/kernel/entry.S:1017
      ================================================================================
      
      As ktime_set only judge 'secs' if big than KTIME_SEC_MAX, but if we pass
      negative value maybe lead to overflow.
      To address this issue, we must check if 'sec' is negative.
      Signed-off-by: default avatarYe Bin <yebin10@huawei.com>
      Link: https://lore.kernel.org/r/20211118015907.844807-1-yebin10@huawei.comSigned-off-by: default avatarJens Axboe <axboe@kernel.dk>
      f6223ff7
    • Ye Bin's avatar
      io_uring: fix soft lockup when call __io_remove_buffers · 1d0254e6
      Ye Bin authored
      I got issue as follows:
      [ 567.094140] __io_remove_buffers: [1]start ctx=0xffff8881067bf000 bgid=65533 buf=0xffff8881fefe1680
      [  594.360799] watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [kworker/u32:5:108]
      [  594.364987] Modules linked in:
      [  594.365405] irq event stamp: 604180238
      [  594.365906] hardirqs last  enabled at (604180237): [<ffffffff93fec9bd>] _raw_spin_unlock_irqrestore+0x2d/0x50
      [  594.367181] hardirqs last disabled at (604180238): [<ffffffff93fbbadb>] sysvec_apic_timer_interrupt+0xb/0xc0
      [  594.368420] softirqs last  enabled at (569080666): [<ffffffff94200654>] __do_softirq+0x654/0xa9e
      [  594.369551] softirqs last disabled at (569080575): [<ffffffff913e1d6a>] irq_exit_rcu+0x1ca/0x250
      [  594.370692] CPU: 2 PID: 108 Comm: kworker/u32:5 Tainted: G            L    5.15.0-next-20211112+ #88
      [  594.371891] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014
      [  594.373604] Workqueue: events_unbound io_ring_exit_work
      [  594.374303] RIP: 0010:_raw_spin_unlock_irqrestore+0x33/0x50
      [  594.375037] Code: 48 83 c7 18 53 48 89 f3 48 8b 74 24 10 e8 55 f5 55 fd 48 89 ef e8 ed a7 56 fd 80 e7 02 74 06 e8 43 13 7b fd fb bf 01 00 00 00 <e8> f8 78 474
      [  594.377433] RSP: 0018:ffff888101587a70 EFLAGS: 00000202
      [  594.378120] RAX: 0000000024030f0d RBX: 0000000000000246 RCX: 1ffffffff2f09106
      [  594.379053] RDX: 0000000000000000 RSI: ffffffff9449f0e0 RDI: 0000000000000001
      [  594.379991] RBP: ffffffff9586cdc0 R08: 0000000000000001 R09: fffffbfff2effcab
      [  594.380923] R10: ffffffff977fe557 R11: fffffbfff2effcaa R12: ffff8881b8f3def0
      [  594.381858] R13: 0000000000000246 R14: ffff888153a8b070 R15: 0000000000000000
      [  594.382787] FS:  0000000000000000(0000) GS:ffff888399c00000(0000) knlGS:0000000000000000
      [  594.383851] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
      [  594.384602] CR2: 00007fcbe71d2000 CR3: 00000000b4216000 CR4: 00000000000006e0
      [  594.385540] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
      [  594.386474] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
      [  594.387403] Call Trace:
      [  594.387738]  <TASK>
      [  594.388042]  find_and_remove_object+0x118/0x160
      [  594.389321]  delete_object_full+0xc/0x20
      [  594.389852]  kfree+0x193/0x470
      [  594.390275]  __io_remove_buffers.part.0+0xed/0x147
      [  594.390931]  io_ring_ctx_free+0x342/0x6a2
      [  594.392159]  io_ring_exit_work+0x41e/0x486
      [  594.396419]  process_one_work+0x906/0x15a0
      [  594.399185]  worker_thread+0x8b/0xd80
      [  594.400259]  kthread+0x3bf/0x4a0
      [  594.401847]  ret_from_fork+0x22/0x30
      [  594.402343]  </TASK>
      
      Message from syslogd@localhost at Nov 13 09:09:54 ...
      kernel:watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [kworker/u32:5:108]
      [  596.793660] __io_remove_buffers: [2099199]start ctx=0xffff8881067bf000 bgid=65533 buf=0xffff8881fefe1680
      
      We can reproduce this issue by follow syzkaller log:
      r0 = syz_io_uring_setup(0x401, &(0x7f0000000300), &(0x7f0000003000/0x2000)=nil, &(0x7f0000ff8000/0x4000)=nil, &(0x7f0000000280)=<r1=>0x0, &(0x7f0000000380)=<r2=>0x0)
      sendmsg$ETHTOOL_MSG_FEATURES_SET(0xffffffffffffffff, &(0x7f0000003080)={0x0, 0x0, &(0x7f0000003040)={&(0x7f0000000040)=ANY=[], 0x18}}, 0x0)
      syz_io_uring_submit(r1, r2, &(0x7f0000000240)=@IORING_OP_PROVIDE_BUFFERS={0x1f, 0x5, 0x0, 0x401, 0x1, 0x0, 0x100, 0x0, 0x1, {0xfffd}}, 0x0)
      io_uring_enter(r0, 0x3a2d, 0x0, 0x0, 0x0, 0x0)
      
      The reason above issue  is 'buf->list' has 2,100,000 nodes, occupied cpu lead
      to soft lockup.
      To solve this issue, we need add schedule point when do while loop in
      '__io_remove_buffers'.
      After add  schedule point we do regression, get follow data.
      [  240.141864] __io_remove_buffers: [1]start ctx=0xffff888170603000 bgid=65533 buf=0xffff8881116fcb00
      [  268.408260] __io_remove_buffers: [1]start ctx=0xffff8881b92d2000 bgid=65533 buf=0xffff888130c83180
      [  275.899234] __io_remove_buffers: [2099199]start ctx=0xffff888170603000 bgid=65533 buf=0xffff8881116fcb00
      [  296.741404] __io_remove_buffers: [1]start ctx=0xffff8881b659c000 bgid=65533 buf=0xffff8881010fe380
      [  305.090059] __io_remove_buffers: [2099199]start ctx=0xffff8881b92d2000 bgid=65533 buf=0xffff888130c83180
      [  325.415746] __io_remove_buffers: [1]start ctx=0xffff8881b92d1000 bgid=65533 buf=0xffff8881a17d8f00
      [  333.160318] __io_remove_buffers: [2099199]start ctx=0xffff8881b659c000 bgid=65533 buf=0xffff8881010fe380
      ...
      
      Fixes:8bab4c09("io_uring: allow conditional reschedule for intensive iterators")
      Signed-off-by: default avatarYe Bin <yebin10@huawei.com>
      Link: https://lore.kernel.org/r/20211122024737.2198530-1-yebin10@huawei.comSigned-off-by: default avatarJens Axboe <axboe@kernel.dk>
      1d0254e6
  4. 26 Nov, 2021 11 commits