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  8. Nov 28, 2021
  9. Nov 27, 2021
    • 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.com
      
      
      Signed-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.com
      
      
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      1d0254e6
    • Steven Rostedt (VMware)'s avatar
      tracing: Fix pid filtering when triggers are attached · a55f224f
      Steven Rostedt (VMware) authored
      If a event is filtered by pid and a trigger that requires processing of
      the event to happen is a attached to the event, the discard portion does
      not take the pid filtering into account, and the event will then be
      recorded when it should not have been.
      
      Cc: stable@vger.kernel.org
      Fixes: 3fdaf80f
      
       ("tracing: Implement event pid filtering")
      Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
      a55f224f