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Else there may be magic numbers in /sys/kernel/debug/block/*/state. Signed-off-by: Hou Tao <houtao1@huawei.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make blk_ksm_destroy() use the kvfree_sensitive() function (which was introduced in v5.8-rc1) instead of open-coding it. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
So that the target task will exit the wait_event_interruptible-like loop and call task_work_run() asap. The patch turns "bool notify" into 0,TWA_RESUME,TWA_SIGNAL enum, the new TWA_SIGNAL flag implies signal_wake_up(). However, it needs to avoid the race with recalc_sigpending(), so the patch also adds the new JOBCTL_TASK_WORK bit included in JOBCTL_PENDING_MASK. TODO: once this patch is merged we need to change all current users of task_work_add(notify = true) to use TWA_RESUME. Cc: stable@vger.kernel.org # v5.7 Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Since 5.7, we've been using task_work to trigger async running of requests in the context of the original task. This generally works great, but there's a case where if the task is currently blocked in the kernel waiting on a condition to become true, it won't process task_work. Even though the task is woken, it just checks whatever condition it's waiting on, and goes back to sleep if it's still false. This is a problem if that very condition only becomes true when that task_work is run. An example of that is the task registering an eventfd with io_uring, and it's now blocked waiting on an eventfd read. That read could depend on a completion event, and that completion event won't get trigged until task_work has been run. Use the TWA_SIGNAL notification for task_work, so that we ensure that the task always runs the work when queued. Cc: stable@vger.kernel.org # v5.7 Signed-off-by: Jens Axboe <axboe@kernel.dk>
Else there will be memory leak if alloc_disk() fails. Fixes: 6a27b65 ("block: virtio-blk: support multi virt queues per virtio-blk device") Signed-off-by: Hou Tao <houtao1@huawei.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull io_uring fixes from Jens Axboe: "One fix in here, for a regression in 5.7 where a task is waiting in the kernel for a condition, but that condition won't become true until task_work is run. And the task_work can't be run exactly because the task is waiting in the kernel, so we'll never make any progress. One example of that is registering an eventfd and queueing io_uring work, and then the task goes and waits in eventfd read with the expectation that it'll get woken (and read an event) when the io_uring request completes. The io_uring request is finished through task_work, which won't get run while the task is looping in eventfd read" * tag 'io_uring-5.8-2020-07-01' of git://git.kernel.dk/linux-block: io_uring: use signal based task_work running task_work: teach task_work_add() to do signal_wake_up()
Pull block fixes from Jens Axboe: - Use kvfree_sensitive() for the block keyslot free (Eric) - Sync blk-mq debugfs flags (Hou) - Memory leak fix in virtio-blk error path (Hou) * tag 'block-5.8-2020-07-01' of git://git.kernel.dk/linux-block: virtio-blk: free vblk-vqs in error path of virtblk_probe() block/keyslot-manager: use kvfree_sensitive() blk-mq-debugfs: update blk_queue_flag_name[] accordingly for new flags
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Jul 3, 2021
The "auxtrace_info" and "auxtrace" functions are not set in "tool" member of
"annotate". As a result, perf annotate does not support parsing itrace data.
Before:
# perf record -e arm_spe_0/branch_filter=1/ -a sleep 1
[ perf record: Woken up 9 times to write data ]
[ perf record: Captured and wrote 20.874 MB perf.data ]
# perf annotate --stdio
Error:
The perf.data data has no samples!
Solution:
1. Add itrace options in help,
2. Set hook functions of "id_index", "auxtrace_info" and "auxtrace" in perf_tool.
After:
# perf record --all-user -e arm_spe_0/branch_filter=1/ ls
Couldn't synthesize bpf events.
perf.data
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.010 MB perf.data ]
# perf annotate --stdio
Percent | Source code & Disassembly of libc-2.28.so for branch-miss (1 samples, percent: local period)
------------------------------------------------------------------------------------------------------------
:
:
:
: Disassembly of section .text:
:
: 0000000000066180 <__getdelim@@GLIBC_2.17>:
0.00 : 66180: stp x29, x30, [sp, #-96]!
0.00 : 66184: cmp x0, #0x0
0.00 : 66188: ccmp x1, #0x0, #0x4, ne // ne = any
0.00 : 6618c: mov x29, sp
0.00 : 66190: stp x24, x25, [sp, #56]
0.00 : 66194: stp x26, x27, [sp, #72]
0.00 : 66198: str x28, [sp, #88]
0.00 : 6619c: b.eq 66450 <__getdelim@@GLIBC_2.17+0x2d0> // b.none
0.00 : 661a0: stp x22, x23, [x29, #40]
0.00 : 661a4: mov x22, x1
0.00 : 661a8: ldr w1, [x3]
0.00 : 661ac: mov w23, w2
0.00 : 661b0: stp x20, x21, [x29, #24]
0.00 : 661b4: mov x20, x3
0.00 : 661b8: mov x21, x0
0.00 : 661bc: tbnz w1, #15, 66360 <__getdelim@@GLIBC_2.17+0x1e0>
0.00 : 661c0: ldr x0, [x3, #136]
0.00 : 661c4: ldr x2, [x0, #8]
0.00 : 661c8: str x19, [x29, #16]
0.00 : 661cc: mrs x19, tpidr_el0
0.00 : 661d0: sub x19, x19, #0x700
0.00 : 661d4: cmp x2, x19
0.00 : 661d8: b.eq 663f0 <__getdelim@@GLIBC_2.17+0x270> // b.none
0.00 : 661dc: mov w1, #0x1 // #1
0.00 : 661e0: ldaxr w2, [x0]
0.00 : 661e4: cmp w2, #0x0
0.00 : 661e8: b.ne 661f4 <__getdelim@@GLIBC_2.17+0x74> // b.any
0.00 : 661ec: stxr w3, w1, [x0]
0.00 : 661f0: cbnz w3, 661e0 <__getdelim@@GLIBC_2.17+0x60>
0.00 : 661f4: b.ne 66448 <__getdelim@@GLIBC_2.17+0x2c8> // b.any
0.00 : 661f8: ldr x0, [x20, #136]
0.00 : 661fc: ldr w1, [x20]
0.00 : 66200: ldr w2, [x0, #4]
0.00 : 66204: str x19, [x0, #8]
0.00 : 66208: add w2, w2, #0x1
0.00 : 6620c: str w2, [x0, #4]
0.00 : 66210: tbnz w1, #5, 66388 <__getdelim@@GLIBC_2.17+0x208>
0.00 : 66214: ldr x19, [x29, #16]
0.00 : 66218: ldr x0, [x21]
0.00 : 6621c: cbz x0, 66228 <__getdelim@@GLIBC_2.17+0xa8>
0.00 : 66220: ldr x0, [x22]
0.00 : 66224: cbnz x0, 6623c <__getdelim@@GLIBC_2.17+0xbc>
0.00 : 66228: mov x0, #0x78 // #120
0.00 : 6622c: str x0, [x22]
0.00 : 66230: bl 20710 <malloc@plt>
0.00 : 66234: str x0, [x21]
0.00 : 66238: cbz x0, 66428 <__getdelim@@GLIBC_2.17+0x2a8>
0.00 : 6623c: ldr x27, [x20, #8]
0.00 : 66240: str x19, [x29, #16]
0.00 : 66244: ldr x19, [x20, #16]
0.00 : 66248: sub x19, x19, x27
0.00 : 6624c: cmp x19, #0x0
0.00 : 66250: b.le 66398 <__getdelim@@GLIBC_2.17+0x218>
0.00 : 66254: mov x25, #0x0 // #0
0.00 : 66258: b 662d8 <__getdelim@@GLIBC_2.17+0x158>
0.00 : 6625c: nop
0.00 : 66260: add x24, x19, x25
0.00 : 66264: ldr x3, [x22]
0.00 : 66268: add x26, x24, #0x1
0.00 : 6626c: ldr x0, [x21]
0.00 : 66270: cmp x3, x26
0.00 : 66274: b.cs 6629c <__getdelim@@GLIBC_2.17+0x11c> // b.hs, b.nlast
0.00 : 66278: lsl x3, x3, #1
0.00 : 6627c: cmp x3, x26
0.00 : 66280: csel x26, x3, x26, cs // cs = hs, nlast
0.00 : 66284: mov x1, x26
0.00 : 66288: bl 206f0 <realloc@plt>
0.00 : 6628c: cbz x0, 66438 <__getdelim@@GLIBC_2.17+0x2b8>
0.00 : 66290: str x0, [x21]
0.00 : 66294: ldr x27, [x20, #8]
0.00 : 66298: str x26, [x22]
0.00 : 6629c: mov x2, x19
0.00 : 662a0: mov x1, x27
0.00 : 662a4: add x0, x0, x25
0.00 : 662a8: bl 87390 <explicit_bzero@@GLIBC_2.25+0x50>
0.00 : 662ac: ldr x0, [x20, #8]
0.00 : 662b0: add x19, x0, x19
0.00 : 662b4: str x19, [x20, #8]
0.00 : 662b8: cbnz x28, 66410 <__getdelim@@GLIBC_2.17+0x290>
0.00 : 662bc: mov x0, x20
0.00 : 662c0: bl 73b80 <__underflow@@GLIBC_2.17>
0.00 : 662c4: cmn w0, #0x1
0.00 : 662c8: b.eq 66410 <__getdelim@@GLIBC_2.17+0x290> // b.none
0.00 : 662cc: ldp x27, x19, [x20, #8]
0.00 : 662d0: mov x25, x24
0.00 : 662d4: sub x19, x19, x27
0.00 : 662d8: mov x2, x19
0.00 : 662dc: mov w1, w23
0.00 : 662e0: mov x0, x27
0.00 : 662e4: bl 807b0 <memchr@@GLIBC_2.17>
0.00 : 662e8: cmp x0, #0x0
0.00 : 662ec: mov x28, x0
0.00 : 662f0: sub x0, x0, x27
0.00 : 662f4: csinc x19, x19, x0, eq // eq = none
0.00 : 662f8: mov x0, #0x7fffffffffffffff // #9223372036854775807
0.00 : 662fc: sub x0, x0, x25
0.00 : 66300: cmp x19, x0
0.00 : 66304: b.lt 66260 <__getdelim@@GLIBC_2.17+0xe0> // b.tstop
0.00 : 66308: adrp x0, 17f000 <sys_sigabbrev@@GLIBC_2.17+0x320>
0.00 : 6630c: ldr x0, [x0, #3624]
0.00 : 66310: mrs x2, tpidr_el0
0.00 : 66314: ldr x19, [x29, #16]
0.00 : 66318: mov w3, #0x4b // #75
0.00 : 6631c: ldr w1, [x20]
0.00 : 66320: mov x24, #0xffffffffffffffff // #-1
0.00 : 66324: str w3, [x2, x0]
0.00 : 66328: tbnz w1, #15, 66340 <__getdelim@@GLIBC_2.17+0x1c0>
0.00 : 6632c: ldr x0, [x20, #136]
0.00 : 66330: ldr w1, [x0, #4]
0.00 : 66334: sub w1, w1, #0x1
0.00 : 66338: str w1, [x0, #4]
0.00 : 6633c: cbz w1, 663b8 <__getdelim@@GLIBC_2.17+0x238>
0.00 : 66340: mov x0, x24
0.00 : 66344: ldr x28, [sp, #88]
0.00 : 66348: ldp x20, x21, [x29, #24]
0.00 : 6634c: ldp x22, x23, [x29, #40]
0.00 : 66350: ldp x24, x25, [sp, #56]
0.00 : 66354: ldp x26, x27, [sp, #72]
0.00 : 66358: ldp x29, x30, [sp], #96
0.00 : 6635c: ret
100.00 : 66360: tbz w1, #5, 66218 <__getdelim@@GLIBC_2.17+0x98>
0.00 : 66364: ldp x20, x21, [x29, #24]
0.00 : 66368: mov x24, #0xffffffffffffffff // #-1
0.00 : 6636c: ldp x22, x23, [x29, #40]
0.00 : 66370: mov x0, x24
0.00 : 66374: ldp x24, x25, [sp, #56]
0.00 : 66378: ldp x26, x27, [sp, #72]
0.00 : 6637c: ldr x28, [sp, #88]
0.00 : 66380: ldp x29, x30, [sp], #96
0.00 : 66384: ret
0.00 : 66388: mov x24, #0xffffffffffffffff // #-1
0.00 : 6638c: ldr x19, [x29, #16]
0.00 : 66390: b 66328 <__getdelim@@GLIBC_2.17+0x1a8>
0.00 : 66394: nop
0.00 : 66398: mov x0, x20
0.00 : 6639c: bl 73b80 <__underflow@@GLIBC_2.17>
0.00 : 663a0: cmn w0, #0x1
0.00 : 663a4: b.eq 66438 <__getdelim@@GLIBC_2.17+0x2b8> // b.none
0.00 : 663a8: ldp x27, x19, [x20, #8]
0.00 : 663ac: sub x19, x19, x27
0.00 : 663b0: b 66254 <__getdelim@@GLIBC_2.17+0xd4>
0.00 : 663b4: nop
0.00 : 663b8: str xzr, [x0, #8]
0.00 : 663bc: ldxr w2, [x0]
0.00 : 663c0: stlxr w3, w1, [x0]
0.00 : 663c4: cbnz w3, 663bc <__getdelim@@GLIBC_2.17+0x23c>
0.00 : 663c8: cmp w2, #0x1
0.00 : 663cc: b.le 66340 <__getdelim@@GLIBC_2.17+0x1c0>
0.00 : 663d0: mov x1, #0x81 // #129
0.00 : 663d4: mov x2, #0x1 // #1
0.00 : 663d8: mov x3, #0x0 // #0
0.00 : 663dc: mov x8, #0x62 // #98
0.00 : 663e0: svc #0x0
0.00 : 663e4: ldp x20, x21, [x29, #24]
0.00 : 663e8: ldp x22, x23, [x29, #40]
0.00 : 663ec: b 66370 <__getdelim@@GLIBC_2.17+0x1f0>
0.00 : 663f0: ldr w2, [x0, #4]
0.00 : 663f4: add w2, w2, #0x1
0.00 : 663f8: str w2, [x0, #4]
0.00 : 663fc: tbz w1, #5, 66214 <__getdelim@@GLIBC_2.17+0x94>
0.00 : 66400: mov x24, #0xffffffffffffffff // #-1
0.00 : 66404: ldr x19, [x29, #16]
0.00 : 66408: b 66330 <__getdelim@@GLIBC_2.17+0x1b0>
0.00 : 6640c: nop
0.00 : 66410: ldr x0, [x21]
0.00 : 66414: strb wzr, [x0, x24]
0.00 : 66418: ldr w1, [x20]
0.00 : 6641c: ldr x19, [x29, #16]
0.00 : 66420: b 66328 <__getdelim@@GLIBC_2.17+0x1a8>
0.00 : 66424: nop
0.00 : 66428: mov x24, #0xffffffffffffffff // #-1
0.00 : 6642c: ldr w1, [x20]
0.00 : 66430: b 66328 <__getdelim@@GLIBC_2.17+0x1a8>
0.00 : 66434: nop
0.00 : 66438: mov x24, #0xffffffffffffffff // #-1
0.00 : 6643c: ldr w1, [x20]
0.00 : 66440: ldr x19, [x29, #16]
0.00 : 66444: b 66328 <__getdelim@@GLIBC_2.17+0x1a8>
0.00 : 66448: bl e3ba0 <pthread_setcanceltype@@GLIBC_2.17+0x30>
0.00 : 6644c: b 661f8 <__getdelim@@GLIBC_2.17+0x78>
0.00 : 66450: adrp x0, 17f000 <sys_sigabbrev@@GLIBC_2.17+0x320>
0.00 : 66454: ldr x0, [x0, #3624]
0.00 : 66458: mrs x1, tpidr_el0
0.00 : 6645c: mov w2, #0x16 // #22
0.00 : 66460: mov x24, #0xffffffffffffffff // #-1
0.00 : 66464: str w2, [x1, x0]
0.00 : 66468: b 66370 <__getdelim@@GLIBC_2.17+0x1f0>
0.00 : 6646c: ldr w1, [x20]
0.00 : 66470: mov x4, x0
0.00 : 66474: tbnz w1, #15, 6648c <__getdelim@@GLIBC_2.17+0x30c>
0.00 : 66478: ldr x0, [x20, #136]
0.00 : 6647c: ldr w1, [x0, #4]
0.00 : 66480: sub w1, w1, #0x1
0.00 : 66484: str w1, [x0, #4]
0.00 : 66488: cbz w1, 66494 <__getdelim@@GLIBC_2.17+0x314>
0.00 : 6648c: mov x0, x4
0.00 : 66490: bl 20e40 <gnu_get_libc_version@@GLIBC_2.17+0x130>
0.00 : 66494: str xzr, [x0, #8]
0.00 : 66498: ldxr w2, [x0]
0.00 : 6649c: stlxr w3, w1, [x0]
0.00 : 664a0: cbnz w3, 66498 <__getdelim@@GLIBC_2.17+0x318>
0.00 : 664a4: cmp w2, #0x1
0.00 : 664a8: b.le 6648c <__getdelim@@GLIBC_2.17+0x30c>
0.00 : 664ac: mov x1, #0x81 // #129
0.00 : 664b0: mov x2, #0x1 // #1
0.00 : 664b4: mov x3, #0x0 // #0
0.00 : 664b8: mov x8, #0x62 // #98
0.00 : 664bc: svc #0x0
0.00 : 664c0: b 6648c <__getdelim@@GLIBC_2.17+0x30c>
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Tested-by: Leo Yan <leo.yan@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20210615091704.259202-1-yangjihong1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
pull bot
pushed a commit
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this pull request
Nov 28, 2021
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:8bab4c09f24e("io_uring: allow conditional reschedule for intensive iterators") Signed-off-by: Ye Bin <yebin10@huawei.com> Link: https://lore.kernel.org/r/20211122024737.2198530-1-yebin10@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
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powerpc sets up PF_KTHREAD and PF_IO_WORKER with a NULL pt_regs, which from my (arguably very short) checking is not commonly done for other archs. This is fine, except when PF_IO_WORKER's have been created and the task does something that causes a coredump to be generated. Then we get this crash: Kernel attempted to read user page (160) - exploit attempt? (uid: 1000) BUG: Kernel NULL pointer dereference on read at 0x00000160 Faulting instruction address: 0xc0000000000c3a60 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=32 NUMA pSeries Modules linked in: bochs drm_vram_helper drm_kms_helper xts binfmt_misc ecb ctr syscopyarea sysfillrect cbc sysimgblt drm_ttm_helper aes_generic ttm sg libaes evdev joydev virtio_balloon vmx_crypto gf128mul drm dm_mod fuse loop configfs drm_panel_orientation_quirks ip_tables x_tables autofs4 hid_generic usbhid hid xhci_pci xhci_hcd usbcore usb_common sd_mod CPU: 1 PID: 1982 Comm: ppc-crash Not tainted 6.3.0-rc2+ #88 Hardware name: IBM pSeries (emulated by qemu) POWER9 (raw) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries NIP: c0000000000c3a60 LR: c000000000039944 CTR: c0000000000398e0 REGS: c0000000041833b0 TRAP: 0300 Not tainted (6.3.0-rc2+) MSR: 800000000280b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 88082828 XER: 200400f8 ... NIP memcpy_power7+0x200/0x7d0 LR ppr_get+0x64/0xb0 Call Trace: ppr_get+0x40/0xb0 (unreliable) __regset_get+0x180/0x1f0 regset_get_alloc+0x64/0x90 elf_core_dump+0xb98/0x1b60 do_coredump+0x1c34/0x24a0 get_signal+0x71c/0x1410 do_notify_resume+0x140/0x6f0 interrupt_exit_user_prepare_main+0x29c/0x320 interrupt_exit_user_prepare+0x6c/0xa0 interrupt_return_srr_user+0x8/0x138 Because ppr_get() is trying to copy from a PF_IO_WORKER with a NULL pt_regs. Check for a valid pt_regs in both ppc_get/ppr_set, and return an error if not set. The actual error value doesn't seem to be important here, so just pick -EINVAL. Fixes: fa43981 ("powerpc/ptrace: Enable support for NT_PPPC_TAR, NT_PPC_PPR, NT_PPC_DSCR") Cc: stable@vger.kernel.org # v4.8+ Signed-off-by: Jens Axboe <axboe@kernel.dk> [mpe: Trim oops in change log, add Fixes & Cc stable] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://msgid.link/d9f63344-fe7c-56ae-b420-4a1a04a2ae4c@kernel.dk
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