* Re: [PATCH v4 5/5] io_uring: avoid uring_lock for IORING_SETUP_SINGLE_ISSUER
2025-12-10 6:20 ` [PATCH v4 5/5] io_uring: avoid uring_lock for IORING_SETUP_SINGLE_ISSUER kernel test robot
@ 2025-12-15 17:27 ` Caleb Sander Mateos
0 siblings, 0 replies; 2+ messages in thread
From: Caleb Sander Mateos @ 2025-12-15 17:27 UTC (permalink / raw)
To: kernel test robot; +Cc: oe-lkp, lkp, io-uring, Jens Axboe, linux-kernel, syzbot
On Tue, Dec 9, 2025 at 10:20 PM kernel test robot <oliver.sang@intel.com> wrote:
>
>
>
> Hello,
>
> kernel test robot noticed "Oops:general_protection_fault,probably_for_non-canonical_address#:#[##]KASAN" on:
>
> commit: a924e7ffd1b0b2e015ed1174662d52053a2339c4 ("[PATCH v4 5/5] io_uring: avoid uring_lock for IORING_SETUP_SINGLE_ISSUER")
> url: https://github.com/intel-lab-lkp/linux/commits/Caleb-Sander-Mateos/io_uring-use-release-acquire-ordering-for-IORING_SETUP_R_DISABLED/20251203-004502
> base: https://git.kernel.org/cgit/linux/kernel/git/axboe/linux.git for-next
> patch link: https://lore.kernel.org/all/20251202164121.3612929-6-csander@purestorage.com/
> patch subject: [PATCH v4 5/5] io_uring: avoid uring_lock for IORING_SETUP_SINGLE_ISSUER
>
> in testcase: trinity
> version:
> with following parameters:
>
> runtime: 300s
> group: group-00
> nr_groups: 5
>
>
>
> config: x86_64-randconfig-015-20251205
> compiler: gcc-14
> test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 32G
>
> (please refer to attached dmesg/kmsg for entire log/backtrace)
>
>
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <oliver.sang@intel.com>
> | Closes: https://lore.kernel.org/oe-lkp/202512101405.a7a2bdb2-lkp@intel.com
>
>
> [ 617.261968][ T3783] Oops: general protection fault, probably for non-canonical address 0xdffffc00000000f3: 0000 [#1] KASAN
> [ 617.267361][ T3783] KASAN: null-ptr-deref in range [0x0000000000000798-0x000000000000079f]
> [ 617.268334][ T3783] CPU: 0 UID: 65534 PID: 3783 Comm: trinity-c0 Not tainted 6.18.0-rc6-00312-ga924e7ffd1b0 #1 PREEMPT(lazy) f22e3d733e0666690a06b271bf82578b56b40aa3
> [ 617.269927][ T3783] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> [ 617.271108][ T3783] RIP: 0010:task_work_add (kbuild/src/consumer/kernel/task_work.c:68 (discriminator 2))
> [ 617.271772][ T3783] Code: 39 25 df fe 67 03 0f 85 8c 01 00 00 e8 1c bd 24 00 4d 8d ac 24 98 07 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 2f 02 00 00 49 89 df 48 8d 44 24 38 4d 8b b4 24
> All code
> ========
> 0: 39 25 df fe 67 03 cmp %esp,0x367fedf(%rip) # 0x367fee5
> 6: 0f 85 8c 01 00 00 jne 0x198
> c: e8 1c bd 24 00 call 0x24bd2d
> 11: 4d 8d ac 24 98 07 00 lea 0x798(%r12),%r13
> 18: 00
> 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
> 20: fc ff df
> 23: 4c 89 ea mov %r13,%rdx
> 26: 48 c1 ea 03 shr $0x3,%rdx
> 2a:* 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
> 2e: 0f 85 2f 02 00 00 jne 0x263
> 34: 49 89 df mov %rbx,%r15
> 37: 48 8d 44 24 38 lea 0x38(%rsp),%rax
> 3c: 4d rex.WRB
> 3d: 8b .byte 0x8b
> 3e: b4 24 mov $0x24,%ah
>
> Code starting with the faulting instruction
> ===========================================
> 0: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
> 4: 0f 85 2f 02 00 00 jne 0x239
> a: 49 89 df mov %rbx,%r15
> d: 48 8d 44 24 38 lea 0x38(%rsp),%rax
> 12: 4d rex.WRB
> 13: 8b .byte 0x8b
> 14: b4 24 mov $0x24,%ah
> [ 617.273774][ T3783] RSP: 0018:ffff88816ac9fb10 EFLAGS: 00010206
> [ 617.274486][ T3783] RAX: dffffc0000000000 RBX: ffff88816ac9fbe0 RCX: 0000000000000000
> [ 617.275413][ T3783] RDX: 00000000000000f3 RSI: 0000000000000000 RDI: 0000000000000000
> [ 617.276336][ T3783] RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
> [ 617.277257][ T3783] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
> [ 617.278178][ T3783] R13: 0000000000000798 R14: 1ffff1102d593f65 R15: ffff88816ac9fcf0
> [ 617.279075][ T3783] FS: 00000000010a2880(0000) GS:0000000000000000(0000) knlGS:0000000000000000
> [ 617.280114][ T3783] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 617.280856][ T3783] CR2: 00000000d684d000 CR3: 000000015f35b000 CR4: 00000000000406f0
> [ 617.281749][ T3783] Call Trace:
> [ 617.282202][ T3783] <TASK>
> [ 617.282613][ T3783] ? lockdep_init_map_type (kbuild/src/consumer/kernel/locking/lockdep.c:4973 (discriminator 1))
> [ 617.283274][ T3783] ? task_work_set_notify_irq (kbuild/src/consumer/kernel/task_work.c:56)
> [ 617.283904][ T3783] ? lockdep_init_map_type (kbuild/src/consumer/kernel/locking/lockdep.c:4973 (discriminator 1))
> [ 617.284515][ T3783] ? __init_swait_queue_head (kbuild/src/consumer/include/linux/list.h:45 (discriminator 2) kbuild/src/consumer/kernel/sched/swait.c:12 (discriminator 2))
>
>
> The kernel config and materials to reproduce are available at:
> https://download.01.org/0day-ci/archive/20251210/202512101405.a7a2bdb2-lkp@intel.com
The full Call Trace is more useful:
[ 617.261968][ T3783] Oops: general protection fault, probably for
non-canonical address 0xdffffc00000000f3: 0000 [#1] KASAN
[ 617.267361][ T3783] KASAN: null-ptr-deref in range
[0x0000000000000798-0x000000000000079f]
[ 617.268334][ T3783] CPU: 0 UID: 65534 PID: 3783 Comm: trinity-c0
Not tainted 6.18.0-rc6-00312-ga924e7ffd1b0 #1 PREEMPT(lazy)
f22e3d733e0666690a06b271bf82578b56b40aa3
[ 617.269927][ T3783] Hardware name: QEMU Standard PC (i440FX + PIIX,
1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 617.271108][ T3783] RIP: 0010:task_work_add+0xbd/0x330
[ 617.271772][ T3783] Code: 39 25 df fe 67 03 0f 85 8c 01 00 00 e8 1c
bd 24 00 4d 8d ac 24 98 07 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89
ea 48 c1 ea 03 <80> 3c 02 00 0f 85 2f 02 00 00 49 89 df 48 8d 44 24 38
4d 8b b4 24
[ 617.273774][ T3783] RSP: 0018:ffff88816ac9fb10 EFLAGS: 00010206
[ 617.274486][ T3783] RAX: dffffc0000000000 RBX: ffff88816ac9fbe0
RCX: 0000000000000000
[ 617.275413][ T3783] RDX: 00000000000000f3 RSI: 0000000000000000
RDI: 0000000000000000
[ 617.276336][ T3783] RBP: 0000000000000002 R08: 0000000000000000
R09: 0000000000000000
[ 617.277257][ T3783] R10: 0000000000000000 R11: 0000000000000000
R12: 0000000000000000
[ 617.278178][ T3783] R13: 0000000000000798 R14: 1ffff1102d593f65
R15: ffff88816ac9fcf0
[ 617.279075][ T3783] FS: 00000000010a2880(0000)
GS:0000000000000000(0000) knlGS:0000000000000000
[ 617.280114][ T3783] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 617.280856][ T3783] CR2: 00000000d684d000 CR3: 000000015f35b000
CR4: 00000000000406f0
[ 617.281749][ T3783] Call Trace:
[ 617.282202][ T3783] <TASK>
[ 617.282613][ T3783] ? lockdep_init_map_type+0x5c/0x240
[ 617.283274][ T3783] ? task_work_set_notify_irq+0x60/0x60
[ 617.283904][ T3783] ? lockdep_init_map_type+0x5c/0x240
[ 617.284515][ T3783] ? __init_swait_queue_head+0xca/0x160
[ 617.285149][ T3783] io_ring_ctx_lock_nested+0x295/0x340
[ 617.285859][ T3783] ? io_cqring_timer_wakeup+0xb0/0xb0
[ 617.286469][ T3783] ? perf_trace_io_uring_submit_req+0x20/0x20
[ 617.287193][ T3783] ? nohz_balancer_kick+0x140/0x7a0
[ 617.294458][ T3783] ? io_rings_free+0x7b/0xe0
[ 617.295099][ T3783] io_ring_ctx_wait_and_kill+0x6e/0x220
[ 617.295749][ T3783] ? percpu_counter_add+0x90/0x90
[ 617.296356][ T3783] ? security_capset+0xa0/0xc0
[ 617.296941][ T3783] io_uring_create+0xa0f/0xa52
[ 617.297537][ T3783] ? io_uring_poll.cold+0x1a/0x1a
[ 617.298159][ T3783] io_uring_setup.cold+0x1a/0x2e
[ 617.298772][ T3783] ? io_prepare_config+0xb10/0xb10
[ 617.299469][ T3783] __x64_sys_io_uring_setup+0xc4/0x170
[ 617.300135][ T3783] do_syscall_64+0x72/0xe40
[ 617.300725][ T3783] entry_SYSCALL_64_after_hwframe+0x4b/0x53
So we're calling io_ring_ctx_wait_and_kill() from io_uring_create(),
meaning the io_uring creation errored out early. Looks like there are
several "goto err;" paths before ctx->submitter_task is assigned. If
those error paths are taken, io_ring_ctx_lock_nested() can be called
in the IORING_SETUP_SINGLE_ISSUER && !IORING_SETUP_R_DISABLED case
with a NULL submitter_task. I think this can be fixed by just
initializing submitter_task earlier.
Thanks,
Caleb
>
>
>
> --
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
>
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