> This is not caused by a locking bug. The freed structure is a task_struct which is passed by io_sq_thread() to try_to_wake_up(). So the culprit is probably in the io_uring code. cc'ing the io_uring developers for further review. Thanks. This also seems to involve sqpoll.c and io_uring.c. I'm sending an email to both Pavel Begunkov and Jens Axboe, with a cc to io_uring. Thanks, Kun Hu > 2024年12月26日 05:11，Waiman Long <llong@xxxxxxxxxx> 写道： > > On 12/24/24 7:28 AM, Kun Hu wrote: >> Hello, >> >> When using fuzzer tool to fuzz the latest Linux kernel, the following crash >> was triggered. >> >> HEAD commit: 78d4f34e2115b517bcbfe7ec0d018bbbb6f9b0b8 >> git tree: upstream >> Console output:https://drive.google.com/file/d/11IXj9a4uRbOaqIK90F2px6nLiHhJ04rw/view?usp=sharing >> Kernel config: https://drive.google.com/file/d/1RhT5dFTs6Vx1U71PbpenN7TPtnPoa3NI/view?usp=sharing >> C reproducer: https://drive.google.com/file/d/1BP2d5rfb4XBuq0njxKnS6d3AoysIiT61/view?usp=sharing >> Syzlang reproducer: https://drive.google.com/file/d/1lTQrXRQfndtigBiKBxelQeHszr2dzbLp/view?usp=sharing >> Similar report: https://lore.kernel.org/lkml/CALcu4rZOs3sbXBWARhjM6d8UngPUF3bU1CPmSZBugUpgaP_0WA@xxxxxxxxxxxxxx/T/ >> >> >> This bug seems to have been reported and fixed in the old kernel, which seems to be a regression issue? If you fix this issue, please add the following tag to the commit: >> Reported-by: Kun Hu <huk23@xxxxxxxxxxxxxx> >> >> >> ================================================================== >> BUG: KASAN: slab-use-after-free in __lock_acquire+0x370b/0x4a10 kernel/locking/lockdep.c:5089 >> Read of size 8 at addr ff1100000289acb8 by task syz.6.1904/11159 >> >> CPU: 1 UID: 0 PID: 11159 Comm: syz.6.1904 Not tainted 6.13.0-rc3 #3 >> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 >> Call Trace: >> <TASK> >> __dump_stack lib/dump_stack.c:94 [inline] >> dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120 >> print_address_description mm/kasan/report.c:378 [inline] >> print_report+0xcf/0x5f0 mm/kasan/report.c:489 >> kasan_report+0x93/0xc0 mm/kasan/report.c:602 >> __lock_acquire+0x370b/0x4a10 kernel/locking/lockdep.c:5089 >> lock_acquire kernel/locking/lockdep.c:5849 [inline] >> lock_acquire+0x1b1/0x580 kernel/locking/lockdep.c:5814 >> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] >> _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162 >> class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline] >> try_to_wake_up+0xb5/0x23c0 kernel/sched/core.c:4205 >> io_sq_thread_park+0xac/0xe0 io_uring/sqpoll.c:55 >> io_sq_thread_finish+0x6b/0x310 io_uring/sqpoll.c:96 >> io_sq_offload_create+0x162/0x11d0 io_uring/sqpoll.c:497 >> io_uring_create io_uring/io_uring.c:3724 [inline] >> io_uring_setup+0x1728/0x3230 io_uring/io_uring.c:3806 >> __do_sys_io_uring_setup io_uring/io_uring.c:3833 [inline] >> __se_sys_io_uring_setup io_uring/io_uring.c:3827 [inline] >> __x64_sys_io_uring_setup+0x94/0x140 io_uring/io_uring.c:3827 >> do_syscall_x64 arch/x86/entry/common.c:52 [inline] >> do_syscall_64+0xc3/0x1d0 arch/x86/entry/common.c:83 >> entry_SYSCALL_64_after_hwframe+0x77/0x7f >> RIP: 0033:0x7fa4396a071d >> Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48 >> RSP: 002b:00007fa4382f3ba8 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9 >> RAX: ffffffffffffffda RBX: 00007fa439862f80 RCX: 00007fa4396a071d >> RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000002616 >> RBP: 00007fa4382f3c00 R08: 0000000000000000 R09: 0000000000000000 >> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000015 >> R13: 00007fa439862f8c R14: 00007fa439863018 R15: 00007fa4382f3d40 >> </TASK> > > This is not caused by a locking bug. The freed structure is a task_struct which is passed by io_sq_thread() to try_to_wake_up(). So the culprit is probably in the io_uring code. cc'ing the io_uring developers for further review. > > Cheers, > Longman > >> Allocated by task 11159: >> kasan_save_stack+0x24/0x50 mm/kasan/common.c:47 >> kasan_save_track+0x14/0x30 mm/kasan/common.c:68 >> unpoison_slab_object mm/kasan/common.c:319 [inline] >> __kasan_slab_alloc+0x87/0x90 mm/kasan/common.c:345 >> kasan_slab_alloc include/linux/kasan.h:250 [inline] >> slab_post_alloc_hook mm/slub.c:4119 [inline] >> slab_alloc_node mm/slub.c:4168 [inline] >> kmem_cache_alloc_node_noprof+0x14a/0x430 mm/slub.c:4220 >> alloc_task_struct_node kernel/fork.c:180 [inline] >> dup_task_struct kernel/fork.c:1113 [inline] >> copy_process+0x487/0x7500 kernel/fork.c:2225 >> create_io_thread+0xac/0xf0 kernel/fork.c:2755 >> io_sq_offload_create+0xc62/0x11d0 io_uring/sqpoll.c:476 >> io_uring_create io_uring/io_uring.c:3724 [inline] >> io_uring_setup+0x1728/0x3230 io_uring/io_uring.c:3806 >> __do_sys_io_uring_setup io_uring/io_uring.c:3833 [inline] >> __se_sys_io_uring_setup io_uring/io_uring.c:3827 [inline] >> __x64_sys_io_uring_setup+0x94/0x140 io_uring/io_uring.c:3827 >> do_syscall_x64 arch/x86/entry/common.c:52 [inline] >> do_syscall_64+0xc3/0x1d0 arch/x86/entry/common.c:83 >> entry_SYSCALL_64_after_hwframe+0x77/0x7f >> >> Freed by task 24: >> kasan_save_stack+0x24/0x50 mm/kasan/common.c:47 >> kasan_save_track+0x14/0x30 mm/kasan/common.c:68 >> kasan_save_free_info+0x3a/0x60 mm/kasan/generic.c:582 >> poison_slab_object mm/kasan/common.c:247 [inline] >> __kasan_slab_free+0x54/0x70 mm/kasan/common.c:264 >> kasan_slab_free include/linux/kasan.h:233 [inline] >> slab_free_hook mm/slub.c:2353 [inline] >> slab_free mm/slub.c:4613 [inline] >> kmem_cache_free+0x126/0x4d0 mm/slub.c:4715 >> put_task_struct include/linux/sched/task.h:144 [inline] >> put_task_struct include/linux/sched/task.h:131 [inline] >> delayed_put_task_struct+0x229/0x300 kernel/exit.c:227 >> rcu_do_batch kernel/rcu/tree.c:2567 [inline] >> rcu_core+0x7cb/0x16c0 kernel/rcu/tree.c:2823 >> handle_softirqs+0x1ad/0x870 kernel/softirq.c:561 >> run_ksoftirqd kernel/softirq.c:950 [inline] >> run_ksoftirqd+0x3a/0x60 kernel/softirq.c:942 >> smpboot_thread_fn+0x669/0xa80 kernel/smpboot.c:164 >> kthread+0x345/0x450 kernel/kthread.c:389 >> ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147 >> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 >> >> Last potentially related work creation: >> kasan_save_stack+0x24/0x50 mm/kasan/common.c:47 >> __kasan_record_aux_stack+0xa6/0xc0 mm/kasan/generic.c:544 >> __call_rcu_common.constprop.0+0x99/0x790 kernel/rcu/tree.c:3086 >> put_task_struct_rcu_user+0x75/0xc0 kernel/exit.c:233 >> finish_task_switch+0x4d2/0x720 kernel/sched/core.c:5278 >> context_switch kernel/sched/core.c:5372 [inline] >> __schedule+0xe68/0x4120 kernel/sched/core.c:6756 >> __schedule_loop kernel/sched/core.c:6833 [inline] >> schedule+0xd4/0x210 kernel/sched/core.c:6848 >> do_nanosleep+0x20e/0x4e0 kernel/time/hrtimer.c:2079 >> hrtimer_nanosleep+0x122/0x330 kernel/time/hrtimer.c:2126 >> common_nsleep+0xaa/0xd0 kernel/time/posix-timers.c:1356 >> __do_sys_clock_nanosleep kernel/time/posix-timers.c:1402 [inline] >> __se_sys_clock_nanosleep kernel/time/posix-timers.c:1379 [inline] >> __x64_sys_clock_nanosleep+0x33c/0x490 kernel/time/posix-timers.c:1379 >> do_syscall_x64 arch/x86/entry/common.c:52 [inline] >> do_syscall_64+0xc3/0x1d0 arch/x86/entry/common.c:83 >> entry_SYSCALL_64_after_hwframe+0x77/0x7f >> >> The buggy address belongs to the object at ff1100000289a340 >> which belongs to the cache task_struct of size 8712 >> The buggy address is located 2424 bytes inside of >> freed 8712-byte region [ff1100000289a340, ff1100000289c548) >> >> The buggy address belongs to the physical page: >> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2898 >> head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0 >> flags: 0x100000000000040(head|node=0|zone=1) >> page_type: f5(slab) >> raw: 0100000000000040 ff110000014cb040 ffd4000000549800 dead000000000004 >> raw: 0000000000000000 0000000080030003 00000001f5000000 0000000000000000 >> head: 0100000000000040 ff110000014cb040 ffd4000000549800 dead000000000004 >> head: 0000000000000000 0000000080030003 00000001f5000000 0000000000000000 >> head: 0100000000000003 ffd40000000a2601 ffffffffffffffff 0000000000000000 >> head: ff11000000000008 0000000000000000 00000000ffffffff 0000000000000000 >> page dumped because: kasan: bad access detected >> >> Memory state around the buggy address: >> ff1100000289ab80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ff1100000289ac00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >>> ff1100000289ac80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ^ >> ff1100000289ad00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ff1100000289ad80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ================================================================== >> >> >> —————— >> Thanks, >> Kun Hu >> > >
