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SubjectRe: [syzbot] inconsistent lock state in sync_info_debugfs_show
From
Am 22.11.22 um 15:51 schrieb Daniel Vetter:
> On Fri, Nov 18, 2022 at 06:46:38PM -0800, syzbot wrote:
>> syzbot has found a reproducer for the following issue on:
>>
>> HEAD commit: 84368d882b96 Merge tag 'soc-fixes-6.1-3' of git://git.kern..
>> git tree: upstream
>> console+strace: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsyzkaller.appspot.com%2Fx%2Flog.txt%3Fx%3D1670fb65880000&data=05%7C01%7Cchristian.koenig%40amd.com%7C93106507f7994c3175f408dacc99034c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638047254866307874%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=%2BNj%2B3vZRTi6DhdOdNlQDG7GJN9u3IZy8%2FZxqHScu2Fs%3D&reserved=0
>> kernel config: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsyzkaller.appspot.com%2Fx%2F.config%3Fx%3D6f4e5e9899396248&data=05%7C01%7Cchristian.koenig%40amd.com%7C93106507f7994c3175f408dacc99034c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638047254866307874%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=qZpvAr44nbuFs3jvd9fggeVnMgAt7J5Izxa1GvoMDjA%3D&reserved=0
>> dashboard link: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsyzkaller.appspot.com%2Fbug%3Fextid%3D007bfe0f3330f6e1e7d1&data=05%7C01%7Cchristian.koenig%40amd.com%7C93106507f7994c3175f408dacc99034c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638047254866307874%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=tTHNWwrjD%2F%2FddfRi%2Fe3AbwMw%2B7MPWoolWeZt%2FgnBa4g%3D&reserved=0
>> compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
>> syz repro: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsyzkaller.appspot.com%2Fx%2Frepro.syz%3Fx%3D164376f9880000&data=05%7C01%7Cchristian.koenig%40amd.com%7C93106507f7994c3175f408dacc99034c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638047254866307874%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=bay5gePJjT3Nm4J%2BINtso1hKNPMUmfP6xActclfXqa8%3D&reserved=0
>> C reproducer: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsyzkaller.appspot.com%2Fx%2Frepro.c%3Fx%3D16cf0965880000&data=05%7C01%7Cchristian.koenig%40amd.com%7C93106507f7994c3175f408dacc99034c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638047254866307874%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=o5JlI1IDcmP%2Bd08wLRhyD5gUIjuPioMEyK%2FkH6m%2FNIQ%3D&reserved=0
>>
>> Downloadable assets:
>> disk image: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstorage.googleapis.com%2Fsyzbot-assets%2F031b6e68785d%2Fdisk-84368d88.raw.xz&data=05%7C01%7Cchristian.koenig%40amd.com%7C93106507f7994c3175f408dacc99034c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638047254866307874%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=dAT5hGTqrR01QiyGbOHyWkBIvTYvsmGqLiPqXuw7vK4%3D&reserved=0
>> vmlinux: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstorage.googleapis.com%2Fsyzbot-assets%2Fcff5e66b90e8%2Fvmlinux-84368d88.xz&data=05%7C01%7Cchristian.koenig%40amd.com%7C93106507f7994c3175f408dacc99034c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638047254866307874%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=bHMhF3kWMS3ZVbPs8z6mWewUlNBTJPabhhI58e77KuI%3D&reserved=0
>> kernel image: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fstorage.googleapis.com%2Fsyzbot-assets%2Fe75525784a66%2FbzImage-84368d88.xz&data=05%7C01%7Cchristian.koenig%40amd.com%7C93106507f7994c3175f408dacc99034c%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C638047254866307874%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=KFJD3fDW1Ppqla%2BPA6wY6NC3qSNrlCpnkhdqIDZGxoY%3D&reserved=0
>>
>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>> Reported-by: syzbot+007bfe0f3330f6e1e7d1@syzkaller.appspotmail.com
>>
>> ================================
>> WARNING: inconsistent lock state
>> 6.1.0-rc5-syzkaller-00144-g84368d882b96 #0 Not tainted
>> --------------------------------
>> inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
>> syz-executor333/3645 [HC0[0]:SC0[0]:HE0:SE1] takes:
>> ffffffff8d295c38 (sync_timeline_list_lock){?...}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:375 [inline]
>> ffffffff8d295c38 (sync_timeline_list_lock){?...}-{2:2}, at: sync_info_debugfs_show+0x31/0x200 drivers/dma-buf/sync_debug.c:147
>> {IN-HARDIRQ-W} state was registered at:
>> lock_acquire kernel/locking/lockdep.c:5668 [inline]
>> lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633
>> __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
>> _raw_spin_lock_irqsave+0x3d/0x60 kernel/locking/spinlock.c:162
>> sync_timeline_debug_remove+0x29/0x1a0 drivers/dma-buf/sync_debug.c:31
>> sync_timeline_free drivers/dma-buf/sw_sync.c:104 [inline]
>> kref_put include/linux/kref.h:65 [inline]
>> sync_timeline_put drivers/dma-buf/sw_sync.c:116 [inline]
>> timeline_fence_release+0x267/0x340 drivers/dma-buf/sw_sync.c:144
>> dma_fence_release+0x14b/0x690 drivers/dma-buf/dma-fence.c:559
> Do we need to just generally push all dma_fence_release finalization to an
> irq work to untangle this mess once and for all? Or is this not just plain
> old recursion? Christian, any good ideas?

I couldn't even figure out what exactly is going wrong here.

As far as I can see someone just constructed a timeline_fence within a
timeline_fence which doesn't sounds valid to me in the first place.

Christian.

> -Daniel
>
>> kref_put include/linux/kref.h:65 [inline]
>> dma_fence_put include/linux/dma-fence.h:276 [inline]
>> dma_fence_array_release+0x1fa/0x2d0 drivers/dma-buf/dma-fence-array.c:120
>> dma_fence_release+0x14b/0x690 drivers/dma-buf/dma-fence.c:559
>> kref_put include/linux/kref.h:65 [inline]
>> dma_fence_put include/linux/dma-fence.h:276 [inline]
>> irq_dma_fence_array_work+0xa9/0xd0 drivers/dma-buf/dma-fence-array.c:52
>> irq_work_single+0x124/0x260 kernel/irq_work.c:211
>> irq_work_run_list kernel/irq_work.c:242 [inline]
>> irq_work_run_list+0x91/0xc0 kernel/irq_work.c:225
>> irq_work_run+0x58/0xd0 kernel/irq_work.c:251
>> __sysvec_irq_work+0xce/0x4e0 arch/x86/kernel/irq_work.c:22
>> sysvec_irq_work+0x92/0xc0 arch/x86/kernel/irq_work.c:17
>> asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:675
>> __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
>> _raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:202
>> spin_unlock_irq include/linux/spinlock.h:400 [inline]
>> sw_sync_debugfs_release+0x162/0x240 drivers/dma-buf/sw_sync.c:321
>> __fput+0x27c/0xa90 fs/file_table.c:320
>> task_work_run+0x16f/0x270 kernel/task_work.c:179
>> ptrace_notify+0x118/0x140 kernel/signal.c:2354
>> ptrace_report_syscall include/linux/ptrace.h:420 [inline]
>> ptrace_report_syscall_exit include/linux/ptrace.h:482 [inline]
>> syscall_exit_work kernel/entry/common.c:251 [inline]
>> syscall_exit_to_user_mode_prepare+0x129/0x280 kernel/entry/common.c:278
>> __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
>> syscall_exit_to_user_mode+0xd/0x50 kernel/entry/common.c:296
>> do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86
>> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>> irq event stamp: 638
>> hardirqs last enabled at (637): [<ffffffff81cc6530>] ___slab_alloc+0xca0/0x1400 mm/slub.c:3132
>> hardirqs last disabled at (638): [<ffffffff89f47e95>] __raw_spin_lock_irq include/linux/spinlock_api_smp.h:117 [inline]
>> hardirqs last disabled at (638): [<ffffffff89f47e95>] _raw_spin_lock_irq+0x45/0x50 kernel/locking/spinlock.c:170
>> softirqs last enabled at (538): [<ffffffff814c1d03>] invoke_softirq kernel/softirq.c:445 [inline]
>> softirqs last enabled at (538): [<ffffffff814c1d03>] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650
>> softirqs last disabled at (505): [<ffffffff814c1d03>] invoke_softirq kernel/softirq.c:445 [inline]
>> softirqs last disabled at (505): [<ffffffff814c1d03>] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650
>>
>> other info that might help us debug this:
>> Possible unsafe locking scenario:
>>
>> CPU0
>> ----
>> lock(sync_timeline_list_lock);
>> <Interrupt>
>> lock(sync_timeline_list_lock);
>>
>> *** DEADLOCK ***
>>
>> 2 locks held by syz-executor333/3645:
>> #0: ffff888021f8c8b8 (&p->lock){+.+.}-{3:3}, at: seq_read_iter+0xe3/0x1280 fs/seq_file.c:182
>> #1: ffffffff8d295c38 (sync_timeline_list_lock){?...}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:375 [inline]
>> #1: ffffffff8d295c38 (sync_timeline_list_lock){?...}-{2:2}, at: sync_info_debugfs_show+0x31/0x200 drivers/dma-buf/sync_debug.c:147
>>
>> stack backtrace:
>> CPU: 1 PID: 3645 Comm: syz-executor333 Not tainted 6.1.0-rc5-syzkaller-00144-g84368d882b96 #0
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
>> Call Trace:
>> <TASK>
>> __dump_stack lib/dump_stack.c:88 [inline]
>> dump_stack_lvl+0xd1/0x138 lib/dump_stack.c:106
>> print_usage_bug kernel/locking/lockdep.c:3963 [inline]
>> valid_state kernel/locking/lockdep.c:3975 [inline]
>> mark_lock_irq kernel/locking/lockdep.c:4178 [inline]
>> mark_lock.part.0.cold+0x18/0xd8 kernel/locking/lockdep.c:4634
>> mark_lock kernel/locking/lockdep.c:4598 [inline]
>> mark_held_locks+0x9f/0xe0 kernel/locking/lockdep.c:4236
>> __trace_hardirqs_on_caller kernel/locking/lockdep.c:4254 [inline]
>> lockdep_hardirqs_on_prepare kernel/locking/lockdep.c:4321 [inline]
>> lockdep_hardirqs_on_prepare+0x139/0x410 kernel/locking/lockdep.c:4273
>> trace_hardirqs_on+0x31/0x160 kernel/trace/trace_preemptirq.c:49
>> __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
>> _raw_spin_unlock_irq+0x23/0x50 kernel/locking/spinlock.c:202
>> spin_unlock_irq include/linux/spinlock.h:400 [inline]
>> sync_print_obj drivers/dma-buf/sync_debug.c:118 [inline]
>> sync_info_debugfs_show+0xef/0x200 drivers/dma-buf/sync_debug.c:153
>> seq_read_iter+0x4f9/0x1280 fs/seq_file.c:230
>> seq_read+0x171/0x210 fs/seq_file.c:162
>> vfs_read+0x25b/0x930 fs/read_write.c:468
>> ksys_read+0x12b/0x250 fs/read_write.c:613
>> do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>> do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
>> entry_SYSCALL_64_after_hwframe+0x63/0xcd
>> RIP: 0033:0x7f7cb1bbb049
>> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 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 c0 ff ff ff f7 d8 64 89 01 48
>> RSP: 002b:00007ffd52951818 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
>> RAX: ffffffffffffffda RBX: 00000000000f4240 RCX: 00007f7cb1bbb049
>> RDX: 0000000000002020 RSI: 0000000020002200 RDI: 0000000000000003
>> RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001
>> R10: 00007ffd52951290 R11: 0000000000000246 R12: 000000000000e32c
>> R13: 00007ffd5295182c R14: 00007ffd52951840 R15: 00007ffd52951830
>> </TASK>
>>

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