On 09/01/2021 16:27, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 36bbbd0e Merge branch 'rcu/urgent' of git://git.kernel.org.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=149afeeb500000 > kernel config: https://syzkaller.appspot.com/x/.config?x=8aa30b9da402d224 > dashboard link: https://syzkaller.appspot.com/bug?extid=99ed55100402022a6276 > compiler: gcc (GCC) 10.1.0-syz 20200507 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10496f70d00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10cedf70d00000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+99ed55100402022a6276@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 4d004099a668 ("lockdep: Fix lockdep recursion") Looks like the fixed ERR_PTR vs NULL issue. #syz test: git://git.kernel.dk/linux-block d9d05217cb6990b9a56e13b56e7a1b71e2551f6c > > RBP: 0000000000000005 R08: 0000000000000001 R09: 0000000000401140 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402860 > R13: 00000000004028f0 R14: 0000000000000000 R15: 0000000000000000 > BUG: unable to handle page fault for address: fffffffffffffffc > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD b08f067 P4D b08f067 PUD b091067 PMD 0 > Oops: 0000 [#1] PREEMPT SMP KASAN > CPU: 0 PID: 8500 Comm: syz-executor191 Not tainted 5.11.0-rc2-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:percpu_ref_exit+0x2f/0x140 lib/percpu-refcount.c:130 > Code: 54 55 53 48 89 fb e8 f0 fc b6 fd 48 8d 6b 08 48 b8 00 00 00 00 00 fc ff df 48 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 d5 00 00 00 <4c> 8b 73 08 48 89 df e8 c5 fe ff ff 4d 85 f6 0f 84 b3 00 00 00 e8 > RSP: 0018:ffffc9000126fcc8 EFLAGS: 00010246 > RAX: dffffc0000000000 RBX: fffffffffffffff4 RCX: 0000000000000000 > RDX: 1fffffffffffffff RSI: ffffffff83bb78b0 RDI: fffffffffffffff4 > RBP: fffffffffffffffc R08: 0000000000000001 R09: ffffffff8ebda867 > R10: fffffbfff1d7b50c R11: 0000000000000000 R12: 0000000000000000 > R13: ffff88801adee000 R14: 0000000000000002 R15: fffffffffffffff4 > FS: 000000000179f940(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: fffffffffffffffc CR3: 0000000020270000 CR4: 00000000001506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > destroy_fixed_file_ref_node fs/io_uring.c:7703 [inline] > io_sqe_files_unregister+0x30b/0x770 fs/io_uring.c:7293 > __io_uring_register fs/io_uring.c:9916 [inline] > __do_sys_io_uring_register+0x1185/0x4080 fs/io_uring.c:10000 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x444df9 > Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 0f 83 db d5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007ffeb192ade8 EFLAGS: 00000246 ORIG_RAX: 00000000000001ab > RAX: ffffffffffffffda RBX: 00007ffeb192ae90 RCX: 0000000000444df9 > RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000004 > RBP: 0000000000000005 R08: 0000000000000001 R09: 0000000000401140 > R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000402860 > R13: 00000000004028f0 R14: 0000000000000000 R15: 0000000000000000 > Modules linked in: > CR2: fffffffffffffffc > ---[ end trace ed34d5d65a155c02 ]--- > RIP: 0010:percpu_ref_exit+0x2f/0x140 lib/percpu-refcount.c:130 > Code: 54 55 53 48 89 fb e8 f0 fc b6 fd 48 8d 6b 08 48 b8 00 00 00 00 00 fc ff df 48 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 d5 00 00 00 <4c> 8b 73 08 48 89 df e8 c5 fe ff ff 4d 85 f6 0f 84 b3 00 00 00 e8 > RSP: 0018:ffffc9000126fcc8 EFLAGS: 00010246 > RAX: dffffc0000000000 RBX: fffffffffffffff4 RCX: 0000000000000000 > RDX: 1fffffffffffffff RSI: ffffffff83bb78b0 RDI: fffffffffffffff4 > RBP: fffffffffffffffc R08: 0000000000000001 R09: ffffffff8ebda867 > R10: fffffbfff1d7b50c R11: 0000000000000000 R12: 0000000000000000 > R13: ffff88801adee000 R14: 0000000000000002 R15: fffffffffffffff4 > FS: 000000000179f940(0000) GS:ffff8880b9e00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: fffffffffffffffc CR3: 0000000020270000 CR4: 00000000001506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > syzbot can test patches for this issue, for details see: > https://goo.gl/tpsmEJ#testing-patches > -- Pavel Begunkov
