Hello, syzbot found the following issue on: HEAD commit: 40354149f4d7 Add linux-next specific files for 20220414 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=16ae0bd0f00000 kernel config: https://syzkaller.appspot.com/x/.config?x=a44d62051576f6f5 dashboard link: https://syzkaller.appspot.com/bug?extid=306090cfa3294f0bbfb3 compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=164417ccf00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=104d63d0f00000 The issue was bisected to: commit e257039f0fc7da36ac3a522ef9a5cb4ae7852e67 Author: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Date: Tue Mar 1 04:04:20 2022 +0000 mount_setattr(): clean the control flow and calling conventions bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14622210f00000 final oops: https://syzkaller.appspot.com/x/report.txt?x=16622210f00000 console output: https://syzkaller.appspot.com/x/log.txt?x=12622210f00000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+306090cfa3294f0bbfb3@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: e257039f0fc7 ("mount_setattr(): clean the control flow and calling conventions") rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (10499 ticks this GP) idle=23b/1/0x4000000000000000 softirq=5447/5447 fqs=5210 (t=10500 jiffies g=4401 q=63 ncpus=2) NMI backtrace for cpu 1 CPU: 1 PID: 3614 Comm: syz-executor153 Not tainted 5.18.0-rc2-next-20220414-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: <IRQ> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1e6/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x262/0x3f0 kernel/rcu/tree_stall.h:369 print_cpu_stall kernel/rcu/tree_stall.h:665 [inline] check_cpu_stall kernel/rcu/tree_stall.h:749 [inline] rcu_pending kernel/rcu/tree.c:4010 [inline] rcu_sched_clock_irq.cold+0x144/0x8fc kernel/rcu/tree.c:2675 update_process_times+0x16d/0x200 kernel/time/timer.c:1811 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:243 tick_sched_timer+0xee/0x120 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:__mnt_want_write+0xdd/0x2e0 fs/namespace.c:348 Code: 00 02 00 00 89 de e8 22 64 9c ff 85 db 74 42 48 b8 00 00 00 00 00 fc ff df 4d 89 ec 49 c1 ec 03 49 01 c4 e8 e5 61 9c ff f3 90 <41> 0f b6 04 24 84 c0 74 08 3c 03 0f 8e 99 01 00 00 8b 5d 10 31 ff RSP: 0018:ffffc90003acfdf0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000200 RCX: 0000000000000000 RDX: ffff8880209957c0 RSI: ffffffff81dda00b RDI: 0000000000000003 RBP: ffff888140174c20 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff81dda030 R11: 1ffffffff1f09899 R12: ffffed102802e986 R13: ffff888140174c30 R14: ffff888140174c50 R15: 0000000000000000 mnt_want_write+0x13d/0x3e0 fs/namespace.c:394 path_setxattr+0xb2/0x1c0 fs/xattr.c:627 __do_sys_lsetxattr fs/xattr.c:652 [inline] __se_sys_lsetxattr fs/xattr.c:648 [inline] __x64_sys_lsetxattr+0xbd/0x150 fs/xattr.c:648 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f7262608cc9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 11 15 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f72625992f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd RAX: ffffffffffffffda RBX: 00007f72626904b0 RCX: 00007f7262608cc9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000600 RBP: 00007f726265e074 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e R13: 695f70756f72672c R14: 695f726573752c30 R15: 00007f72626904b8 </TASK> ---------------- Code disassembly (best guess): 0: 00 02 add %al,(%rdx) 2: 00 00 add %al,(%rax) 4: 89 de mov %ebx,%esi 6: e8 22 64 9c ff callq 0xff9c642d b: 85 db test %ebx,%ebx d: 74 42 je 0x51 f: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 16: fc ff df 19: 4d 89 ec mov %r13,%r12 1c: 49 c1 ec 03 shr $0x3,%r12 20: 49 01 c4 add %rax,%r12 23: e8 e5 61 9c ff callq 0xff9c620d 28: f3 90 pause * 2a: 41 0f b6 04 24 movzbl (%r12),%eax <-- trapping instruction 2f: 84 c0 test %al,%al 31: 74 08 je 0x3b 33: 3c 03 cmp $0x3,%al 35: 0f 8e 99 01 00 00 jle 0x1d4 3b: 8b 5d 10 mov 0x10(%rbp),%ebx 3e: 31 ff xor %edi,%edi --- 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
