Hello, syzbot found the following issue on: HEAD commit: b2d229d4ddb1 Linux 5.18-rc3 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=144417ccf00000 kernel config: https://syzkaller.appspot.com/x/.config?x=6cb89c879305f336 dashboard link: https://syzkaller.appspot.com/bug?extid=10a16d1c43580983f6a2 compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=104a88e8f00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=132a840cf00000 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=16b313c0f00000 final oops: https://syzkaller.appspot.com/x/report.txt?x=15b313c0f00000 console output: https://syzkaller.appspot.com/x/log.txt?x=11b313c0f00000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+10a16d1c43580983f6a2@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: e257039f0fc7 ("mount_setattr(): clean the control flow and calling conventions") rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-....: (10500 ticks this GP) idle=bb3/1/0x4000000000000000 softirq=5340/5340 fqs=5250 (t=10502 jiffies g=4461 q=33) NMI backtrace for cpu 1 CPU: 1 PID: 3616 Comm: syz-executor364 Not tainted 5.18.0-rc3-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+0x1e3/0x2cb lib/dump_stack.c:106 nmi_cpu_backtrace+0x473/0x4a0 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x168/0x280 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x236/0x3a0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:639 [inline] check_cpu_stall kernel/rcu/tree_stall.h:723 [inline] rcu_pending kernel/rcu/tree.c:3923 [inline] rcu_sched_clock_irq+0xf1b/0x18d0 kernel/rcu/tree.c:2625 update_process_times+0x197/0x200 kernel/time/timer.c:1788 tick_sched_handle kernel/time/tick-sched.c:243 [inline] tick_sched_timer+0x377/0x540 kernel/time/tick-sched.c:1473 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x3a6/0xfd0 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0xf9/0x280 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1097 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0010:__mnt_want_write+0xd7/0x2a0 fs/namespace.c:348 Code: bd 00 02 00 00 be 00 02 00 00 44 21 fe 31 ff e8 1f f4 98 ff 44 21 fd 75 0a e8 f5 ef 98 ff eb 3a 0f 1f 00 f3 90 42 0f b6 04 2b <84> c0 75 10 41 f7 06 00 02 00 00 74 1e e8 d7 ef 98 ff eb e5 44 89 RSP: 0018:ffffc90003acfda8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff11002261706 RCX: ffff8880197f0000 RDX: 0000000000000000 RSI: 0000000000000200 RDI: 0000000000000000 RBP: 0000000000000200 R08: ffffffff81eccb11 R09: fffffbfff1bc082e R10: fffffbfff1bc082e R11: 1ffffffff1bc082d R12: ffff88801130b820 R13: dffffc0000000000 R14: ffff88801130b830 R15: 0000000000000220 mnt_want_write+0x43/0x80 fs/namespace.c:394 path_setxattr+0x117/0x2b0 fs/xattr.c:593 __do_sys_setxattr fs/xattr.c:611 [inline] __se_sys_setxattr fs/xattr.c:607 [inline] __x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:607 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f418ef7cce9 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:00007f418ef0d2f8 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc RAX: ffffffffffffffda RBX: 00007f418f0044b0 RCX: 00007f418ef7cce9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000200 RBP: 00007f418efd2084 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e R13: 695f70756f72672c R14: 695f726573752c30 R15: 00007f418f0044b8 </TASK> ---------------- Code disassembly (best guess): 0: bd 00 02 00 00 mov $0x200,%ebp 5: be 00 02 00 00 mov $0x200,%esi a: 44 21 fe and %r15d,%esi d: 31 ff xor %edi,%edi f: e8 1f f4 98 ff callq 0xff98f433 14: 44 21 fd and %r15d,%ebp 17: 75 0a jne 0x23 19: e8 f5 ef 98 ff callq 0xff98f013 1e: eb 3a jmp 0x5a 20: 0f 1f 00 nopl (%rax) 23: f3 90 pause 25: 42 0f b6 04 2b movzbl (%rbx,%r13,1),%eax * 2a: 84 c0 test %al,%al <-- trapping instruction 2c: 75 10 jne 0x3e 2e: 41 f7 06 00 02 00 00 testl $0x200,(%r14) 35: 74 1e je 0x55 37: e8 d7 ef 98 ff callq 0xff98f013 3c: eb e5 jmp 0x23 3e: 44 rex.R 3f: 89 .byte 0x89 --- 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
