Messages in this thread | | | From | Dmitry Vyukov <> | Date | Sat, 5 Jun 2021 15:09:40 +0200 | Subject | Re: [syzbot] WARNING: suspicious RCU usage in __ext4_mark_inode_dirty |
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On Sat, Jun 5, 2021 at 8:47 AM syzbot <syzbot+290af4ba353cd50ec3d3@syzkaller.appspotmail.com> wrote: > > Hello, > > syzbot found the following issue on: > > HEAD commit: f88cd3fb Merge tag 'vfio-v5.13-rc5' of git://github.com/aw.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1187ac33d00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=8a9e9956ca52a5f6 > dashboard link: https://syzkaller.appspot.com/bug?extid=290af4ba353cd50ec3d3 > > Unfortunately, I don't have any reproducer for this issue yet. > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+290af4ba353cd50ec3d3@syzkaller.appspotmail.com
Another rcu/lockdep false positive:
#syz fix: rcu: Reject RCU_LOCKDEP_WARN() false positives
> Process accounting resumed > Process accounting resumed > ============================= > WARNING: suspicious RCU usage > 5.13.0-rc4-syzkaller #0 Not tainted > ----------------------------- > kernel/sched/core.c:8304 Illegal context switch in RCU-bh read-side critical section! > > other info that might help us debug this: > > > rcu_scheduler_active = 2, debug_locks = 0 > 3 locks held by syz-executor.1/20572: > #0: > ffff88801dae7500 (&acct->lock#2){+.+.}-{3:3}, at: acct_get kernel/acct.c:161 [inline] > ffff88801dae7500 (&acct->lock#2){+.+.}-{3:3}, at: slow_acct_process kernel/acct.c:576 [inline] > ffff88801dae7500 (&acct->lock#2){+.+.}-{3:3}, at: acct_process+0x213/0x4f0 kernel/acct.c:602 > #1: ffff8880290ca460 (sb_writers#5){.+.+}-{0:0}, at: slow_acct_process kernel/acct.c:578 [inline] > #1: ffff8880290ca460 (sb_writers#5){.+.+}-{0:0}, at: acct_process+0x3b7/0x4f0 kernel/acct.c:602 > #2: ffff8880752da270 (&sb->s_type->i_mutex_key#10){++++}-{3:3}, at: inode_lock include/linux/fs.h:774 [inline] > #2: ffff8880752da270 (&sb->s_type->i_mutex_key#10){++++}-{3:3}, at: ext4_buffered_write_iter+0xb6/0x4d0 fs/ext4/file.c:263 > > stack backtrace: > CPU: 1 PID: 20572 Comm: syz-executor.1 Not tainted 5.13.0-rc4-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0x141/0x1d7 lib/dump_stack.c:120 > ___might_sleep+0x229/0x2c0 kernel/sched/core.c:8304 > __ext4_mark_inode_dirty+0xea/0x8d0 fs/ext4/inode.c:5908 > ext4_dirty_inode+0xd4/0x110 fs/ext4/inode.c:5947 > __mark_inode_dirty+0x6e3/0x10f0 fs/fs-writeback.c:2274 > mark_inode_dirty include/linux/fs.h:2404 [inline] > generic_write_end+0x316/0x4f0 fs/buffer.c:2223 > ext4_da_write_end+0x20f/0xb50 fs/ext4/inode.c:3110 > generic_perform_write+0x2c0/0x4f0 mm/filemap.c:3671 > ext4_buffered_write_iter+0x244/0x4d0 fs/ext4/file.c:269 > ext4_file_write_iter+0x423/0x14e0 fs/ext4/file.c:680 > __kernel_write+0x58d/0xa90 fs/read_write.c:550 > do_acct_process+0xd0a/0x1420 kernel/acct.c:519 > slow_acct_process kernel/acct.c:578 [inline] > acct_process+0x3b7/0x4f0 kernel/acct.c:602 > do_exit+0x1979/0x2a60 kernel/exit.c:816 > do_group_exit+0x125/0x310 kernel/exit.c:923 > get_signal+0x47f/0x2150 kernel/signal.c:2835 > arch_do_signal_or_restart+0x2a8/0x1eb0 arch/x86/kernel/signal.c:789 > handle_signal_work kernel/entry/common.c:147 [inline] > exit_to_user_mode_loop kernel/entry/common.c:171 [inline] > exit_to_user_mode_prepare+0x171/0x280 kernel/entry/common.c:208 > __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] > syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301 > do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:57 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x4665d9 > Code: Unable to access opcode bytes at RIP 0x4665af. > RSP: 002b:00007effc6b68218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca > RAX: fffffffffffffe00 RBX: 000000000056c040 RCX: 00000000004665d9 > RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000056c040 > RBP: 000000000056c038 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056c044 > R13: 00007fff3643907f R14: 00007effc6b68300 R15: 0000000000022000 > > > --- > 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@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/00000000000009a40d05c3ff2ebc%40google.com.
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