Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 10 Apr 2024 11:45:29 -0700 | Subject | [syzbot] [net?] possible deadlock in unix_notinflight | From | syzbot <> |
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Hello,
syzbot found the following issue on:
HEAD commit: 443574b03387 riscv, bpf: Fix kfunc parameters incompatibil.. git tree: bpf console+strace: https://syzkaller.appspot.com/x/log.txt?x=12898aa9180000 kernel config: https://syzkaller.appspot.com/x/.config?x=6fb1be60a193d440 dashboard link: https://syzkaller.appspot.com/bug?extid=38b3aa8cd529958bd27a compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13d693e3180000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11aee305180000
Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/3f355021a085/disk-443574b0.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/44cf4de7472a/vmlinux-443574b0.xz kernel image: https://storage.googleapis.com/syzbot-assets/a99a36c7ad65/bzImage-443574b0.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+38b3aa8cd529958bd27a@syzkaller.appspotmail.com
============================================ WARNING: possible recursive locking detected 6.8.0-syzkaller-05236-g443574b03387 #0 Not tainted -------------------------------------------- kworker/u8:0/10 is trying to acquire lock: ffffffff8f48b798 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffffffff8f48b798 (unix_gc_lock){+.+.}-{2:2}, at: unix_notinflight+0x204/0x390 net/unix/garbage.c:140
but task is already holding lock: ffffffff8f48b798 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] ffffffff8f48b798 (unix_gc_lock){+.+.}-{2:2}, at: __unix_gc+0x117/0xf10 net/unix/garbage.c:261
other info that might help us debug this: Possible unsafe locking scenario:
CPU0 ---- lock(unix_gc_lock); lock(unix_gc_lock);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by kworker/u8:0/10: #0: ffff888014c81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3229 [inline] #0: ffff888014c81148 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x8e0/0x1770 kernel/workqueue.c:3335 #1: ffffc900000f7d00 (unix_gc_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3230 [inline] #1: ffffc900000f7d00 (unix_gc_work){+.+.}-{0:0}, at: process_scheduled_works+0x91b/0x1770 kernel/workqueue.c:3335 #2: ffffffff8f48b798 (unix_gc_lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #2: ffffffff8f48b798 (unix_gc_lock){+.+.}-{2:2}, at: __unix_gc+0x117/0xf10 net/unix/garbage.c:261
stack backtrace: CPU: 1 PID: 10 Comm: kworker/u8:0 Not tainted 6.8.0-syzkaller-05236-g443574b03387 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Workqueue: events_unbound __unix_gc Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 check_deadlock kernel/locking/lockdep.c:3062 [inline] validate_chain+0x15c1/0x58e0 kernel/locking/lockdep.c:3856 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1e4/0x530 kernel/locking/lockdep.c:5754 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] unix_notinflight+0x204/0x390 net/unix/garbage.c:140 unix_detach_fds net/unix/af_unix.c:1819 [inline] unix_destruct_scm+0x221/0x350 net/unix/af_unix.c:1876 skb_release_head_state+0x100/0x250 net/core/skbuff.c:1188 skb_release_all net/core/skbuff.c:1200 [inline] __kfree_skb net/core/skbuff.c:1216 [inline] kfree_skb_reason+0x15d/0x390 net/core/skbuff.c:1252 kfree_skb include/linux/skbuff.h:1267 [inline] __unix_gc+0xaf3/0xf10 net/unix/garbage.c:330 process_one_work kernel/workqueue.c:3254 [inline] process_scheduled_works+0xa00/0x1770 kernel/workqueue.c:3335 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416 kthread+0x2f0/0x390 kernel/kthread.c:388 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243 </TASK>
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