syzbot


WARNING: suspicious RCU usage in __alloc_file

Status: fixed on 2021/11/10 00:50
Reported-by: syzbot+@syzkaller.appspotmail.com
Fix commit: 3066820034b5 rcu: Reject RCU_LOCKDEP_WARN() false positives
First crash: 633d, last: 633d

Sample crash report:
=============================
WARNING: suspicious RCU usage
5.12.0-syzkaller #0 Not tainted
-----------------------------
kernel/sched/core.c:8304 Illegal context switch in RCU-sched read-side critical section!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 0
no locks held by syz-executor.3/20998.

stack backtrace:
CPU: 0 PID: 20998 Comm: syz-executor.3 Not tainted 5.12.0-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+0x266/0x2c0 kernel/sched/core.c:8304
 might_alloc include/linux/sched/mm.h:197 [inline]
 slab_pre_alloc_hook mm/slab.h:497 [inline]
 slab_alloc_node mm/slub.c:2827 [inline]
 slab_alloc mm/slub.c:2916 [inline]
 kmem_cache_alloc+0x2c3/0x370 mm/slub.c:2921
 kmem_cache_zalloc include/linux/slab.h:676 [inline]
 __alloc_file+0x21/0x280 fs/file_table.c:101
 alloc_empty_file+0x6d/0x170 fs/file_table.c:150
 alloc_file+0x5e/0x5a0 fs/file_table.c:192
 alloc_file_pseudo+0x165/0x250 fs/file_table.c:232
 sock_alloc_file+0x4f/0x190 net/socket.c:412
 __sys_socketpair+0x2fb/0x570 net/socket.c:1583
 __do_sys_socketpair net/socket.c:1612 [inline]
 __se_sys_socketpair net/socket.c:1609 [inline]
 __x64_sys_socketpair+0x93/0xf0 net/socket.c:1609
 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665f9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f13f314c188 EFLAGS: 00000246
 ORIG_RAX: 0000000000000035
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 00000000004665f9
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000001
RBP: 00000000004bfce1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000020000180 R11: 0000000000000246 R12: 000000000056bf60
R13: 0000000000a9fb1f R14: 00007f13f314c300 R15: 0000000000022000

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci-upstream-kasan-gce 2021/05/06 11:25 upstream d2b6f8a17919 06c27ff5 .config console log report info WARNING: suspicious RCU usage in __alloc_file
* Struck through repros no longer work on HEAD.