syzbot


WARNING: suspicious RCU usage in vm_mmap_pgoff

Status: fixed on 2021/11/10 00:50
Subsystems: mm
[Documentation on labels]
Fix commit: 3066820034b5 rcu: Reject RCU_LOCKDEP_WARN() false positives
First crash: 1097d, last: 1097d

Sample crash report:
=============================
WARNING: suspicious RCU usage
5.13.0-rc3-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
no locks held by syz-executor.1/28715.

stack backtrace:
CPU: 1 PID: 28715 Comm: syz-executor.1 Not tainted 5.13.0-rc3-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+0x202/0x31e lib/dump_stack.c:120
 ___might_sleep+0xce/0x6b0 kernel/sched/core.c:8304
 down_write_killable+0x7e/0x1b0 kernel/locking/rwsem.c:1416
 mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
 vm_mmap_pgoff+0x14d/0x2b0 mm/util.c:517
 ksys_mmap_pgoff+0x504/0x7b0 mm/mmap.c:1638
 do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x466622
Code: 00 00 00 00 00 0f 1f 00 41 f7 c1 ff 0f 00 00 75 27 55 48 89 fd 53 89 cb 48 85 ff 74 3b 41 89 da 48 89 ef b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 5b 5d c3 0f 1f 00 48 c7 c0 bc ff ff ff 64
RSP: 002b:00007f577489a0f8 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 0000000000008011 RCX: 0000000000466622
RDX: 0000000000000003 RSI: 0000000000120140 RDI: 0000000020ff7000
RBP: 0000000020ff7000 R08: 0000000000000003 R09: 0000000000000000
R10: 0000000000008011 R11: 0000000000000206 R12: 0000000020000300
R13: 0000000020ff7000 R14: 00000000200002c0 R15: 0000000020ff7000

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/05/28 20:36 upstream 97e5bf604b7a 858ea628 .config console log report info ci-upstream-kasan-gce-smack-root WARNING: suspicious RCU usage in vm_mmap_pgoff
* Struck through repros no longer work on HEAD.