syzbot


WARNING: suspicious RCU usage in getname_flags

Status: fixed on 2021/11/10 00:50
Reported-by: syzbot+dde0cc33951735441301@syzkaller.appspotmail.com
Fix commit: 3066820034b5 rcu: Reject RCU_LOCKDEP_WARN() false positives
First crash: 673d, last: 578d
duplicates (10):
Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
WARNING: suspicious RCU usage in lock_sock_nested 1 672d 668d 0/24 closed as dup on 2021/04/13 18:10
WARNING: suspicious RCU usage in list_lru_destroy 1 673d 669d 0/24 closed as dup on 2021/04/05 03:03
WARNING: suspicious RCU usage in dput 2 608d 670d 0/24 closed as dup on 2021/04/05 03:05
WARNING: suspicious RCU usage in clear_huge_page 19 604d 669d 0/24 closed as dup on 2021/04/05 03:03
WARNING: suspicious RCU usage in do_user_addr_fault 3 588d 668d 0/24 closed as dup on 2021/04/13 18:11
WARNING: suspicious RCU usage in copy_page_range 1 678d 673d 0/24 closed as dup on 2021/04/13 18:12
WARNING: suspicious RCU usage in copy_pte_range 1 674d 670d 0/24 closed as dup on 2021/04/13 18:11
WARNING: suspicious RCU usage in remove_vma (2) 1 674d 670d 0/24 closed as dup on 2021/04/05 03:04
WARNING: suspicious RCU usage in __schedule 5 589d 670d 0/24 closed as dup on 2021/04/13 18:11
WARNING: suspicious RCU usage in find_inlist_lock 1 674d 670d 0/24 closed as dup on 2021/04/13 18:12

Sample crash report:
WARNING: suspicious RCU usage
5.12.0-rc5-syzkaller #0 Not tainted
-----------------------------
kernel/sched/core.c:8294 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 systemd-udevd/4825.

stack backtrace:
CPU: 0 PID: 4825 Comm: systemd-udevd Not tainted 5.12.0-rc5-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:8294
 __might_fault+0x6e/0x180 mm/memory.c:5018
 strncpy_from_user+0x2f/0x3e0 lib/strncpy_from_user.c:117
 getname_flags.part.0+0x95/0x4f0 fs/namei.c:149
 getname_flags fs/namei.c:2733 [inline]
 user_path_at_empty+0xa1/0x100 fs/namei.c:2733
 user_path_at include/linux/namei.h:60 [inline]
 do_faccessat+0x127/0x850 fs/open.c:425
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f840445f9c7
Code: 83 c4 08 48 3d 01 f0 ff ff 73 01 c3 48 8b 0d c8 d4 2b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 b8 15 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a1 d4 2b 00 f7 d8 64 89 01 48
RSP: 002b:00007ffdc40178d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015
RAX: ffffffffffffffda RBX: 0000564d558c9760 RCX: 00007f840445f9c7
RDX: 00746e657665752f RSI: 0000000000000000 RDI: 00007ffdc40178e0
RBP: 00007ffdc4017960 R08: 0000000000004400 R09: 0000000000001010
R10: 0000000000000020 R11: 0000000000000246 R12: 0000564d557b1856
R13: 0000564d558ed190 R14: 00007ffdc40178e0 R15: 0000564d558fe590

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets Title
ci-upstream-kasan-gce-selinux-root 2021/03/31 04:11 upstream 2bb25b3a748a 6a81331a .config console log report info WARNING: suspicious RCU usage in getname_flags
ci-upstream-kasan-gce-386 2021/07/04 03:41 upstream 3dbdb38e2869 55aa55c2 .config console log report info WARNING: suspicious RCU usage in getname_flags
* Struck through repros no longer work on HEAD.