syzbot


WARNING: suspicious RCU usage in __get_free_pages

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: 1142d, last: 1142d

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
2 locks held by kworker/u4:5/200:
 #0: 
ffff888011069138
 (
(wq_completion)events_unbound
){+.+.}-{0:0}
, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
, at: set_work_data kernel/workqueue.c:616 [inline]
, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
, at: process_one_work+0x871/0x1600 kernel/workqueue.c:2246
 #1: 
ffffc900017dfda8
 (
(work_completion)(&sub_info->work)
){+.+.}-{0:0}
, at: process_one_work+0x8a5/0x1600 kernel/workqueue.c:2250

stack backtrace:
CPU: 1 PID: 200 Comm: kworker/u4:5 Not tainted 5.12.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_unbound call_usermodehelper_exec_work
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
 prepare_alloc_pages mm/page_alloc.c:4947 [inline]
 __alloc_pages_nodemask+0x48a/0x730 mm/page_alloc.c:4991
 alloc_pages_current+0x18c/0x2a0 mm/mempolicy.c:2277
 alloc_pages include/linux/gfp.h:561 [inline]
 __get_free_pages+0x8/0x40 mm/page_alloc.c:5044
 kasan_populate_vmalloc_pte mm/kasan/shadow.c:260 [inline]
 kasan_populate_vmalloc_pte+0x25/0x160 mm/kasan/shadow.c:251
 apply_to_pte_range mm/memory.c:2414 [inline]
 apply_to_pmd_range mm/memory.c:2450 [inline]
 apply_to_pud_range mm/memory.c:2478 [inline]
 apply_to_p4d_range mm/memory.c:2506 [inline]
 __apply_to_page_range+0x645/0xdf0 mm/memory.c:2533
 alloc_vmap_area+0xb0a/0x1e10 mm/vmalloc.c:1243
 __get_vm_area_node+0x128/0x380 mm/vmalloc.c:2096
 __vmalloc_node_range+0xcb/0x170 mm/vmalloc.c:2571
 alloc_thread_stack_node kernel/fork.c:244 [inline]
 dup_task_struct kernel/fork.c:864 [inline]
 copy_process+0x8de/0x70f0 kernel/fork.c:1949
 kernel_clone+0xe7/0xab0 kernel/fork.c:2502
 kernel_thread+0xb5/0xf0 kernel/fork.c:2554
 call_usermodehelper_exec_sync kernel/umh.c:133 [inline]
 call_usermodehelper_exec_work+0x69/0x180 kernel/umh.c:164
 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:313
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/05/04 12:55 upstream d2b6f8a17919 09efdd63 .config console log report info ci-upstream-kasan-gce-386 WARNING: suspicious RCU usage in __get_free_pages
* Struck through repros no longer work on HEAD.