WARNING: suspicious RCU usage in copy_page

WARNING: suspicious RCU usage in copy_page_range
Status: closed as dup on 2021/04/13 18:12
Reported-by: syzbot+1a33233ccd8201ec2322@syzkaller.appspotmail.com
First crash: 27d, last: 27d

Duplicate of (1):
Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported
WARNING: suspicious RCU usage in getname_flags				1	23d	19d

Sample crash report:

=============================
WARNING: suspicious RCU usage
5.12.0-rc4-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
3 locks held by syz-executor.0/8401:
 #0: ffffffff8c03e5b0 (dup_mmap_sem){++++}-{0:0}, at: dup_mmap kernel/fork.c:479 [inline]
 #0: ffffffff8c03e5b0 (dup_mmap_sem){++++}-{0:0}, at: dup_mm+0x108/0x1380 kernel/fork.c:1368
 #1: ffff888018d08858 (&mm->mmap_lock#2){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:87 [inline]
 #1: ffff888018d08858 (&mm->mmap_lock#2){++++}-{3:3}, at: dup_mmap kernel/fork.c:480 [inline]
 #1: ffff888018d08858 (&mm->mmap_lock#2){++++}-{3:3}, at: dup_mm+0x12e/0x1380 kernel/fork.c:1368
 #2: ffff88801888c058 (&mm->mmap_lock/1){+.+.}-{3:3}, at: mmap_write_lock_nested include/linux/mmap_lock.h:78 [inline]
 #2: ffff88801888c058 (&mm->mmap_lock/1){+.+.}-{3:3}, at: dup_mmap kernel/fork.c:489 [inline]
 #2: ffff88801888c058 (&mm->mmap_lock/1){+.+.}-{3:3}, at: dup_mm+0x18a/0x1380 kernel/fork.c:1368

stack backtrace:
CPU: 0 PID: 8401 Comm: syz-executor.0 Not tainted 5.12.0-rc4-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
 copy_pte_range mm/memory.c:1010 [inline]
 copy_pmd_range mm/memory.c:1064 [inline]
 copy_pud_range mm/memory.c:1101 [inline]
 copy_p4d_range mm/memory.c:1125 [inline]
 copy_page_range+0x1270/0x3fd0 mm/memory.c:1198
 dup_mmap kernel/fork.c:594 [inline]
 dup_mm+0x9ed/0x1380 kernel/fork.c:1368
 copy_mm kernel/fork.c:1424 [inline]
 copy_process+0x2b99/0x7150 kernel/fork.c:2107
 kernel_clone+0xe7/0xab0 kernel/fork.c:2500
 __do_sys_clone+0xc8/0x110 kernel/fork.c:2617
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x464a4b
Code: ed 0f 85 60 01 00 00 64 4c 8b 0c 25 10 00 00 00 45 31 c0 4d 8d 91 d0 02 00 00 31 d2 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 89 00 00 00 41 89 c5 85 c0 0f 85 90 00 00
RSP: 002b:00007ffd44303270 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000464a4b
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000002e94400
R10: 0000000002e946d0 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffd44303360

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-upstream-kasan-gce-root	2021/03/26 22:17	upstream	db24726b	a8529b82	.config	log	report			info	WARNING: suspicious RCU usage in copy_page_range