* [syzbot] [mm?] BUG: sleeping function called from invalid context in vma_alloc_folio_noprof (2)
@ 2026-05-03 11:47 syzbot
2026-05-04 0:13 ` Hillf Danton
0 siblings, 1 reply; 2+ messages in thread
From: syzbot @ 2026-05-03 11:47 UTC (permalink / raw)
To: Liam.Howlett, akpm, linux-kernel, linux-mm, ljs, shakeel.butt,
surenb, syzkaller-bugs, vbabka
Hello,
syzbot found the following issue on:
HEAD commit: dca922e019dd Merge tag 'xsa48x-7.1-tag' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=100242ce580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d0f0911eedbc130a
dashboard link: https://syzkaller.appspot.com/bug?extid=a21650c1666eae7b2aae
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
userspace arch: i386
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-dca922e0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1e719cb224ff/vmlinux-dca922e0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/79a541b03a9e/bzImage-dca922e0.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a21650c1666eae7b2aae@syzkaller.appspotmail.com
BUG: sleeping function called from invalid context at ./include/linux/sched/mm.h:323
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 5665, name: dhcpcd-run-hook
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
2 locks held by dhcpcd-run-hook/5665:
#0: ffff8880243d01c8 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x11d/0x590 mm/mmap_lock.c:310
#1: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#1: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#1: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x310 mm/pgtable-generic.c:290
CPU: 0 UID: 0 PID: 5665 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
__might_resched.cold+0x1ec/0x232 kernel/sched/core.c:9162
might_alloc include/linux/sched/mm.h:323 [inline]
prepare_alloc_pages+0x44a/0x5f0 mm/page_alloc.c:4995
__alloc_frozen_pages_noprof+0x19a/0x2bc0 mm/page_alloc.c:5215
alloc_pages_mpol+0x1fb/0x540 mm/mempolicy.c:2490
folio_alloc_mpol_noprof+0x36/0x260 mm/mempolicy.c:2509
vma_alloc_folio_noprof+0xed/0x1d0 mm/mempolicy.c:2544
folio_prealloc mm/memory.c:1193 [inline]
wp_page_copy mm/memory.c:3859 [inline]
do_wp_page+0x1ee1/0x4350 mm/memory.c:4320
handle_pte_fault mm/memory.c:6427 [inline]
__handle_mm_fault+0x1ab6/0x2a00 mm/memory.c:6549
handle_mm_fault+0x36d/0xa20 mm/memory.c:6718
do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f5a6f60980e
Code: df e8 d7 c4 ff ff 48 8d 3d 9c 92 05 00 31 c0 e8 e1 ca ff ff 95 75 24 48 8d 05 5e 9c 07 00 44 89 f2 4c 89 e6 48 89 df 48 8b 00 <83> a0 f8 02 00 00 00 e8 de eb ff ff e9 a8 00 00 00 48 85 db 0f 84
RSP: 002b:00007ffc0b5c63f0 EFLAGS: 00010246
RAX: 000055c4ea134910 RBX: 000055c4ea135c60 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 000055c4ea138c30 RDI: 000055c4ea135c60
RBP: 0000000000000000 R08: 00007f5a6f5b4b60 R09: 0000000000000000
R10: 0000000000000008 R11: 0000000000000246 R12: 000055c4ea138c30
R13: 000055c4ea135c60 R14: 0000000000000000 R15: 0000000000000000
</TASK>
================================================
WARNING: lock held when returning to user space!
syzkaller #0 Tainted: G W
------------------------------------------------
dhcpcd-run-hook/5665 is leaving the kernel with locks still held!
1 lock held by dhcpcd-run-hook/5665:
#0: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
#0: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
#0: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x310 mm/pgtable-generic.c:290
---
This report is generated by a bot. It may contain errors.
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^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [syzbot] [mm?] BUG: sleeping function called from invalid context in vma_alloc_folio_noprof (2)
2026-05-03 11:47 [syzbot] [mm?] BUG: sleeping function called from invalid context in vma_alloc_folio_noprof (2) syzbot
@ 2026-05-04 0:13 ` Hillf Danton
0 siblings, 0 replies; 2+ messages in thread
From: Hillf Danton @ 2026-05-04 0:13 UTC (permalink / raw)
To: syzbot; +Cc: Boqun Feng, linux-kernel, linux-mm, syzkaller-bugs, vbabka
> Date: Sun, 03 May 2026 04:47:26 -0700 [thread overview]
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: dca922e019dd Merge tag 'xsa48x-7.1-tag' of git://git.kerne..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=100242ce580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d0f0911eedbc130a
> dashboard link: https://syzkaller.appspot.com/bug?extid=a21650c1666eae7b2aae
> compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> userspace arch: i386
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-dca922e0.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/1e719cb224ff/vmlinux-dca922e0.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/79a541b03a9e/bzImage-dca922e0.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+a21650c1666eae7b2aae@syzkaller.appspotmail.com
>
> BUG: sleeping function called from invalid context at ./include/linux/sched/mm.h:323
> in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 5665, name: dhcpcd-run-hook
> preempt_count: 0, expected: 0
> RCU nest depth: 1, expected: 0
> 2 locks held by dhcpcd-run-hook/5665:
> #0: ffff8880243d01c8 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x11d/0x590 mm/mmap_lock.c:310
> #1: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
> #1: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
> #1: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x310 mm/pgtable-generic.c:290
> CPU: 0 UID: 0 PID: 5665 Comm: dhcpcd-run-hook Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:94 [inline]
> dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
> __might_resched.cold+0x1ec/0x232 kernel/sched/core.c:9162
> might_alloc include/linux/sched/mm.h:323 [inline]
> prepare_alloc_pages+0x44a/0x5f0 mm/page_alloc.c:4995
> __alloc_frozen_pages_noprof+0x19a/0x2bc0 mm/page_alloc.c:5215
> alloc_pages_mpol+0x1fb/0x540 mm/mempolicy.c:2490
> folio_alloc_mpol_noprof+0x36/0x260 mm/mempolicy.c:2509
> vma_alloc_folio_noprof+0xed/0x1d0 mm/mempolicy.c:2544
> folio_prealloc mm/memory.c:1193 [inline]
> wp_page_copy mm/memory.c:3859 [inline]
> do_wp_page+0x1ee1/0x4350 mm/memory.c:4320
Given pte_unmap_unlock() [1] before wp_page_copy(), the lockdep record
of rcu lock above looks false positive. Baffled.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/mm/memory.c#n4315
> handle_pte_fault mm/memory.c:6427 [inline]
> __handle_mm_fault+0x1ab6/0x2a00 mm/memory.c:6549
> handle_mm_fault+0x36d/0xa20 mm/memory.c:6718
> do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334
> handle_page_fault arch/x86/mm/fault.c:1474 [inline]
> exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527
> asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
> RIP: 0033:0x7f5a6f60980e
> Code: df e8 d7 c4 ff ff 48 8d 3d 9c 92 05 00 31 c0 e8 e1 ca ff ff 95 75 24 48 8d 05 5e 9c 07 00 44 89 f2 4c 89 e6 48 89 df 48 8b 00 <83> a0 f8 02 00 00 00 e8 de eb ff ff e9 a8 00 00 00 48 85 db 0f 84
> RSP: 002b:00007ffc0b5c63f0 EFLAGS: 00010246
> RAX: 000055c4ea134910 RBX: 000055c4ea135c60 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: 000055c4ea138c30 RDI: 000055c4ea135c60
> RBP: 0000000000000000 R08: 00007f5a6f5b4b60 R09: 0000000000000000
> R10: 0000000000000008 R11: 0000000000000246 R12: 000055c4ea138c30
> R13: 000055c4ea135c60 R14: 0000000000000000 R15: 0000000000000000
> </TASK>
>
> ================================================
> WARNING: lock held when returning to user space!
> syzkaller #0 Tainted: G W
> ------------------------------------------------
> dhcpcd-run-hook/5665 is leaving the kernel with locks still held!
> 1 lock held by dhcpcd-run-hook/5665:
> #0: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
> #0: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
> #0: ffffffff8e7e52e0 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x2f/0x310 mm/pgtable-generic.c:290
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-05-04 0:14 UTC | newest]
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2026-05-03 11:47 [syzbot] [mm?] BUG: sleeping function called from invalid context in vma_alloc_folio_noprof (2) syzbot
2026-05-04 0:13 ` Hillf Danton
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