syzbot
WARNING in bitmap_parse_user
Status:
upstream: reported C repro on 2026/07/31 03:39
Bug presence:
origin:lts-only
[Documentation on labels]
Reported-by: syzbot+304ce94b7efa3a6313d4@syzkaller.appspotmail.com
First crash: 9d19h, last: 18h03m
Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5932 at mm/page_alloc.c:4477 __alloc_pages+0x2e4/0x460 mm/page_alloc.c:4477
Modules linked in:
CPU: 1 PID: 5932 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__alloc_pages+0x2e4/0x460 mm/page_alloc.c:4477
Code: 0c 25 28 00 00 00 48 3b 8c 24 a0 00 00 00 0f 85 9f 00 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 c6 05 92 1b a3 0c 01 <0f> 0b eb a4 a9 00 00 08 00 8b 74 24 0c 75 3e 44 89 f1 81 e1 7f ff
RSP: 0018:ffffc90003377a20 EFLAGS: 00010246
RAX: ffffc90003377a00 RBX: 1ffff9200066ef48 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc90003377a88
RBP: ffffc90003377b10 R08: ffffc90003377a87 R09: 0000000000000000
R10: ffffc90003377a60 R11: fffff5200066ef51 R12: 0000000000000013
R13: 0000000000000000 R14: 0000000000040cc0 R15: dffffc0000000000
FS: 0000555594ccd500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2ce63fff CR3: 0000000074291000 CR4: 00000000003506e0
Call Trace:
<TASK>
__alloc_pages_node include/linux/gfp.h:237 [inline]
alloc_pages_node include/linux/gfp.h:260 [inline]
__kmalloc_large_node+0x8c/0x1f0 mm/slab_common.c:1148
__do_kmalloc_node mm/slab_common.c:995 [inline]
__kmalloc_node_track_caller+0x110/0x230 mm/slab_common.c:1027
memdup_user_nul+0x2c/0xf0 mm/util.c:284
bitmap_parse_user+0x23/0x70 lib/bitmap.c:464
cpumask_parse_user include/linux/cpumask.h:777 [inline]
write_irq_affinity kernel/irq/proc.c:153 [inline]
irq_affinity_proc_write+0x13c/0x230 kernel/irq/proc.c:182
pde_write fs/proc/inode.c:340 [inline]
proc_reg_write+0x1e4/0x2d0 fs/proc/inode.c:352
vfs_write+0x299/0x9a0 fs/read_write.c:582
ksys_write+0x151/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f691119e019
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdd517c918 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f6911425fa0 RCX: 00007f691119e019
RDX: 00000000fffffdd4 RSI: 0000200000000340 RDI: 0000000000000003
RBP: 00007f691123500c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6911425fac R14: 00007f6911425fa0 R15: 00007f6911425fa0
</TASK>
* Struck through repros no longer work on HEAD.