WARNING in bitmap_parse_user

Status: premoderation: reported C repro on 2026/07/30 09:20
Reported-by: syzbot+336fc9f8bcc9db1e8405@syzkaller.appspotmail.com
First crash: 8d03h, last: 4h21m
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in bitmap_parse_user -1 syz, C 3 23h30m 1d00h 0/3 upstream: reported C repro on 2026/08/06 12:00
linux-6.1 WARNING in bitmap_parse_user -1 syz, C 5 1d07h 7d08h 0/3 upstream: reported C repro on 2026/07/31 03:46
linux-6.6 WARNING in bitmap_parse_user -1 syz, C 5 1d08h 7d08h 0/2 upstream: reported C repro on 2026/07/31 03:39
upstream WARNING in bitmap_parse_user trace -1 syz, C 83 579d 599d 28/29 fixed on 2025/05/06 15:33

Sample crash report:
WARNING: CPU: 0 PID: 313 at mm/page_alloc.c:5285 __alloc_pages_noprof+0x109/0x7e0 mm/page_alloc.c:5285
Modules linked in:
CPU: 0 UID: 0 PID: 313 Comm: syz-executor232 Not tainted syzkaller #0 28dc4f15f82f041c91cead1444746a7bfe1433af
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:__alloc_pages_noprof+0x109/0x7e0 mm/page_alloc.c:5285
Code: 00 0f 1f 44 00 00 83 fb 0b 72 28 b8 00 20 00 00 23 44 24 40 75 1d 80 3d d4 d8 0b 06 00 0f 85 c2 00 00 00 c6 05 c7 d8 0b 06 01 <0f> 0b 31 c0 e9 b4 00 00 00 83 fb 0a 0f 87 a9 00 00 00 44 8b 64 24
RSP: 0018:ffffc9000120f8c0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000013 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc9000120f978
RBP: ffffc9000120f9f0 R08: ffffc9000120f977 R09: 0000000000000000
R10: ffffc9000120f960 R11: fffff52000241f2f R12: ffffc9000120f900
R13: dffffc0000000000 R14: 1ffff92000241f1c R15: 0000000000000000
FS:  00005555564ad3c0(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005599c0ddd000 CR3: 000000012e664000 CR4: 00000000003526b0
Call Trace:
 <TASK>
 ___kmalloc_large_node+0x81/0x220 mm/slub.c:-1
 __kmalloc_large_node_noprof+0x1e/0xd0 mm/slub.c:4367
 __do_kmalloc_node mm/slub.c:4383 [inline]
 __kmalloc_node_track_caller_noprof+0x30d/0x4f0 mm/slub.c:4414
 memdup_user_nul+0x40/0x1a0 mm/util.c:319
 bitmap_parse_user+0x29/0x80 lib/bitmap-str.c:31
 cpumask_parse_user include/linux/cpumask.h:876 [inline]
 write_irq_affinity kernel/irq/proc.c:151 [inline]
 irq_affinity_proc_write+0x139/0x230 kernel/irq/proc.c:180
 pde_write fs/proc/inode.c:330 [inline]
 proc_reg_write+0x1f7/0x2f0 fs/proc/inode.c:342
 vfs_write+0x3c1/0xfd0 fs/read_write.c:682
 ksys_write+0x145/0x260 fs/read_write.c:737
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x7f/0x90 fs/read_write.c:746
 x64_sys_call+0x271c/0x2ee0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:47 [inline]
 do_syscall_64+0x57/0xf0 arch/x86/entry/common.c:78
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f44065ffc39
Code: c0 79 93 eb d5 48 8d 7c 1d 00 eb 99 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 d8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe10e0e3a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000020000000

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/07 08:08 android16-6.12 282da3f968e5 c38879ea .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in bitmap_parse_user
2026/08/07 00:19 android16-6.12 749a6f9d41aa c38879ea .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in bitmap_parse_user
2026/08/06 22:43 android16-6.12 749a6f9d41aa c38879ea .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in bitmap_parse_user
2026/08/05 09:06 android16-6.12 f068f96e8cc3 52aa2820 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in bitmap_parse_user
2026/07/30 09:48 android16-6.12 f1c9c21d1c2f 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in bitmap_parse_user
2026/07/30 09:33 android16-6.12 f1c9c21d1c2f 2377cd3d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in bitmap_parse_user
2026/08/06 01:24 android16-6.12 1d5d2bee38d2 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in bitmap_parse_user
2026/08/06 01:24 android16-6.12 1d5d2bee38d2 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in bitmap_parse_user
2026/07/30 09:20 android16-6.12 f1c9c21d1c2f 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in bitmap_parse_user
2026/07/30 09:19 android16-6.12 f1c9c21d1c2f 2377cd3d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-12-rust WARNING in bitmap_parse_user
* Struck through repros no longer work on HEAD.