WARNING in new_slab (3)

Status: upstream: reported on 2026/09/30 21:58
Subsystems: net
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+f95c2f0a71a98cef50eb@syzkaller.appspotmail.com
First crash: 1d21h, last: 1d21h
▶ ▼ ✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
4f9baec6 assessment-security DenialOfService: ❌ Exploitable: ❌ FilesystemTrigger: ❌ NetworkTrigger: ✅ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ WARNING in new_slab (3) 2026/10/01 01:02 2026/10/01 01:02 2026/10/01 01:38 38f7f0d1
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH v1 net] ref_tracker: Don't use __GFP_NOFAIL for PF_MEMALLOC thread. 2 (2) 2026/10/01 06:51
[syzbot] [net?] WARNING in new_slab (3) 0 (1) 2026/09/30 21:58
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in new_slab mm -1 syz, C inconclusive 2 1715d 1745d 20/29 fixed on 2022/03/08 16:11
upstream WARNING in new_slab (2) mm -1 6 343d 396d 0/29 closed as dup on 2025/08/31 01:45

Sample crash report:
------------[ cut here ]------------
current->flags & PF_MEMALLOC
WARNING: mm/page_alloc.c:4816 at __alloc_pages_slowpath mm/page_alloc.c:4816 [inline], CPU#0: cifsd/12032
WARNING: mm/page_alloc.c:4816 at __alloc_frozen_pages_noprof+0x1eac/0x3300 mm/page_alloc.c:5449, CPU#0: cifsd/12032
Modules linked in:
CPU: 0 UID: 0 PID: 12032 Comm: cifsd Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:__alloc_pages_slowpath mm/page_alloc.c:4816 [inline]
RIP: 0010:__alloc_frozen_pages_noprof+0x1eac/0x3300 mm/page_alloc.c:5449
Code: 38 d0 7c 08 84 d2 0f 85 de 12 00 00 65 48 8b 05 e2 a7 1c 12 c7 84 24 94 00 00 00 00 80 00 00 f6 40 2d 08 0f 84 ba e7 ff ff 90 <0f> 0b 90 e9 b1 e7 ff ff 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03
RSP: 0000:ffffc90002e172d0 EFLAGS: 00010202
RAX: ffff888029380000 RBX: 0000000000000000 RCX: 1ffff1100fffad29
RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff88803fffd938
RBP: ffff88802938002c R08: 0000000000008000 R09: 0000000000000001
R10: 0000000000000002 R11: 0000000000000000 R12: 00000000000cac40
R13: ffff88803fffb900 R14: 0000000000000000 R15: 1ffff920005c2e74
FS:  0000000000000000(0000) GS:ffff888096955000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000008000a000 CR3: 00000000403b5000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 alloc_slab_page mm/slub.c:3347 [inline]
 allocate_slab mm/slub.c:3470 [inline]
 new_slab+0x1f6/0x6e0 mm/slub.c:3513
 refill_objects+0xe3/0x410 mm/slub.c:7417
 refill_sheaf mm/slub.c:2885 [inline]
 __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4774
 alloc_from_pcs mm/slub.c:4850 [inline]
 slab_alloc_node mm/slub.c:4984 [inline]
 __kmalloc_cache_noprof+0x4f4/0x6d0 mm/slub.c:5559
 _kmalloc_noprof include/linux/slab.h:991 [inline]
 _kzalloc_noprof include/linux/slab.h:1312 [inline]
 ref_tracker_alloc+0x190/0x590 lib/ref_tracker.c:270
 __netns_tracker_alloc include/net/net_namespace.h:370 [inline]
 sk_alloc+0xcfc/0xe80 net/core/sock.c:2329
 inet_create net/ipv4/af_inet.c:333 [inline]
 inet_create+0x3a0/0x1060 net/ipv4/af_inet.c:259
 __sock_create+0x339/0x860 net/socket.c:1676
 generic_ip_connect+0x826/0x1810 fs/smb/client/connect.c:3377
 __cifs_reconnect+0x348/0xa80 fs/smb/client/connect.c:420
 _cifs_reconnect fs/smb/client/connect.c:596 [inline]
 cifs_reconnect fs/smb/client/connect.c:610 [inline]
 cifs_readv_from_socket+0x7c1/0xa30 fs/smb/client/connect.c:749
 cifs_read_from_socket+0xb8/0x100 fs/smb/client/connect.c:804
 cifs_demultiplex_thread+0x2db/0x2ea0 fs/smb/client/connect.c:1295
 kthread+0x373/0x450 kernel/kthread.c:436
 ret_from_fork+0x730/0xd60 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/29 23:34 upstream 6f8319e3e9a4 328436b3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in new_slab
* Struck through repros no longer work on HEAD.