[syzbot] [net?] WARNING in new_slab (3)
From: syzbot <hidden>
Date: 2026-09-30 21:58:37
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Hello, syzbot found the following issue on: HEAD commit: 6f8319e3e9a4 Merge tag 'mm-hotfixes-stable-2026-09-27-19-1.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=13af7df5580000 kernel config: https://syzkaller.appspot.com/x/.config?x=2a820d8842c77560 dashboard link: https://syzkaller.appspot.com/bug?extid=f95c2f0a71a98cef50eb 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-6f8319e3.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/91b951779fc3/vmlinux-6f8319e3.xz kernel image: https://storage.googleapis.com/syzbot-assets/18319ae672c1/bzImage-6f8319e3.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+f95c2f0a71a98cef50eb@syzkaller.appspotmail.com ------------[ 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> --- 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