On Sat, May 09, 2026 at 12:35:24PM -0700, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit: 9207d47f966b Merge tag 'for-linus' of git://git.kernel.org..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=17e44d06580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=d0f0911eedbc130a
> dashboard link: https://syzkaller.appspot.com/bug?extid=8b12fc6e0fb139765b58
> 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-9207d47f.raw.xz
> vmlinux:
> https://storage.googleapis.com/syzbot-assets/6c5e883f31aa/vmlinux-9207d47f.xz
> kernel image:
> https://storage.googleapis.com/syzbot-assets/19f3e863ae5c/bzImage-9207d47f.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email protected]
>
> ------------[ cut here ]------------
> kernel BUG at mm/vmalloc.c:3206!
It seems that this bug was fixed by commit 30c19366636f ("mm: fix BUG
splat with kvmalloc + GFP_ATOMIC"), but then commit c6307674ed82 ("mm:
kvmalloc: add non-blocking support for vmalloc") re-introduced it.
Uladzislau, can you please look into it?
Note that the bridge is calling rhashtable_lookup_insert_fast() with BH
disabled.
Thanks
> Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
> CPU: 1 UID: 0 PID: 8030 Comm: syz.6.9336 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:__get_vm_area_node+0x2d2/0x330 mm/vmalloc.c:3206
> Code: 03 80 3c 11 00 75 5c 48 89 43 08 e9 4b ff ff ff e8 43 a8 a4 ff 48 89 df
> e8 db 98 05 00 31 db e9 37 ff ff ff e8 2f a8 a4 ff 90 <0f> 0b e8 77 6b 11 00
> e9 9e fe ff ff e8 6d 6b 11 00 e9 71 fe ff ff
> RSP: 0018:ffffc90006f76860 EFLAGS: 00010246
> RAX: 0000000000080000 RBX: 0000000000000200 RCX: ffffc90034405000
> RDX: 0000000000080000 RSI: ffffffff82633fb1 RDI: ffff8880244b4a00
> RBP: 000000000000000c R08: 0000000000000005 R09: 0000000000000000
> R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000022
> R13: 0000000000008080 R14: 0000000000000001 R15: 0000000000000000
> FS: 0000000000000000(0000) GS:ffff88809727d000(0063) knlGS:00000000f4f61b40
> CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
> CR2: 00000000f73c4f50 CR3: 0000000055b77000 CR4: 0000000000352ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Call Trace:
> <TASK>
> __vmalloc_node_range_noprof+0x228/0x1630 mm/vmalloc.c:4024
> __kvmalloc_node_noprof+0x3de/0xa00 mm/slub.c:6860
> bucket_table_alloc.isra.0+0x88/0x460 lib/rhashtable.c:186
> rhashtable_insert_rehash lib/rhashtable.c:493 [inline]
> rhashtable_try_insert lib/rhashtable.c:661 [inline]
> rhashtable_insert_slow+0x16ab/0x1de0 lib/rhashtable.c:674
> __rhashtable_insert_fast include/linux/rhashtable.h:788 [inline]
> rhashtable_lookup_insert_fast include/linux/rhashtable.h:965 [inline]
> fdb_create+0x13cf/0x1920 net/bridge/br_fdb.c:415
> fdb_add_local net/bridge/br_fdb.c:450 [inline]
> fdb_add_local+0x155/0x1c0 net/bridge/br_fdb.c:430
> br_fdb_add_local+0x39/0x60 net/bridge/br_fdb.c:960
> __vlan_add+0x17f3/0x2e10 net/bridge/br_vlan.c:340
> br_vlan_add+0x2dc/0xa00 net/bridge/br_vlan.c:810
> __vlan_add+0xf7c/0x2e10 net/bridge/br_vlan.c:297
> nbp_vlan_add+0x258/0x3e0 net/bridge/br_vlan.c:1348
> br_vlan_info+0x159/0x3d0 net/bridge/br_netlink.c:705
> br_process_vlan_info+0x404/0x8f0 net/bridge/br_netlink.c:768
> br_afspec+0x422/0x650 net/bridge/br_netlink.c:836
> br_setlink+0x376/0x630 net/bridge/br_netlink.c:1135
> rtnl_bridge_setlink+0x56d/0x740 net/core/rtnetlink.c:5571
> rtnetlink_rcv_msg+0x3c9/0xe90 net/core/rtnetlink.c:7004
> netlink_rcv_skb+0x159/0x420 net/netlink/af_netlink.c:2550
> netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
> netlink_unicast+0x585/0x850 net/netlink/af_netlink.c:1344
> netlink_sendmsg+0x8b0/0xda0 net/netlink/af_netlink.c:1894
> sock_sendmsg_nosec net/socket.c:787 [inline]
> __sock_sendmsg net/socket.c:802 [inline]
> ____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
> ___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
> __sys_sendmsg+0x170/0x220 net/socket.c:2784
> do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
> __do_fast_syscall_32+0xe7/0x950 arch/x86/entry/syscall_32.c:307
> do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332
> entry_SYSENTER_compat_after_hwframe+0x84/0x8e
> RIP: 0023:0xf7f08fcc
> Code: d2 74 05 c1 e8 0c 89 02 8b 5d fc 31 c0 c9 c3 90 90 90 90 90 90 90 90 90
> 90 90 90 90 90 90 0f 1f 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 2e 8d
> b4 26 00 00 00 00 8d b4 26 00 00 00 00 58 b8
> RSP: 002b:00000000f4f6150c EFLAGS: 00000292 ORIG_RAX: 0000000000000172
> RAX: ffffffffffffffda RBX: 000000000000000c RCX: 0000000080000040
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:__get_vm_area_node+0x2d2/0x330 mm/vmalloc.c:3206
> Code: 03 80 3c 11 00 75 5c 48 89 43 08 e9 4b ff ff ff e8 43 a8 a4 ff 48 89 df
> e8 db 98 05 00 31 db e9 37 ff ff ff e8 2f a8 a4 ff 90 <0f> 0b e8 77 6b 11 00
> e9 9e fe ff ff e8 6d 6b 11 00 e9 71 fe ff ff
> RSP: 0018:ffffc90006f76860 EFLAGS: 00010246
> RAX: 0000000000080000 RBX: 0000000000000200 RCX: ffffc90034405000
> RDX: 0000000000080000 RSI: ffffffff82633fb1 RDI: ffff8880244b4a00
> RBP: 000000000000000c R08: 0000000000000005 R09: 0000000000000000
> R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000022
> R13: 0000000000008080 R14: 0000000000000001 R15: 0000000000000000
> FS: 0000000000000000(0000) GS:ffff88809727d000(0063) knlGS:00000000f4f61b40
> CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
> CR2: 00000000f73c4f50 CR3: 0000000055b77000 CR4: 0000000000352ef0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 000000000000000e DR6: 00000000ffff0ff0 DR7: 0000000000000400
> ----------------
> Code disassembly (best guess):
> 0: d2 74 05 c1 shlb %cl,-0x3f(%rbp,%rax,1)
> 4: e8 0c 89 02 8b call 0x8b028915
> 9: 5d pop %rbp
> a: fc cld
> b: 31 c0 xor %eax,%eax
> d: c9 leave
> e: c3 ret
> f: 90 nop
> 10: 90 nop
> 11: 90 nop
> 12: 90 nop
> 13: 90 nop
> 14: 90 nop
> 15: 90 nop
> 16: 90 nop
> 17: 90 nop
> 18: 90 nop
> 19: 90 nop
> 1a: 90 nop
> 1b: 90 nop
> 1c: 90 nop
> 1d: 90 nop
> 1e: 0f 1f 00 nopl (%rax)
> 21: 51 push %rcx
> 22: 52 push %rdx
> 23: 55 push %rbp
> 24: 89 e5 mov %esp,%ebp
> 26: 0f 34 sysenter
> 28: cd 80 int $0x80
> * 2a: 5d pop %rbp <-- trapping instruction
> 2b: 5a pop %rdx
> 2c: 59 pop %rcx
> 2d: c3 ret
> 2e: 90 nop
> 2f: 2e 8d b4 26 00 00 00 cs lea 0x0(%rsi,%riz,1),%esi
> 36: 00
> 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi
> 3e: 58 pop %rax
> 3f: b8 .byte 0xb8
>
>
> ---
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