* [syzbot] [bridge?] kernel BUG in __get_vm_area_node
@ 2026-05-09 19:35 syzbot
2026-05-12 8:47 ` Ido Schimmel
0 siblings, 1 reply; 4+ messages in thread
From: syzbot @ 2026-05-09 19:35 UTC (permalink / raw)
To: bridge, davem, edumazet, horms, idosch, kuba, linux-kernel,
netdev, pabeni, razor, syzkaller-bugs
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: syzbot+8b12fc6e0fb139765b58@syzkaller.appspotmail.com
------------[ cut here ]------------
kernel BUG at mm/vmalloc.c:3206!
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
---
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:
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(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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] [bridge?] kernel BUG in __get_vm_area_node
2026-05-09 19:35 [syzbot] [bridge?] kernel BUG in __get_vm_area_node syzbot
@ 2026-05-12 8:47 ` Ido Schimmel
2026-05-12 9:26 ` Uladzislau Rezki
0 siblings, 1 reply; 4+ messages in thread
From: Ido Schimmel @ 2026-05-12 8:47 UTC (permalink / raw)
To: syzbot, urezki
Cc: bridge, davem, edumazet, horms, kuba, linux-kernel, netdev,
pabeni, razor, syzkaller-bugs, fw
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: syzbot+8b12fc6e0fb139765b58@syzkaller.appspotmail.com
>
> ------------[ 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
>
>
> ---
> 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
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [syzbot] [bridge?] kernel BUG in __get_vm_area_node
2026-05-12 8:47 ` Ido Schimmel
@ 2026-05-12 9:26 ` Uladzislau Rezki
2026-05-12 13:17 ` Uladzislau Rezki
0 siblings, 1 reply; 4+ messages in thread
From: Uladzislau Rezki @ 2026-05-12 9:26 UTC (permalink / raw)
To: Ido Schimmel
Cc: syzbot, urezki, bridge, davem, edumazet, horms, kuba,
linux-kernel, netdev, pabeni, razor, syzkaller-bugs, fw
On Tue, May 12, 2026 at 11:47:54AM +0300, Ido Schimmel wrote:
> 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: syzbot+8b12fc6e0fb139765b58@syzkaller.appspotmail.com
> >
> > ------------[ 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.
>
Yep, since vmalloc can be called with ATOMIC/NOWAIT flags now. I am
checking this. Probably we can just remove below check:
<snip>
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 676851d5cfe7..3d338e4bcbf7 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3209,7 +3209,6 @@ struct vm_struct *__get_vm_area_node(unsigned long size,
struct vm_struct *area;
unsigned long requested_size = size;
- BUG_ON(in_interrupt());
size = ALIGN(size, 1ul << shift);
if (unlikely(!size))
return NULL;
<snip>
We have already the check:
gfp_mask = gfp_mask & GFP_RECLAIM_MASK;
allow_block = gfpflags_allow_blocking(gfp_mask);
might_sleep_if(allow_block);
in alloc_vmap_area().
--
Uladzislau Rezki
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [syzbot] [bridge?] kernel BUG in __get_vm_area_node
2026-05-12 9:26 ` Uladzislau Rezki
@ 2026-05-12 13:17 ` Uladzislau Rezki
0 siblings, 0 replies; 4+ messages in thread
From: Uladzislau Rezki @ 2026-05-12 13:17 UTC (permalink / raw)
To: Ido Schimmel
Cc: Ido Schimmel, syzbot, bridge, davem, edumazet, horms, kuba,
linux-kernel, netdev, pabeni, razor, syzkaller-bugs, fw
On Tue, May 12, 2026 at 11:26:06AM +0200, Uladzislau Rezki wrote:
> On Tue, May 12, 2026 at 11:47:54AM +0300, Ido Schimmel wrote:
> > 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: syzbot+8b12fc6e0fb139765b58@syzkaller.appspotmail.com
> > >
> > > ------------[ 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.
> >
> Yep, since vmalloc can be called with ATOMIC/NOWAIT flags now. I am
> checking this. Probably we can just remove below check:
>
> <snip>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 676851d5cfe7..3d338e4bcbf7 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -3209,7 +3209,6 @@ struct vm_struct *__get_vm_area_node(unsigned long size,
> struct vm_struct *area;
> unsigned long requested_size = size;
>
> - BUG_ON(in_interrupt());
> size = ALIGN(size, 1ul << shift);
> if (unlikely(!size))
> return NULL;
> <snip>
>
> We have already the check:
>
> gfp_mask = gfp_mask & GFP_RECLAIM_MASK;
> allow_block = gfpflags_allow_blocking(gfp_mask);
> might_sleep_if(allow_block);
>
> in alloc_vmap_area().
>
Actually since we are not allowed to call vmalloc from NMI nor IRQ
context. We should keep the check. But in a slightly different form:
<snip>
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 676851d5cfe7..273bbe49eaef 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3209,7 +3209,7 @@ struct vm_struct *__get_vm_area_node(unsigned long size,
struct vm_struct *area;
unsigned long requested_size = size;
- BUG_ON(in_interrupt());
+ BUG_ON(in_nmi() || in_hardirq());
size = ALIGN(size, 1ul << shift);
if (unlikely(!size))
return NULL;
<snip>
if any context disables BH, i.e. local_bh_disable() it does not mean we
are in IRQ context. Furthermore the documentation about in_interrupt()
says:
<snip>
/*
* The following macros are deprecated and should not be used in new code:
* in_softirq() - We have BH disabled, or are processing softirqs
* in_interrupt() - We're in NMI,IRQ,SoftIRQ context or have BH disabled
*/
#define in_softirq() (softirq_count())
#define in_interrupt() (irq_count())
<snip>
those are should not be used.
--
Uladzislau Rezki
^ permalink raw reply related [flat|nested] 4+ messages in thread
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2026-05-09 19:35 [syzbot] [bridge?] kernel BUG in __get_vm_area_node syzbot
2026-05-12 8:47 ` Ido Schimmel
2026-05-12 9:26 ` Uladzislau Rezki
2026-05-12 13:17 ` Uladzislau Rezki
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