[v6.6] BUG: assuming non migratable context at include/linux/filter.h:LINE

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9247f4e6573a Linux 6.6.98
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13ab8382580000
kernel config: https://syzkaller.appspot.com/x/.config?x=cfe840f14e117c98
dashboard link: https://syzkaller.appspot.com/bug?extid=2a814821d13380314b07
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3855f6db0ca8/disk-9247f4e6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fe3d6afeb3a6/vmlinux-9247f4e6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7d8784621ac6/bzImage-9247f4e6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2a8148...@syzkaller.appspotmail.com

BUG: assuming non migratable context at include/linux/filter.h:599
in_atomic(): 0, irqs_disabled(): 0, migration_disabled() 0 pid: 20971, name: syz.4.4340
1 lock held by syz.4.4340/20971:
#0: ffffffff8cd2fae0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8cd2fae0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8cd2fae0 (rcu_read_lock){....}-{1:2}, at: nf_hook+0x9e/0x370 include/linux/netfilter.h:228
CPU: 1 PID: 20971 Comm: syz.4.4340 Not tainted 6.6.98-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
__cant_migrate+0x234/0x2e0 kernel/sched/core.c:10269
__bpf_prog_run include/linux/filter.h:599 [inline]
bpf_prog_run include/linux/filter.h:619 [inline]
nf_hook_run_bpf+0x90/0x1e0 net/netfilter/nf_bpf_link.c:20
nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline]
nf_hook_slow+0xbd/0x200 net/netfilter/core.c:626
nf_hook+0x215/0x370 include/linux/netfilter.h:259
NF_HOOK_COND include/linux/netfilter.h:292 [inline]
ip_output+0x16c/0x210 net/ipv4/ip_output.c:433
dst_output include/net/dst.h:467 [inline]
ip_local_out net/ipv4/ip_output.c:129 [inline]
ip_send_skb+0x12d/0x1d0 net/ipv4/ip_output.c:1491
udp_send_skb+0xa37/0x13a0 net/ipv4/udp.c:984
udp_sendmsg+0x19b8/0x2330 net/ipv4/udp.c:1270
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
__sys_sendto+0x46a/0x620 net/socket.c:2201
__do_sys_sendto net/socket.c:2213 [inline]
__se_sys_sendto net/socket.c:2209 [inline]
__x64_sys_sendto+0xde/0xf0 net/socket.c:2209
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f1caa98e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1cab8bb038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f1caabb5fa0 RCX: 00007f1caa98e929
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 00007f1caaa10b39 R08: 0000200000000000 R09: 0000000000000010
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f1caabb5fa0 R15: 00007ffe69128ee8
</TASK>


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 9247f4e6573a Linux 6.6.98
git tree: linux-6.6.y

console output: https://syzkaller.appspot.com/x/log.txt?x=16514382580000

kernel config: https://syzkaller.appspot.com/x/.config?x=cfe840f14e117c98
dashboard link: https://syzkaller.appspot.com/bug?extid=2a814821d13380314b07
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11514382580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10e327d4580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3855f6db0ca8/disk-9247f4e6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fe3d6afeb3a6/vmlinux-9247f4e6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7d8784621ac6/bzImage-9247f4e6.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2a8148...@syzkaller.appspotmail.com

BUG: assuming non migratable context at include/linux/filter.h:599

in_atomic(): 0, irqs_disabled(): 0, migration_disabled() 0 pid: 5937, name: syz.0.16
1 lock held by syz.0.16/5937:

#0: ffffffff8cd2fae0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
#0: ffffffff8cd2fae0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:786 [inline]
#0: ffffffff8cd2fae0 (rcu_read_lock){....}-{1:2}, at: nf_hook+0x9e/0x370 include/linux/netfilter.h:228

CPU: 0 PID: 5937 Comm: syz.0.16 Not tainted 6.6.98-syzkaller #0

RIP: 0033:0x7f5aed78e929

Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007ffe20dc60f8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f5aed9b5fa0 RCX: 00007f5aed78e929

RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005

RBP: 00007f5aed810b39 R08: 0000200000000000 R09: 0000000000000010

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007f5aed9b5fa0 R14: 00007f5aed9b5fa0 R15: 0000000000000006
</TASK>


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
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[syzbot]

syzbot suspects this issue was fixed by commit:

commit ee2502485702e4398cd74dbfb288bfa111d25e62
Author: Kuniyuki Iwashima <kun...@google.com>
Date: Tue Jul 22 22:40:37 2025 +0000

bpf: Disable migration in nf_hook_run_bpf().

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17ff6534580000
start commit: 3a8ababb8b6a Linux 6.6.101
git tree: linux-6.6.y
kernel config: https://syzkaller.appspot.com/x/.config?x=a2bd95b6de4839b7
dashboard link: https://syzkaller.appspot.com/bug?extid=2a814821d13380314b07
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=144c65a2580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16151842580000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: bpf: Disable migration in nf_hook_run_bpf().

For information about bisection process see: https://goo.gl/tpsmEJ#bisection