[v6.1] WARNING in em_cmp_match
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syzbot
Jan 21, 2026, 8:34:28 PM (7 days ago) Jan 21
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: cd9b81672742 Linux 6.1.161
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1168bf9a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b1adc0bfde2d8a4a
dashboard link: https://syzkaller.appspot.com/bug?extid=7cd568ea0d8c6ada6cbe
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d21df4411014/disk-cd9b8167.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/246aed0358fb/vmlinux-cd9b8167.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a6f546504ec2/Image-cd9b8167.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7cd568...@syzkaller.appspotmail.com
device syzkaller0 entered promiscuous mode
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5126 at include/linux/skbuff.h:2844 skb_transport_header include/linux/skbuff.h:2844 [inline]
WARNING: CPU: 1 PID: 5126 at include/linux/skbuff.h:2844 tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
WARNING: CPU: 1 PID: 5126 at include/linux/skbuff.h:2844 em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
Modules linked in:
CPU: 1 PID: 5126 Comm: syz.0.235 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : skb_transport_header include/linux/skbuff.h:2844 [inline]
pc : tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
pc : em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
lr : skb_transport_header include/linux/skbuff.h:2844 [inline]
lr : tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
lr : em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
sp : ffff8000210c6fc0
x29: ffff8000210c6fc0 x28: 0000000000000001 x27: 000000000000ffff
x26: 1fffe0001b0fcfa6 x25: 1fffe0001e5d5f61 x24: dfff800000000000
x23: 000000000000ffff x22: ffff0000d87e7d36 x21: ffff0000f2eafb0a
x20: ffff0000d87e7c80 x19: ffff0000f2eafb00 x18: 0000000000000000
x17: ffff800018338000 x16: ffff8000082eeb30 x15: 0000000000000002
x14: 0000000000000002 x13: 0000000000ff0100 x12: 0000000000080000
x11: 00000000000008b4 x10: ffff800021c4c000 x9 : ffff8000100b822c
x8 : 00000000000008b5 x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000040 x4 : ffffffffffffffe0 x3 : 0000000000000020
x2 : 0000000000000000 x1 : 000000000000ffff x0 : 000000000000ffff
Call trace:
skb_transport_header include/linux/skbuff.h:2844 [inline]
tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
tcf_em_match net/sched/ematch.c:494 [inline]
__tcf_em_tree_match+0x180/0x5e4 net/sched/ematch.c:520
tcf_em_tree_match include/net/pkt_cls.h:502 [inline]
basic_classify+0x138/0x30c net/sched/cls_basic.c:48
__tcf_classify net/sched/cls_api.c:1569 [inline]
tcf_classify+0x1b8/0x9c4 net/sched/cls_api.c:1635
htb_classify net/sched/sch_htb.c:242 [inline]
htb_enqueue+0x2fc/0xf04 net/sched/sch_htb.c:622
dev_qdisc_enqueue+0x5c/0x388 net/core/dev.c:3875
__dev_xmit_skb net/core/dev.c:3964 [inline]
__dev_queue_xmit+0xaf8/0x3134 net/core/dev.c:4312
dev_queue_xmit+0x24/0x34 include/linux/netdevice.h:3051
packet_snd net/packet/af_packet.c:3127 [inline]
packet_sendmsg+0x2f9c/0x3fd0 net/packet/af_packet.c:3158
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
____sys_sendmsg+0x5c8/0x938 net/socket.c:2518
___sys_sendmsg net/socket.c:2572 [inline]
__sys_sendmsg+0x288/0x374 net/socket.c:2601
__do_sys_sendmsg net/socket.c:2610 [inline]
__se_sys_sendmsg net/socket.c:2608 [inline]
__arm64_sys_sendmsg+0x80/0x94 net/socket.c:2608
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 2925
hardirqs last enabled at (2923): [<ffff800011b072cc>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
hardirqs last enabled at (2923): [<ffff800011b072cc>] _raw_spin_unlock_irqrestore+0x48/0xac kernel/locking/spinlock.c:194
hardirqs last disabled at (2925): [<ffff800011a1c234>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last enabled at (2908): [<ffff800008030954>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (2924): [<ffff80000fdc3444>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---
---
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 syzk...@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
syzbot found the following issue on:
HEAD commit: cd9b81672742 Linux 6.1.161
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1168bf9a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=b1adc0bfde2d8a4a
dashboard link: https://syzkaller.appspot.com/bug?extid=7cd568ea0d8c6ada6cbe
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d21df4411014/disk-cd9b8167.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/246aed0358fb/vmlinux-cd9b8167.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a6f546504ec2/Image-cd9b8167.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7cd568...@syzkaller.appspotmail.com
device syzkaller0 entered promiscuous mode
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5126 at include/linux/skbuff.h:2844 skb_transport_header include/linux/skbuff.h:2844 [inline]
WARNING: CPU: 1 PID: 5126 at include/linux/skbuff.h:2844 tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
WARNING: CPU: 1 PID: 5126 at include/linux/skbuff.h:2844 em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
Modules linked in:
CPU: 1 PID: 5126 Comm: syz.0.235 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : skb_transport_header include/linux/skbuff.h:2844 [inline]
pc : tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
pc : em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
lr : skb_transport_header include/linux/skbuff.h:2844 [inline]
lr : tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
lr : em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
sp : ffff8000210c6fc0
x29: ffff8000210c6fc0 x28: 0000000000000001 x27: 000000000000ffff
x26: 1fffe0001b0fcfa6 x25: 1fffe0001e5d5f61 x24: dfff800000000000
x23: 000000000000ffff x22: ffff0000d87e7d36 x21: ffff0000f2eafb0a
x20: ffff0000d87e7c80 x19: ffff0000f2eafb00 x18: 0000000000000000
x17: ffff800018338000 x16: ffff8000082eeb30 x15: 0000000000000002
x14: 0000000000000002 x13: 0000000000ff0100 x12: 0000000000080000
x11: 00000000000008b4 x10: ffff800021c4c000 x9 : ffff8000100b822c
x8 : 00000000000008b5 x7 : 0000000000000000 x6 : 000000000000003f
x5 : 0000000000000040 x4 : ffffffffffffffe0 x3 : 0000000000000020
x2 : 0000000000000000 x1 : 000000000000ffff x0 : 000000000000ffff
Call trace:
skb_transport_header include/linux/skbuff.h:2844 [inline]
tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
tcf_em_match net/sched/ematch.c:494 [inline]
__tcf_em_tree_match+0x180/0x5e4 net/sched/ematch.c:520
tcf_em_tree_match include/net/pkt_cls.h:502 [inline]
basic_classify+0x138/0x30c net/sched/cls_basic.c:48
__tcf_classify net/sched/cls_api.c:1569 [inline]
tcf_classify+0x1b8/0x9c4 net/sched/cls_api.c:1635
htb_classify net/sched/sch_htb.c:242 [inline]
htb_enqueue+0x2fc/0xf04 net/sched/sch_htb.c:622
dev_qdisc_enqueue+0x5c/0x388 net/core/dev.c:3875
__dev_xmit_skb net/core/dev.c:3964 [inline]
__dev_queue_xmit+0xaf8/0x3134 net/core/dev.c:4312
dev_queue_xmit+0x24/0x34 include/linux/netdevice.h:3051
packet_snd net/packet/af_packet.c:3127 [inline]
packet_sendmsg+0x2f9c/0x3fd0 net/packet/af_packet.c:3158
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg net/socket.c:730 [inline]
____sys_sendmsg+0x5c8/0x938 net/socket.c:2518
___sys_sendmsg net/socket.c:2572 [inline]
__sys_sendmsg+0x288/0x374 net/socket.c:2601
__do_sys_sendmsg net/socket.c:2610 [inline]
__se_sys_sendmsg net/socket.c:2608 [inline]
__arm64_sys_sendmsg+0x80/0x94 net/socket.c:2608
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b4 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x130 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
irq event stamp: 2925
hardirqs last enabled at (2923): [<ffff800011b072cc>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
hardirqs last enabled at (2923): [<ffff800011b072cc>] _raw_spin_unlock_irqrestore+0x48/0xac kernel/locking/spinlock.c:194
hardirqs last disabled at (2925): [<ffff800011a1c234>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last enabled at (2908): [<ffff800008030954>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (2924): [<ffff80000fdc3444>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---
---
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 syzk...@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
syzbot
Jan 21, 2026, 10:31:26 PM (7 days ago) Jan 21
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: cd9b81672742 Linux 6.1.161
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=105f1f9a580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13c1f3fa580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d21df4411014/disk-cd9b8167.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/246aed0358fb/vmlinux-cd9b8167.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a6f546504ec2/Image-cd9b8167.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7cd568...@syzkaller.appspotmail.com
device syzkaller0 entered promiscuous mode
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4490 at include/linux/skbuff.h:2844 skb_transport_header include/linux/skbuff.h:2844 [inline]
WARNING: CPU: 1 PID: 4490 at include/linux/skbuff.h:2844 tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
WARNING: CPU: 1 PID: 4490 at include/linux/skbuff.h:2844 em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
Modules linked in:
CPU: 1 PID: 4490 Comm: syz.0.17 Not tainted syzkaller #0
x29: ffff800020bd6fc0 x28: 0000000000000001 x27: 000000000000ffff
x26: 1fffe000199d5066 x25: 1fffe00019c11f21 x24: dfff800000000000
x23: 000000000000ffff x22: ffff0000ccea8336 x21: ffff0000ce08f90a
x20: ffff0000ccea8280 x19: ffff0000ce08f900 x18: 0000000000000000
x17: ffff800018338000 x16: ffff8000082eeb30 x15: 0000000000000000
x14: 0000000000000002 x13: 0000000000ff0100 x12: 0000000000ff0100
x11: ff008000100b822c x10: 0000000000000000 x9 : ffff8000100b822c
x8 : ffff0000d0f69bc0 x7 : 0000000000000000 x6 : 000000000000003f
irq event stamp: 4981
hardirqs last enabled at (4979): [<ffff800011b072cc>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
hardirqs last enabled at (4979): [<ffff800011b072cc>] _raw_spin_unlock_irqrestore+0x48/0xac kernel/locking/spinlock.c:194
hardirqs last disabled at (4981): [<ffff800011a1c234>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last enabled at (4966): [<ffff800008030954>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (4980): [<ffff80000fdc3444>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
HEAD commit: cd9b81672742 Linux 6.1.161
git tree: linux-6.1.y
kernel config: https://syzkaller.appspot.com/x/.config?x=b1adc0bfde2d8a4a
dashboard link: https://syzkaller.appspot.com/bug?extid=7cd568ea0d8c6ada6cbe
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=135bf852580000
dashboard link: https://syzkaller.appspot.com/bug?extid=7cd568ea0d8c6ada6cbe
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
userspace arch: arm64
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13c1f3fa580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d21df4411014/disk-cd9b8167.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/246aed0358fb/vmlinux-cd9b8167.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a6f546504ec2/Image-cd9b8167.gz.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7cd568...@syzkaller.appspotmail.com
device syzkaller0 entered promiscuous mode
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4490 at include/linux/skbuff.h:2844 tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
WARNING: CPU: 1 PID: 4490 at include/linux/skbuff.h:2844 em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
Modules linked in:
CPU: 1 PID: 4490 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : skb_transport_header include/linux/skbuff.h:2844 [inline]
pc : tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
pc : em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
lr : skb_transport_header include/linux/skbuff.h:2844 [inline]
lr : tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
lr : em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
sp : ffff800020bd6fc0
pstate: 82400005 (Nzcv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--)
pc : skb_transport_header include/linux/skbuff.h:2844 [inline]
pc : tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
pc : em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
lr : skb_transport_header include/linux/skbuff.h:2844 [inline]
lr : tcf_get_base_ptr include/net/pkt_cls.h:529 [inline]
lr : em_cmp_match+0x40c/0x5c0 net/sched/em_cmp.c:25
x29: ffff800020bd6fc0 x28: 0000000000000001 x27: 000000000000ffff
x26: 1fffe000199d5066 x25: 1fffe00019c11f21 x24: dfff800000000000
x23: 000000000000ffff x22: ffff0000ccea8336 x21: ffff0000ce08f90a
x20: ffff0000ccea8280 x19: ffff0000ce08f900 x18: 0000000000000000
x17: ffff800018338000 x16: ffff8000082eeb30 x15: 0000000000000000
x14: 0000000000000002 x13: 0000000000ff0100 x12: 0000000000ff0100
x11: ff008000100b822c x10: 0000000000000000 x9 : ffff8000100b822c
x8 : ffff0000d0f69bc0 x7 : 0000000000000000 x6 : 000000000000003f
hardirqs last enabled at (4979): [<ffff800011b072cc>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
hardirqs last enabled at (4979): [<ffff800011b072cc>] _raw_spin_unlock_irqrestore+0x48/0xac kernel/locking/spinlock.c:194
hardirqs last disabled at (4981): [<ffff800011a1c234>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:405
softirqs last enabled at (4966): [<ffff800008030954>] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32
softirqs last disabled at (4980): [<ffff80000fdc3444>] local_bh_disable+0x10/0x34 include/linux/bottom_half.h:19
---[ end trace 0000000000000000 ]---
---
If you want syzbot to run the reproducer, reply with:
---
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.
syzbot
Jan 23, 2026, 12:37:25 AM (6 days ago) Jan 23
to syzkaller...@googlegroups.com
Hello,
syzbot found the following issue on:
HEAD commit: cbb31f77b879 Linux 6.6.121
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11188bfa580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2a950bf7c0bff9f9
dashboard link: https://syzkaller.appspot.com/bug?extid=59da1e47c6e6cb95a53a
disk image: https://storage.googleapis.com/syzbot-assets/6436cbae3604/disk-cbb31f77.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8f3a3d318f99/vmlinux-cbb31f77.xz
kernel image: https://storage.googleapis.com/syzbot-assets/84920a2a012f/bzImage-cbb31f77.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+59da1e...@syzkaller.appspotmail.com
syzkaller0: entered promiscuous mode
syzkaller0: entered allmulticast mode
------------[ cut here ]------------
WARNING: CPU: 0 PID: 16488 at include/linux/skbuff.h:2871 skb_transport_header include/linux/skbuff.h:2871 [inline]
WARNING: CPU: 0 PID: 16488 at include/linux/skbuff.h:2871 tcf_get_base_ptr include/net/pkt_cls.h:528 [inline]
WARNING: CPU: 0 PID: 16488 at include/linux/skbuff.h:2871 em_cmp_match+0x56e/0x7c0 net/sched/em_cmp.c:25
Modules linked in:
CPU: 0 PID: 16488 Comm: syz.5.3213 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:skb_transport_header include/linux/skbuff.h:2871 [inline]
RIP: 0010:tcf_get_base_ptr include/net/pkt_cls.h:528 [inline]
RIP: 0010:em_cmp_match+0x56e/0x7c0 net/sched/em_cmp.c:25
Code: e8 77 b3 d5 f8 39 dd 0f 94 c0 e9 40 fe ff ff e8 e8 b1 d5 f8 e9 34 fe ff ff e8 de b1 d5 f8 0f 0b e9 97 fc ff ff e8 d2 b1 d5 f8 <0f> 0b e9 79 fb ff ff 89 d9 80 e1 07 fe c1 38 c1 0f 8c e5 fa ff ff
RSP: 0018:ffffc900038e70d8 EFLAGS: 00010287
RAX: ffffffff88b1614e RBX: ffff8880318e18ca RCX: 0000000000080000
RDX: ffffc9000d681000 RSI: 0000000000000abd RDI: 0000000000000abe
RBP: 000000000000ffff R08: ffff88807dc41e00 R09: 0000000000000003
R10: 0000000000000002 R11: 0000000000000002 R12: 1ffff1100631c319
R13: 1ffff1100bc3d4b6 R14: ffff88805e1ea500 R15: ffff88805e1ea5b6
FS: 00007fe6c33186c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5eb58706c0 CR3: 0000000077d5f000 CR4: 00000000003526f0
Call Trace:
<TASK>
tcf_em_match net/sched/ematch.c:494 [inline]
__tcf_em_tree_match+0x1cf/0x7a0 net/sched/ematch.c:520
tcf_em_tree_match include/net/pkt_cls.h:501 [inline]
basic_classify+0x115/0x2d0 net/sched/cls_basic.c:50
tc_classify include/net/tc_wrapper.h:227 [inline]
__tcf_classify net/sched/cls_api.c:1704 [inline]
tcf_classify+0x4c4/0xeb0 net/sched/cls_api.c:1788
htb_classify net/sched/sch_htb.c:245 [inline]
htb_enqueue+0x392/0x1260 net/sched/sch_htb.c:625
dev_qdisc_enqueue+0x48/0x220 net/core/dev.c:3850
__dev_xmit_skb net/core/dev.c:3939 [inline]
__dev_queue_xmit+0xea8/0x36b0 net/core/dev.c:4417
packet_snd net/packet/af_packet.c:3137 [inline]
packet_sendmsg+0x3b7a/0x4d70 net/packet/af_packet.c:3169
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x5ba/0x960 net/socket.c:2594
___sys_sendmsg+0x2a6/0x360 net/socket.c:2648
__sys_sendmsg net/socket.c:2677 [inline]
__do_sys_sendmsg net/socket.c:2686 [inline]
__se_sys_sendmsg+0x1c2/0x2b0 net/socket.c:2684
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe6c239acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe6c3318028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe6c2615fa0 RCX: 00007fe6c239acb9
RDX: 0000000000000004 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007fe6c2408bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe6c2616038 R14: 00007fe6c2615fa0 R15: 00007ffe92893ca8
</TASK>
syzbot found the following issue on:
HEAD commit: cbb31f77b879 Linux 6.6.121
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=11188bfa580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2a950bf7c0bff9f9
dashboard link: https://syzkaller.appspot.com/bug?extid=59da1e47c6e6cb95a53a
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6436cbae3604/disk-cbb31f77.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8f3a3d318f99/vmlinux-cbb31f77.xz
kernel image: https://storage.googleapis.com/syzbot-assets/84920a2a012f/bzImage-cbb31f77.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
syzkaller0: entered promiscuous mode
syzkaller0: entered allmulticast mode
------------[ cut here ]------------
WARNING: CPU: 0 PID: 16488 at include/linux/skbuff.h:2871 skb_transport_header include/linux/skbuff.h:2871 [inline]
WARNING: CPU: 0 PID: 16488 at include/linux/skbuff.h:2871 tcf_get_base_ptr include/net/pkt_cls.h:528 [inline]
WARNING: CPU: 0 PID: 16488 at include/linux/skbuff.h:2871 em_cmp_match+0x56e/0x7c0 net/sched/em_cmp.c:25
Modules linked in:
CPU: 0 PID: 16488 Comm: syz.5.3213 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:skb_transport_header include/linux/skbuff.h:2871 [inline]
RIP: 0010:tcf_get_base_ptr include/net/pkt_cls.h:528 [inline]
RIP: 0010:em_cmp_match+0x56e/0x7c0 net/sched/em_cmp.c:25
Code: e8 77 b3 d5 f8 39 dd 0f 94 c0 e9 40 fe ff ff e8 e8 b1 d5 f8 e9 34 fe ff ff e8 de b1 d5 f8 0f 0b e9 97 fc ff ff e8 d2 b1 d5 f8 <0f> 0b e9 79 fb ff ff 89 d9 80 e1 07 fe c1 38 c1 0f 8c e5 fa ff ff
RSP: 0018:ffffc900038e70d8 EFLAGS: 00010287
RAX: ffffffff88b1614e RBX: ffff8880318e18ca RCX: 0000000000080000
RDX: ffffc9000d681000 RSI: 0000000000000abd RDI: 0000000000000abe
RBP: 000000000000ffff R08: ffff88807dc41e00 R09: 0000000000000003
R10: 0000000000000002 R11: 0000000000000002 R12: 1ffff1100631c319
R13: 1ffff1100bc3d4b6 R14: ffff88805e1ea500 R15: ffff88805e1ea5b6
FS: 00007fe6c33186c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5eb58706c0 CR3: 0000000077d5f000 CR4: 00000000003526f0
Call Trace:
<TASK>
tcf_em_match net/sched/ematch.c:494 [inline]
__tcf_em_tree_match+0x1cf/0x7a0 net/sched/ematch.c:520
tcf_em_tree_match include/net/pkt_cls.h:501 [inline]
basic_classify+0x115/0x2d0 net/sched/cls_basic.c:50
tc_classify include/net/tc_wrapper.h:227 [inline]
__tcf_classify net/sched/cls_api.c:1704 [inline]
tcf_classify+0x4c4/0xeb0 net/sched/cls_api.c:1788
htb_classify net/sched/sch_htb.c:245 [inline]
htb_enqueue+0x392/0x1260 net/sched/sch_htb.c:625
dev_qdisc_enqueue+0x48/0x220 net/core/dev.c:3850
__dev_xmit_skb net/core/dev.c:3939 [inline]
__dev_queue_xmit+0xea8/0x36b0 net/core/dev.c:4417
packet_snd net/packet/af_packet.c:3137 [inline]
packet_sendmsg+0x3b7a/0x4d70 net/packet/af_packet.c:3169
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0x5ba/0x960 net/socket.c:2594
___sys_sendmsg+0x2a6/0x360 net/socket.c:2648
__sys_sendmsg net/socket.c:2677 [inline]
__do_sys_sendmsg net/socket.c:2686 [inline]
__se_sys_sendmsg+0x1c2/0x2b0 net/socket.c:2684
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe6c239acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe6c3318028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fe6c2615fa0 RCX: 00007fe6c239acb9
RDX: 0000000000000004 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007fe6c2408bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe6c2616038 R14: 00007fe6c2615fa0 R15: 00007ffe92893ca8
</TASK>
syzbot
Jan 25, 2026, 11:38:29 AM (3 days ago) Jan 25
to syzkaller...@googlegroups.com
syzbot has found a reproducer for the following issue on:
HEAD commit: cbb31f77b879 Linux 6.6.121
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=150cfd22580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1635105a580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6436cbae3604/disk-cbb31f77.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8f3a3d318f99/vmlinux-cbb31f77.xz
kernel image: https://storage.googleapis.com/syzbot-assets/84920a2a012f/bzImage-cbb31f77.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+59da1e...@syzkaller.appspotmail.com
syzkaller0: entered promiscuous mode
syzkaller0: entered allmulticast mode
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5930 at include/linux/skbuff.h:2871 skb_transport_header include/linux/skbuff.h:2871 [inline]
WARNING: CPU: 0 PID: 5930 at include/linux/skbuff.h:2871 tcf_get_base_ptr include/net/pkt_cls.h:528 [inline]
WARNING: CPU: 0 PID: 5930 at include/linux/skbuff.h:2871 em_cmp_match+0x56e/0x7c0 net/sched/em_cmp.c:25
Modules linked in:
CPU: 0 PID: 5930 Comm: syz.0.17 Not tainted syzkaller #0
RAX: ffffffff88b1614e RBX: ffff8880240a736a RCX: ffff88802bc8bc00
RDX: 0000000000000000 RSI: 000000000000ffff RDI: 000000000000ffff
RBP: 000000000000ffff R08: ffff88802bc8bc00 R09: 0000000000000003
R10: 0000000000000002 R11: 0000000000000000 R12: 1ffff11004814e6d
R13: 1ffff110039fd416 R14: ffff88801cfea000 R15: ffff88801cfea0b6
FS: 0000555588f44500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
RIP: 0033:0x7f8fed59acb9
RAX: ffffffffffffffda RBX: 00007f8fed815fa0 RCX: 00007f8fed59acb9
</TASK>
HEAD commit: cbb31f77b879 Linux 6.6.121
git tree: linux-6.6.y
kernel config: https://syzkaller.appspot.com/x/.config?x=2a950bf7c0bff9f9
dashboard link: https://syzkaller.appspot.com/bug?extid=59da1e47c6e6cb95a53a
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12c3c05a580000
dashboard link: https://syzkaller.appspot.com/bug?extid=59da1e47c6e6cb95a53a
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1635105a580000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6436cbae3604/disk-cbb31f77.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8f3a3d318f99/vmlinux-cbb31f77.xz
kernel image: https://storage.googleapis.com/syzbot-assets/84920a2a012f/bzImage-cbb31f77.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+59da1e...@syzkaller.appspotmail.com
syzkaller0: entered promiscuous mode
syzkaller0: entered allmulticast mode
------------[ cut here ]------------
WARNING: CPU: 0 PID: 5930 at include/linux/skbuff.h:2871 tcf_get_base_ptr include/net/pkt_cls.h:528 [inline]
WARNING: CPU: 0 PID: 5930 at include/linux/skbuff.h:2871 em_cmp_match+0x56e/0x7c0 net/sched/em_cmp.c:25
Modules linked in:
CPU: 0 PID: 5930 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:skb_transport_header include/linux/skbuff.h:2871 [inline]
RIP: 0010:tcf_get_base_ptr include/net/pkt_cls.h:528 [inline]
RIP: 0010:em_cmp_match+0x56e/0x7c0 net/sched/em_cmp.c:25
Code: e8 77 b3 d5 f8 39 dd 0f 94 c0 e9 40 fe ff ff e8 e8 b1 d5 f8 e9 34 fe ff ff e8 de b1 d5 f8 0f 0b e9 97 fc ff ff e8 d2 b1 d5 f8 <0f> 0b e9 79 fb ff ff 89 d9 80 e1 07 fe c1 38 c1 0f 8c e5 fa ff ff
RSP: 0018:ffffc900032e70d8 EFLAGS: 00010293
RIP: 0010:skb_transport_header include/linux/skbuff.h:2871 [inline]
RIP: 0010:tcf_get_base_ptr include/net/pkt_cls.h:528 [inline]
RIP: 0010:em_cmp_match+0x56e/0x7c0 net/sched/em_cmp.c:25
Code: e8 77 b3 d5 f8 39 dd 0f 94 c0 e9 40 fe ff ff e8 e8 b1 d5 f8 e9 34 fe ff ff e8 de b1 d5 f8 0f 0b e9 97 fc ff ff e8 d2 b1 d5 f8 <0f> 0b e9 79 fb ff ff 89 d9 80 e1 07 fe c1 38 c1 0f 8c e5 fa ff ff
RAX: ffffffff88b1614e RBX: ffff8880240a736a RCX: ffff88802bc8bc00
RDX: 0000000000000000 RSI: 000000000000ffff RDI: 000000000000ffff
RBP: 000000000000ffff R08: ffff88802bc8bc00 R09: 0000000000000003
R10: 0000000000000002 R11: 0000000000000000 R12: 1ffff11004814e6d
R13: 1ffff110039fd416 R14: ffff88801cfea000 R15: ffff88801cfea0b6
FS: 0000555588f44500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002280 CR3: 000000002dfd5000 CR4: 00000000003506f0
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffee36a6d68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8fed815fa0 RCX: 00007f8fed59acb9
RDX: 0000000000000004 RSI: 00002000000000c0 RDI: 0000000000000005
RBP: 00007f8fed608bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8fed815fac R14: 00007f8fed815fa0 R15: 00007f8fed815fa0
</TASK>
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