Hello,
syzbot hit the following crash on
https://github.com/google/kmsan.git/master commit
e2ab7e8abba47a2f2698216258e5d8727ae58717 (Fri Apr 6 16:24:31 2018 +0000)
kmsan: temporarily disable visitAsmInstruction() to help syzbot
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=b202b7208664142954fa
Unfortunately, I don't have any reproducer for this crash yet.
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=5356516437655552
Kernel config:
https://syzkaller.appspot.com/x/.config?id=6627248707860932248
compiler: clang version 7.0.0 (trunk 329391)
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]
It will help syzbot understand when the bug is fixed. See footer for
details.
If you forward the report, please keep this part and the footer.
==================================================================
BUG: KMSAN: uninit-value in __read_once_size include/linux/compiler.h:197
[inline]
BUG: KMSAN: uninit-value in deliver_ptype_list_skb net/core/dev.c:1908
[inline]
BUG: KMSAN: uninit-value in __netif_receive_skb_core+0x4630/0x4a80
net/core/dev.c:4545
CPU: 0 PID: 5999 Comm: syz-executor3 Not tainted 4.16.0+ #82
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x185/0x1d0 lib/dump_stack.c:53
kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
__msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
__read_once_size include/linux/compiler.h:197 [inline]
deliver_ptype_list_skb net/core/dev.c:1908 [inline]
__netif_receive_skb_core+0x4630/0x4a80 net/core/dev.c:4545
__netif_receive_skb net/core/dev.c:4627 [inline]
process_backlog+0x62d/0xe20 net/core/dev.c:5307
napi_poll net/core/dev.c:5705 [inline]
net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
__do_softirq+0x56d/0x93d kernel/softirq.c:285
do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1040
</IRQ>
do_softirq kernel/softirq.c:329 [inline]
__local_bh_enable_ip+0x114/0x140 kernel/softirq.c:182
local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
rcu_read_unlock_bh include/linux/rcupdate.h:726 [inline]
__dev_queue_xmit+0x2a31/0x2b60 net/core/dev.c:3584
dev_queue_xmit+0x4b/0x60 net/core/dev.c:3590
packet_snd net/packet/af_packet.c:2944 [inline]
packet_sendmsg+0x7c57/0x8a10 net/packet/af_packet.c:2969
sock_sendmsg_nosec net/socket.c:630 [inline]
sock_sendmsg net/socket.c:640 [inline]
sock_write_iter+0x3b9/0x470 net/socket.c:909
do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776
do_iter_write+0x30d/0xd40 fs/read_write.c:932
vfs_writev fs/read_write.c:977 [inline]
do_writev+0x3c9/0x830 fs/read_write.c:1012
SYSC_writev+0x9b/0xb0 fs/read_write.c:1085
SyS_writev+0x56/0x80 fs/read_write.c:1082
do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455259
RSP: 002b:00007fb53ede8c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007fb53ede96d4 RCX: 0000000000455259
RDX: 0000000000000001 RSI: 00000000200010c0 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000006cd R14: 00000000006fd3d8 R15: 0000000000000000
Uninit was stored to memory at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
__msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:521
skb_vlan_untag+0x950/0xee0 include/linux/if_vlan.h:597
__netif_receive_skb_core+0x70a/0x4a80 net/core/dev.c:4460
__netif_receive_skb net/core/dev.c:4627 [inline]
process_backlog+0x62d/0xe20 net/core/dev.c:5307
napi_poll net/core/dev.c:5705 [inline]
net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
__do_softirq+0x56d/0x93d kernel/softirq.c:285
Uninit was created at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
slab_post_alloc_hook mm/slab.h:445 [inline]
slab_alloc_node mm/slub.c:2737 [inline]
__kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
__kmalloc_reserve net/core/skbuff.c:138 [inline]
__alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
alloc_skb include/linux/skbuff.h:984 [inline]
alloc_skb_with_frags+0x1d4/0xb20 net/core/skbuff.c:5234
sock_alloc_send_pskb+0xb56/0x1190 net/core/sock.c:2085
packet_alloc_skb net/packet/af_packet.c:2803 [inline]
packet_snd net/packet/af_packet.c:2894 [inline]
packet_sendmsg+0x6444/0x8a10 net/packet/af_packet.c:2969
sock_sendmsg_nosec net/socket.c:630 [inline]
sock_sendmsg net/socket.c:640 [inline]
sock_write_iter+0x3b9/0x470 net/socket.c:909
do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776
do_iter_write+0x30d/0xd40 fs/read_write.c:932
vfs_writev fs/read_write.c:977 [inline]
do_writev+0x3c9/0x830 fs/read_write.c:1012
SYSC_writev+0x9b/0xb0 fs/read_write.c:1085
SyS_writev+0x56/0x80 fs/read_write.c:1082
do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
==================================================================
---
This bug is generated by a dumb bot. It may contain errors.
See https://goo.gl/tpsmEJ for details.
Direct all questions to [email protected].
syzbot will keep track of this bug report.
If you forgot to add the Reported-by tag, once the fix for this bug is
merged
into any tree, please reply to this email with:
#syz fix: exact-commit-title
To mark this as a duplicate of another syzbot report, please reply with:
#syz dup: exact-subject-of-another-report
If it's a one-off invalid bug report, please reply with:
#syz invalid
Note: if the crash happens again, it will cause creation of a new bug
report.
Note: all commands must start from beginning of the line in the email body.
On Thu, Apr 12, 2018 at 10:01 AM, syzbot
<[email protected]> wrote:
> Hello,
>
> syzbot hit the following crash on https://github.com/google/kmsan.git/master
> commit
> e2ab7e8abba47a2f2698216258e5d8727ae58717 (Fri Apr 6 16:24:31 2018 +0000)
> kmsan: temporarily disable visitAsmInstruction() to help syzbot
> syzbot dashboard link:
> https://syzkaller.appspot.com/bug?extid=b202b7208664142954fa
>
> Unfortunately, I don't have any reproducer for this crash yet.
> Raw console output:
> https://syzkaller.appspot.com/x/log.txt?id=5356516437655552
> Kernel config:
> https://syzkaller.appspot.com/x/.config?id=6627248707860932248
> compiler: clang version 7.0.0 (trunk 329391)
+Toshiaki as this seems to be related to the recent vlan tagging changes.
This also seems to be related to
https://groups.google.com/d/msg/syzkaller-bugs/VRH9NnUi2k0/90GYsAeRBgAJ
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: [email protected]
> It will help syzbot understand when the bug is fixed. See footer for
> details.
> If you forward the report, please keep this part and the footer.
>
> ==================================================================
> BUG: KMSAN: uninit-value in __read_once_size include/linux/compiler.h:197
> [inline]
> BUG: KMSAN: uninit-value in deliver_ptype_list_skb net/core/dev.c:1908
> [inline]
> BUG: KMSAN: uninit-value in __netif_receive_skb_core+0x4630/0x4a80
> net/core/dev.c:4545
> CPU: 0 PID: 5999 Comm: syz-executor3 Not tainted 4.16.0+ #82
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
> Google 01/01/2011
> Call Trace:
> <IRQ>
> __dump_stack lib/dump_stack.c:17 [inline]
> dump_stack+0x185/0x1d0 lib/dump_stack.c:53
> kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
> __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
> __read_once_size include/linux/compiler.h:197 [inline]
> deliver_ptype_list_skb net/core/dev.c:1908 [inline]
> __netif_receive_skb_core+0x4630/0x4a80 net/core/dev.c:4545
> __netif_receive_skb net/core/dev.c:4627 [inline]
> process_backlog+0x62d/0xe20 net/core/dev.c:5307
> napi_poll net/core/dev.c:5705 [inline]
> net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
> __do_softirq+0x56d/0x93d kernel/softirq.c:285
> do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1040
> </IRQ>
> do_softirq kernel/softirq.c:329 [inline]
> __local_bh_enable_ip+0x114/0x140 kernel/softirq.c:182
> local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
> rcu_read_unlock_bh include/linux/rcupdate.h:726 [inline]
> __dev_queue_xmit+0x2a31/0x2b60 net/core/dev.c:3584
> dev_queue_xmit+0x4b/0x60 net/core/dev.c:3590
> packet_snd net/packet/af_packet.c:2944 [inline]
> packet_sendmsg+0x7c57/0x8a10 net/packet/af_packet.c:2969
> sock_sendmsg_nosec net/socket.c:630 [inline]
> sock_sendmsg net/socket.c:640 [inline]
> sock_write_iter+0x3b9/0x470 net/socket.c:909
> do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776
> do_iter_write+0x30d/0xd40 fs/read_write.c:932
> vfs_writev fs/read_write.c:977 [inline]
> do_writev+0x3c9/0x830 fs/read_write.c:1012
> SYSC_writev+0x9b/0xb0 fs/read_write.c:1085
> SyS_writev+0x56/0x80 fs/read_write.c:1082
> do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
> entry_SYSCALL_64_after_hwframe+0x3d/0xa2
> RIP: 0033:0x455259
> RSP: 002b:00007fb53ede8c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
> RAX: ffffffffffffffda RBX: 00007fb53ede96d4 RCX: 0000000000455259
> RDX: 0000000000000001 RSI: 00000000200010c0 RDI: 0000000000000013
> RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
> R13: 00000000000006cd R14: 00000000006fd3d8 R15: 0000000000000000
>
> Uninit was stored to memory at:
> kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
> kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
> kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
> __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:521
> skb_vlan_untag+0x950/0xee0 include/linux/if_vlan.h:597
> __netif_receive_skb_core+0x70a/0x4a80 net/core/dev.c:4460
> __netif_receive_skb net/core/dev.c:4627 [inline]
> process_backlog+0x62d/0xe20 net/core/dev.c:5307
> napi_poll net/core/dev.c:5705 [inline]
> net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
> __do_softirq+0x56d/0x93d kernel/softirq.c:285
> Uninit was created at:
> kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
> kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
> kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
> kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
> slab_post_alloc_hook mm/slab.h:445 [inline]
> slab_alloc_node mm/slub.c:2737 [inline]
> __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
> __kmalloc_reserve net/core/skbuff.c:138 [inline]
> __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
> alloc_skb include/linux/skbuff.h:984 [inline]
> alloc_skb_with_frags+0x1d4/0xb20 net/core/skbuff.c:5234
> sock_alloc_send_pskb+0xb56/0x1190 net/core/sock.c:2085
> packet_alloc_skb net/packet/af_packet.c:2803 [inline]
> packet_snd net/packet/af_packet.c:2894 [inline]
> packet_sendmsg+0x6444/0x8a10 net/packet/af_packet.c:2969
> sock_sendmsg_nosec net/socket.c:630 [inline]
> sock_sendmsg net/socket.c:640 [inline]
> sock_write_iter+0x3b9/0x470 net/socket.c:909
> do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776
> do_iter_write+0x30d/0xd40 fs/read_write.c:932
> vfs_writev fs/read_write.c:977 [inline]
> do_writev+0x3c9/0x830 fs/read_write.c:1012
> SYSC_writev+0x9b/0xb0 fs/read_write.c:1085
> SyS_writev+0x56/0x80 fs/read_write.c:1082
> do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
> entry_SYSCALL_64_after_hwframe+0x3d/0xa2
> ==================================================================
>
>
> ---
> This bug is generated by a dumb bot. It may contain errors.
> See https://goo.gl/tpsmEJ for details.
> Direct all questions to [email protected].
>
> syzbot will keep track of this bug report.
> If you forgot to add the Reported-by tag, once the fix for this bug is
> merged
> into any tree, please reply to this email with:
> #syz fix: exact-commit-title
> To mark this as a duplicate of another syzbot report, please reply with:
> #syz dup: exact-subject-of-another-report
> If it's a one-off invalid bug report, please reply with:
> #syz invalid
> Note: if the crash happens again, it will cause creation of a new bug
> report.
> Note: all commands must start from beginning of the line in the email body.
>
> --
> You received this message because you are subscribed to the Google Groups
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> To view this discussion on the web visit
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> For more options, visit https://groups.google.com/d/optout.
syzbot has found reproducer for the following crash on
https://github.com/google/kmsan.git/master commit
35ff515e4bda2646f6c881d33951c306ea9c282a (Tue Apr 10 08:59:43 2018 +0000)
Merge pull request #11 from parkerduckworth/readme
syzbot dashboard link:
https://syzkaller.appspot.com/bug?extid=b202b7208664142954fa
So far this crash happened 3 times on
https://github.com/google/kmsan.git/master.
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=4559916236800000
syzkaller reproducer:
https://syzkaller.appspot.com/x/repro.syz?id=4590273065648128
Raw console output:
https://syzkaller.appspot.com/x/log.txt?id=4631921027973120
Kernel config:
https://syzkaller.appspot.com/x/.config?id=6627248707860932248
compiler: clang version 7.0.0 (trunk 329391)
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email protected]
It will help syzbot understand when the bug is fixed.
==================================================================
BUG: KMSAN: uninit-value in __read_once_size include/linux/compiler.h:197
[inline]
BUG: KMSAN: uninit-value in deliver_ptype_list_skb net/core/dev.c:1908
[inline]
BUG: KMSAN: uninit-value in __netif_receive_skb_core+0x4630/0x4a80
net/core/dev.c:4545
CPU: 0 PID: 3514 Comm: syzkaller031167 Not tainted 4.16.0+ #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x185/0x1d0 lib/dump_stack.c:53
kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
__msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
__read_once_size include/linux/compiler.h:197 [inline]
deliver_ptype_list_skb net/core/dev.c:1908 [inline]
__netif_receive_skb_core+0x4630/0x4a80 net/core/dev.c:4545
__netif_receive_skb net/core/dev.c:4627 [inline]
process_backlog+0x62d/0xe20 net/core/dev.c:5307
napi_poll net/core/dev.c:5705 [inline]
net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
__do_softirq+0x56d/0x93d kernel/softirq.c:285
do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1040
</IRQ>
do_softirq kernel/softirq.c:329 [inline]
__local_bh_enable_ip+0x114/0x140 kernel/softirq.c:182
local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
rcu_read_unlock_bh include/linux/rcupdate.h:726 [inline]
__dev_queue_xmit+0x2a31/0x2b60 net/core/dev.c:3584
dev_queue_xmit+0x4b/0x60 net/core/dev.c:3590
packet_snd net/packet/af_packet.c:2944 [inline]
packet_sendmsg+0x7c57/0x8a10 net/packet/af_packet.c:2969
sock_sendmsg_nosec net/socket.c:630 [inline]
sock_sendmsg net/socket.c:640 [inline]
sock_write_iter+0x3b9/0x470 net/socket.c:909
do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776
do_iter_write+0x30d/0xd40 fs/read_write.c:932
vfs_writev fs/read_write.c:977 [inline]
do_writev+0x3c9/0x830 fs/read_write.c:1012
SYSC_writev+0x9b/0xb0 fs/read_write.c:1085
SyS_writev+0x56/0x80 fs/read_write.c:1082
do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x43ffb9
RSP: 002b:00007ffd42187708 EFLAGS: 00000217 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043ffb9
RDX: 0000000000000001 RSI: 00000000200010c0 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000217 R12: 00000000004018e0
R13: 0000000000401970 R14: 0000000000000000 R15: 0000000000000000
Uninit was stored to memory at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
__msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:521
skb_vlan_untag+0x950/0xee0 include/linux/if_vlan.h:597
__netif_receive_skb_core+0x70a/0x4a80 net/core/dev.c:4460
__netif_receive_skb net/core/dev.c:4627 [inline]
process_backlog+0x62d/0xe20 net/core/dev.c:5307
napi_poll net/core/dev.c:5705 [inline]
net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
__do_softirq+0x56d/0x93d kernel/softirq.c:285
Uninit was created at:
kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
slab_post_alloc_hook mm/slab.h:445 [inline]
slab_alloc_node mm/slub.c:2737 [inline]
__kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
__kmalloc_reserve net/core/skbuff.c:138 [inline]
__alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
alloc_skb include/linux/skbuff.h:984 [inline]
alloc_skb_with_frags+0x1d4/0xb20 net/core/skbuff.c:5234
sock_alloc_send_pskb+0xb56/0x1190 net/core/sock.c:2085
packet_alloc_skb net/packet/af_packet.c:2803 [inline]
packet_snd net/packet/af_packet.c:2894 [inline]
packet_sendmsg+0x6444/0x8a10 net/packet/af_packet.c:2969
sock_sendmsg_nosec net/socket.c:630 [inline]
sock_sendmsg net/socket.c:640 [inline]
sock_write_iter+0x3b9/0x470 net/socket.c:909
do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776
do_iter_write+0x30d/0xd40 fs/read_write.c:932
vfs_writev fs/read_write.c:977 [inline]
do_writev+0x3c9/0x830 fs/read_write.c:1012
SYSC_writev+0x9b/0xb0 fs/read_write.c:1085
SyS_writev+0x56/0x80 fs/read_write.c:1082
do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
==================================================================
On Fri, Apr 13, 2018 at 10:20 AM, Toshiaki Makita
<[email protected]> wrote:
> On 2018/04/12 17:03, Dmitry Vyukov wrote:
>> On Thu, Apr 12, 2018 at 10:01 AM, syzbot
>> <[email protected]> wrote:
>>> Hello,
>>>
>>> syzbot hit the following crash on https://github.com/google/kmsan.git/master
>>> commit
>>> e2ab7e8abba47a2f2698216258e5d8727ae58717 (Fri Apr 6 16:24:31 2018 +0000)
>>> kmsan: temporarily disable visitAsmInstruction() to help syzbot
>>> syzbot dashboard link:
>>> https://syzkaller.appspot.com/bug?extid=b202b7208664142954fa
>>>
>>> Unfortunately, I don't have any reproducer for this crash yet.
>>> Raw console output:
>>> https://syzkaller.appspot.com/x/log.txt?id=5356516437655552
>>> Kernel config:
>>> https://syzkaller.appspot.com/x/.config?id=6627248707860932248
>>> compiler: clang version 7.0.0 (trunk 329391)
>>
>> +Toshiaki as this seems to be related to the recent vlan tagging changes.
>
> seems not...
> "Uninit was stored to memory at:" shows uninitialized memory was stored
> before where I modified the code (skb_reorder_vlan_header).
>
> I'm not sure what this uninit memory means.
> To me it looks like the memory is initialized by user provided data.
>
> (iov in packet sock -> skb->data -> skb->protocol)
>
> The reproducer provides 4 bytes after ethernet header, so it should be
> sufficient for a vlan tag. This will set skb->len to 4 and fill the
> 4-byte contents in packet_snd(). skb_vlan_untag() is reading the user
> provided 4-byte skb->data. It is ensured that skb_vlan_untag() does not
> read beyond skb->len since it calls pskb_may_pull(). At this point I am
> failing to find what I am missing.
Eric,
You mentioned something about assumption that the
__vlan_insert_inner_tag() helper would only be called from
__netif_receive_skb_core(). Can you elaborate?
>> This also seems to be related to
>> https://groups.google.com/d/msg/syzkaller-bugs/VRH9NnUi2k0/90GYsAeRBgAJ
>>
>>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>>> Reported-by: [email protected]
>>> It will help syzbot understand when the bug is fixed. See footer for
>>> details.
>>> If you forward the report, please keep this part and the footer.
>>>
>>> ==================================================================
>>> BUG: KMSAN: uninit-value in __read_once_size include/linux/compiler.h:197
>>> [inline]
>>> BUG: KMSAN: uninit-value in deliver_ptype_list_skb net/core/dev.c:1908
>>> [inline]
>>> BUG: KMSAN: uninit-value in __netif_receive_skb_core+0x4630/0x4a80
>>> net/core/dev.c:4545
>>> CPU: 0 PID: 5999 Comm: syz-executor3 Not tainted 4.16.0+ #82
>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>>> Google 01/01/2011
>>> Call Trace:
>>> <IRQ>
>>> __dump_stack lib/dump_stack.c:17 [inline]
>>> dump_stack+0x185/0x1d0 lib/dump_stack.c:53
>>> kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
>>> __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
>>> __read_once_size include/linux/compiler.h:197 [inline]
>>> deliver_ptype_list_skb net/core/dev.c:1908 [inline]
>>> __netif_receive_skb_core+0x4630/0x4a80 net/core/dev.c:4545
>>> __netif_receive_skb net/core/dev.c:4627 [inline]
>>> process_backlog+0x62d/0xe20 net/core/dev.c:5307
>>> napi_poll net/core/dev.c:5705 [inline]
>>> net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
>>> __do_softirq+0x56d/0x93d kernel/softirq.c:285
>>> do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1040
>>> </IRQ>
>>> do_softirq kernel/softirq.c:329 [inline]
>>> __local_bh_enable_ip+0x114/0x140 kernel/softirq.c:182
>>> local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
>>> rcu_read_unlock_bh include/linux/rcupdate.h:726 [inline]
>>> __dev_queue_xmit+0x2a31/0x2b60 net/core/dev.c:3584
>>> dev_queue_xmit+0x4b/0x60 net/core/dev.c:3590
>>> packet_snd net/packet/af_packet.c:2944 [inline]
>>> packet_sendmsg+0x7c57/0x8a10 net/packet/af_packet.c:2969
>>> sock_sendmsg_nosec net/socket.c:630 [inline]
>>> sock_sendmsg net/socket.c:640 [inline]
>>> sock_write_iter+0x3b9/0x470 net/socket.c:909
>>> do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776
>>> do_iter_write+0x30d/0xd40 fs/read_write.c:932
>>> vfs_writev fs/read_write.c:977 [inline]
>>> do_writev+0x3c9/0x830 fs/read_write.c:1012
>>> SYSC_writev+0x9b/0xb0 fs/read_write.c:1085
>>> SyS_writev+0x56/0x80 fs/read_write.c:1082
>>> do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
>>> entry_SYSCALL_64_after_hwframe+0x3d/0xa2
>>> RIP: 0033:0x455259
>>> RSP: 002b:00007fb53ede8c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
>>> RAX: ffffffffffffffda RBX: 00007fb53ede96d4 RCX: 0000000000455259
>>> RDX: 0000000000000001 RSI: 00000000200010c0 RDI: 0000000000000013
>>> RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
>>> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
>>> R13: 00000000000006cd R14: 00000000006fd3d8 R15: 0000000000000000
>>>
>>> Uninit was stored to memory at:
>>> kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
>>> kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
>>> kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
>>> __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:521
>>> skb_vlan_untag+0x950/0xee0 include/linux/if_vlan.h:597
>>> __netif_receive_skb_core+0x70a/0x4a80 net/core/dev.c:4460
>>> __netif_receive_skb net/core/dev.c:4627 [inline]
>>> process_backlog+0x62d/0xe20 net/core/dev.c:5307
>>> napi_poll net/core/dev.c:5705 [inline]
>>> net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
>>> __do_softirq+0x56d/0x93d kernel/softirq.c:285
>>> Uninit was created at:
>>> kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
>>> kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
>>> kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
>>> kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
>>> slab_post_alloc_hook mm/slab.h:445 [inline]
>>> slab_alloc_node mm/slub.c:2737 [inline]
>>> __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
>>> __kmalloc_reserve net/core/skbuff.c:138 [inline]
>>> __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
>>> alloc_skb include/linux/skbuff.h:984 [inline]
>>> alloc_skb_with_frags+0x1d4/0xb20 net/core/skbuff.c:5234
>>> sock_alloc_send_pskb+0xb56/0x1190 net/core/sock.c:2085
>>> packet_alloc_skb net/packet/af_packet.c:2803 [inline]
>>> packet_snd net/packet/af_packet.c:2894 [inline]
>>> packet_sendmsg+0x6444/0x8a10 net/packet/af_packet.c:2969
>>> sock_sendmsg_nosec net/socket.c:630 [inline]
>>> sock_sendmsg net/socket.c:640 [inline]
>>> sock_write_iter+0x3b9/0x470 net/socket.c:909
>>> do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776
>>> do_iter_write+0x30d/0xd40 fs/read_write.c:932
>>> vfs_writev fs/read_write.c:977 [inline]
>>> do_writev+0x3c9/0x830 fs/read_write.c:1012
>>> SYSC_writev+0x9b/0xb0 fs/read_write.c:1085
>>> SyS_writev+0x56/0x80 fs/read_write.c:1082
>>> do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
>>> entry_SYSCALL_64_after_hwframe+0x3d/0xa2
>>> ==================================================================
>>>
>>>
>>> ---
>>> This bug is generated by a dumb bot. It may contain errors.
>>> See https://goo.gl/tpsmEJ for details.
>>> Direct all questions to [email protected].
>>>
>>> syzbot will keep track of this bug report.
>>> If you forgot to add the Reported-by tag, once the fix for this bug is
>>> merged
>>> into any tree, please reply to this email with:
>>> #syz fix: exact-commit-title
>>> To mark this as a duplicate of another syzbot report, please reply with:
>>> #syz dup: exact-subject-of-another-report
>>> If it's a one-off invalid bug report, please reply with:
>>> #syz invalid
>>> Note: if the crash happens again, it will cause creation of a new bug
>>> report.
>>> Note: all commands must start from beginning of the line in the email body.
>>>
>>> --
>>> You received this message because you are subscribed to the Google Groups
>>> "syzkaller-bugs" group.
>>> To unsubscribe from this group and stop receiving emails from it, send an
>>> email to [email protected].
>>> To view this discussion on the web visit
>>> https://groups.google.com/d/msgid/syzkaller-bugs/94eb2c059ce01f643c0569a228ee%40google.com.
>>> For more options, visit https://groups.google.com/d/optout.
>>
>>
>
> --
> Toshiaki Makita
>
On 2018/04/12 17:03, Dmitry Vyukov wrote:
> On Thu, Apr 12, 2018 at 10:01 AM, syzbot
> <[email protected]> wrote:
>> Hello,
>>
>> syzbot hit the following crash on https://github.com/google/kmsan.git/master
>> commit
>> e2ab7e8abba47a2f2698216258e5d8727ae58717 (Fri Apr 6 16:24:31 2018 +0000)
>> kmsan: temporarily disable visitAsmInstruction() to help syzbot
>> syzbot dashboard link:
>> https://syzkaller.appspot.com/bug?extid=b202b7208664142954fa
>>
>> Unfortunately, I don't have any reproducer for this crash yet.
>> Raw console output:
>> https://syzkaller.appspot.com/x/log.txt?id=5356516437655552
>> Kernel config:
>> https://syzkaller.appspot.com/x/.config?id=6627248707860932248
>> compiler: clang version 7.0.0 (trunk 329391)
>
> +Toshiaki as this seems to be related to the recent vlan tagging changes.
seems not...
"Uninit was stored to memory at:" shows uninitialized memory was stored
before where I modified the code (skb_reorder_vlan_header).
I'm not sure what this uninit memory means.
To me it looks like the memory is initialized by user provided data.
(iov in packet sock -> skb->data -> skb->protocol)
The reproducer provides 4 bytes after ethernet header, so it should be
sufficient for a vlan tag. This will set skb->len to 4 and fill the
4-byte contents in packet_snd(). skb_vlan_untag() is reading the user
provided 4-byte skb->data. It is ensured that skb_vlan_untag() does not
read beyond skb->len since it calls pskb_may_pull(). At this point I am
failing to find what I am missing.
> This also seems to be related to
> https://groups.google.com/d/msg/syzkaller-bugs/VRH9NnUi2k0/90GYsAeRBgAJ
>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: [email protected]
>> It will help syzbot understand when the bug is fixed. See footer for
>> details.
>> If you forward the report, please keep this part and the footer.
>>
>> ==================================================================
>> BUG: KMSAN: uninit-value in __read_once_size include/linux/compiler.h:197
>> [inline]
>> BUG: KMSAN: uninit-value in deliver_ptype_list_skb net/core/dev.c:1908
>> [inline]
>> BUG: KMSAN: uninit-value in __netif_receive_skb_core+0x4630/0x4a80
>> net/core/dev.c:4545
>> CPU: 0 PID: 5999 Comm: syz-executor3 Not tainted 4.16.0+ #82
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
>> Google 01/01/2011
>> Call Trace:
>> <IRQ>
>> __dump_stack lib/dump_stack.c:17 [inline]
>> dump_stack+0x185/0x1d0 lib/dump_stack.c:53
>> kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
>> __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
>> __read_once_size include/linux/compiler.h:197 [inline]
>> deliver_ptype_list_skb net/core/dev.c:1908 [inline]
>> __netif_receive_skb_core+0x4630/0x4a80 net/core/dev.c:4545
>> __netif_receive_skb net/core/dev.c:4627 [inline]
>> process_backlog+0x62d/0xe20 net/core/dev.c:5307
>> napi_poll net/core/dev.c:5705 [inline]
>> net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
>> __do_softirq+0x56d/0x93d kernel/softirq.c:285
>> do_softirq_own_stack+0x2a/0x40 arch/x86/entry/entry_64.S:1040
>> </IRQ>
>> do_softirq kernel/softirq.c:329 [inline]
>> __local_bh_enable_ip+0x114/0x140 kernel/softirq.c:182
>> local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
>> rcu_read_unlock_bh include/linux/rcupdate.h:726 [inline]
>> __dev_queue_xmit+0x2a31/0x2b60 net/core/dev.c:3584
>> dev_queue_xmit+0x4b/0x60 net/core/dev.c:3590
>> packet_snd net/packet/af_packet.c:2944 [inline]
>> packet_sendmsg+0x7c57/0x8a10 net/packet/af_packet.c:2969
>> sock_sendmsg_nosec net/socket.c:630 [inline]
>> sock_sendmsg net/socket.c:640 [inline]
>> sock_write_iter+0x3b9/0x470 net/socket.c:909
>> do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776
>> do_iter_write+0x30d/0xd40 fs/read_write.c:932
>> vfs_writev fs/read_write.c:977 [inline]
>> do_writev+0x3c9/0x830 fs/read_write.c:1012
>> SYSC_writev+0x9b/0xb0 fs/read_write.c:1085
>> SyS_writev+0x56/0x80 fs/read_write.c:1082
>> do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
>> entry_SYSCALL_64_after_hwframe+0x3d/0xa2
>> RIP: 0033:0x455259
>> RSP: 002b:00007fb53ede8c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
>> RAX: ffffffffffffffda RBX: 00007fb53ede96d4 RCX: 0000000000455259
>> RDX: 0000000000000001 RSI: 00000000200010c0 RDI: 0000000000000013
>> RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
>> R13: 00000000000006cd R14: 00000000006fd3d8 R15: 0000000000000000
>>
>> Uninit was stored to memory at:
>> kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
>> kmsan_save_stack mm/kmsan/kmsan.c:293 [inline]
>> kmsan_internal_chain_origin+0x12b/0x210 mm/kmsan/kmsan.c:684
>> __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:521
>> skb_vlan_untag+0x950/0xee0 include/linux/if_vlan.h:597
>> __netif_receive_skb_core+0x70a/0x4a80 net/core/dev.c:4460
>> __netif_receive_skb net/core/dev.c:4627 [inline]
>> process_backlog+0x62d/0xe20 net/core/dev.c:5307
>> napi_poll net/core/dev.c:5705 [inline]
>> net_rx_action+0x7c1/0x1a70 net/core/dev.c:5771
>> __do_softirq+0x56d/0x93d kernel/softirq.c:285
>> Uninit was created at:
>> kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
>> kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
>> kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
>> kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
>> slab_post_alloc_hook mm/slab.h:445 [inline]
>> slab_alloc_node mm/slub.c:2737 [inline]
>> __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
>> __kmalloc_reserve net/core/skbuff.c:138 [inline]
>> __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
>> alloc_skb include/linux/skbuff.h:984 [inline]
>> alloc_skb_with_frags+0x1d4/0xb20 net/core/skbuff.c:5234
>> sock_alloc_send_pskb+0xb56/0x1190 net/core/sock.c:2085
>> packet_alloc_skb net/packet/af_packet.c:2803 [inline]
>> packet_snd net/packet/af_packet.c:2894 [inline]
>> packet_sendmsg+0x6444/0x8a10 net/packet/af_packet.c:2969
>> sock_sendmsg_nosec net/socket.c:630 [inline]
>> sock_sendmsg net/socket.c:640 [inline]
>> sock_write_iter+0x3b9/0x470 net/socket.c:909
>> do_iter_readv_writev+0x7bb/0x970 include/linux/fs.h:1776
>> do_iter_write+0x30d/0xd40 fs/read_write.c:932
>> vfs_writev fs/read_write.c:977 [inline]
>> do_writev+0x3c9/0x830 fs/read_write.c:1012
>> SYSC_writev+0x9b/0xb0 fs/read_write.c:1085
>> SyS_writev+0x56/0x80 fs/read_write.c:1082
>> do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
>> entry_SYSCALL_64_after_hwframe+0x3d/0xa2
>> ==================================================================
>>
>>
>> ---
>> This bug is generated by a dumb bot. It may contain errors.
>> See https://goo.gl/tpsmEJ for details.
>> Direct all questions to [email protected].
>>
>> syzbot will keep track of this bug report.
>> If you forgot to add the Reported-by tag, once the fix for this bug is
>> merged
>> into any tree, please reply to this email with:
>> #syz fix: exact-commit-title
>> To mark this as a duplicate of another syzbot report, please reply with:
>> #syz dup: exact-subject-of-another-report
>> If it's a one-off invalid bug report, please reply with:
>> #syz invalid
>> Note: if the crash happens again, it will cause creation of a new bug
>> report.
>> Note: all commands must start from beginning of the line in the email body.
>>
>> --
>> You received this message because you are subscribed to the Google Groups
>> "syzkaller-bugs" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
>> email to [email protected].
>> To view this discussion on the web visit
>> https://groups.google.com/d/msgid/syzkaller-bugs/94eb2c059ce01f643c0569a228ee%40google.com.
>> For more options, visit https://groups.google.com/d/optout.
>
>
--
Toshiaki Makita
syzbot has bisected this issue to:
commit e420bed025071a623d2720a92bc2245c84757ecb
Author: Daniel Borkmann <[email protected]>
Date: Wed Jul 19 14:08:52 2023 +0000
bpf: Add fd-based tcx multi-prog infra with link support
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13dfaae6a80000
start commit: 03b123debcbc tcp: tcp_enter_quickack_mode() should be static
git tree: net-next
final oops: https://syzkaller.appspot.com/x/report.txt?x=103faae6a80000
console output: https://syzkaller.appspot.com/x/log.txt?x=17dfaae6a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=32e3dcc11fd0d297
dashboard link: https://syzkaller.appspot.com/bug?extid=b202b7208664142954fa
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15cc32e6a80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16aace14a80000
Reported-by: [email protected]
Fixes: e420bed02507 ("bpf: Add fd-based tcx multi-prog infra with link support")
For information about bisection process see: https://goo.gl/tpsmEJ#bisection