On Wed, Feb 19, 2020 at 9:31 AM Dmitry Vyukov [off-list ref] wrote:
On Sun, Jun 30, 2019 at 7:19 AM Hillf Danton [off-list ref] wrote:
quoted
Hello,
On Sat, 29 Jun 2019 08:47:06 -0700 (PDT)
quoted
syzbot found the following crash on:
HEAD commit: ee7dd773 sis900: remove TxIDLE
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17ceb9a9a00000
kernel config: https://syzkaller.appspot.com/x/.config?x=7ac9edef4d37e5fb
dashboard link: https://syzkaller.appspot.com/bug?extid=1a68504d96cd17b33a05
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=119b2a13a00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13127bada00000
The bug was bisected to:
Hm... I doubt it is e9c1a793210f ("tipc: add dst_cache support for udp media")
based on one of the lines dumped:
> tipc_udp_xmit.isra.0+0xc4/0xb80 net/tipc/udp_media.c:164
And getting the local bottom half disabled looks like a teaspoon of
cough syrup.
---
--- a/net/tipc/udp_media.c
+++ b/net/tipc/udp_media.c
@@ -224,6 +224,8 @@ static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
struct udp_bearer *ub;
int err = 0;
+ local_bh_disable();
+
if (skb_headroom(skb) < UDP_MIN_HEADROOM) {
err = pskb_expand_head(skb, UDP_MIN_HEADROOM, 0, GFP_ATOMIC);
if (err)@@ -237,9 +239,12 @@ static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
goto out;
}
- if (addr->broadcast != TIPC_REPLICAST_SUPPORT)
- return tipc_udp_xmit(net, skb, ub, src, dst,
+ if (addr->broadcast != TIPC_REPLICAST_SUPPORT) {
+ err = tipc_udp_xmit(net, skb, ub, src, dst,
&ub->rcast.dst_cache);
+ local_bh_enable();
+ return err;
+ }
/* Replicast, send an skb to each configured IP address */
list_for_each_entry_rcu(rcast, &ub->rcast.list, list) {@@ -259,6 +264,7 @@ static int tipc_udp_send_msg(struct net *net, struct sk_buff *skb,
err = 0;
out:
kfree_skb(skb);
+ local_bh_enable();
return err;
}
--
quoted
commit 52dfae5c85a4c1078e9f1d5e8947d4a25f73dd81
Author: Jon Maloy [off-list ref]
Date: Thu Mar 22 19:42:52 2018 +0000
tipc: obtain node identity from interface by default
What is the fate of this fix?
There is also another fix for this pending for half a year as far as I can tell.
This is one of the top crashes and it prevents most other kernel
testing from happening. All kernels just crash on this right away.
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
+jmaloy new email address
quoted
quoted
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=160ad903a00000
final crash: https://syzkaller.appspot.com/x/report.txt?x=150ad903a00000
console output: https://syzkaller.appspot.com/x/log.txt?x=110ad903a00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: <redacted>
Fixes: 52dfae5c85a4 ("tipc: obtain node identity from interface by default")
Started in network mode
Own node identity 7f000001, cluster identity 4711
New replicast peer: 172.20.20.22
check_preemption_disabled: 3 callbacks suppressed
BUG: using smp_processor_id() in preemptible [00000000] code:
syz-executor834/8612
caller is dst_cache_get+0x3d/0xb0 net/core/dst_cache.c:68
CPU: 0 PID: 8612 Comm: syz-executor834 Not tainted 5.2.0-rc6+ #48
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x172/0x1f0 lib/dump_stack.c:113
check_preemption_disabled lib/smp_processor_id.c:47 [inline]
debug_smp_processor_id+0x251/0x280 lib/smp_processor_id.c:57
dst_cache_get+0x3d/0xb0 net/core/dst_cache.c:68
tipc_udp_xmit.isra.0+0xc4/0xb80 net/tipc/udp_media.c:164
tipc_udp_send_msg+0x29a/0x4b0 net/tipc/udp_media.c:254
tipc_bearer_xmit_skb+0x16c/0x360 net/tipc/bearer.c:503
tipc_enable_bearer+0xabe/0xd20 net/tipc/bearer.c:328
__tipc_nl_bearer_enable+0x2de/0x3a0 net/tipc/bearer.c:899
tipc_nl_bearer_enable+0x23/0x40 net/tipc/bearer.c:907
genl_family_rcv_msg+0x74b/0xf90 net/netlink/genetlink.c:629
genl_rcv_msg+0xca/0x16c net/netlink/genetlink.c:654
netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
genl_rcv+0x29/0x40 net/netlink/genetlink.c:665
netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328
netlink_sendmsg+0x8ae/0xd70 net/netlink/af_netlink.c:1917
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xd7/0x130 net/socket.c:665
___sys_sendmsg+0x803/0x920 net/socket.c:2286
__sys_sendmsg+0x105/0x1d0 net/socket.c:2324
__do_sys_sendmsg net/socket.c:2333 [inline]
__se_sys_sendmsg net/socket.c:2331 [inline]
__x64_sys_sendmsg+0x78/0xb0 net/socket.c:2331
do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x444679
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 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 0f 83 1b d8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fff0201a8b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002e0 RCX: 0000000000444679
RDX: 0000000000000000 RSI: 0000000020000580 RDI: 0000000000000003
RBP: 00000000006cf018 R08: 0000000000000001 R09: 00000000004002e0
R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000402320
R13: 00000000004023b0 R14: 0000000000000000 R15: 0000000000
---
This bug 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 bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches
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