| Message ID | 20180509170546.247826-1-edumazet@google.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] net/ipv6: fix lock imbalance in ip6_route_del() | expand |
On 5/9/18 11:05 AM, Eric Dumazet wrote: > WARNING: lock held when returning to user space! > 4.17.0-rc3+ #37 Not tainted > > syz-executor1/27662 is leaving the kernel with locks still held! > 1 lock held by syz-executor1/27662: > #0: 00000000f661aee7 (rcu_read_lock){....}, at: ip6_route_del+0xea/0x13f0 net/ipv6/route.c:3206 > BUG: scheduling while atomic: syz-executor1/27662/0x00000002 > INFO: lockdep is turned off. > Modules linked in: > Kernel panic - not syncing: scheduling while atomic > > CPU: 1 PID: 27662 Comm: syz-executor1 Not tainted 4.17.0-rc3+ #37 ... > > Fixes: 23fb93a4d3f1 ("net/ipv6: Cleanup exception and cache route handling") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Cc: David Ahern <dsahern@gmail.com> > Reported-by: syzbot <syzkaller@googlegroups.com> > --- > net/ipv6/route.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > Acked-by: David Ahern <dsahern@gmail.com> Thanks for the fix, Eric.
On 05/09/2018 10:05 AM, Eric Dumazet wrote: > WARNING: lock held when returning to user space! > 4.17.0-rc3+ #37 Not tainted > > > Fixes: 23fb93a4d3f1 ("net/ipv6: Cleanup exception and cache route handling") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Cc: David Ahern <dsahern@gmail.com> > Reported-by: syzbot <syzkaller@googlegroups.com> > --- This targets net-next tree, not tree, sorry for the typo.
From: Eric Dumazet <edumazet@google.com> Date: Wed, 9 May 2018 10:05:46 -0700 > WARNING: lock held when returning to user space! > 4.17.0-rc3+ #37 Not tainted ... > Fixes: 23fb93a4d3f1 ("net/ipv6: Cleanup exception and cache route handling") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Cc: David Ahern <dsahern@gmail.com> > Reported-by: syzbot <syzkaller@googlegroups.com> Applied to net-next.
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index daa3662da0ee809422db12f0ff58c7975b0b8be7..af0416701fb21c71f8b0f2dec9f0ada479cb9152 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -3224,8 +3224,10 @@ static int ip6_route_del(struct fib6_config *cfg, &cfg->fc_src); if (rt_cache) { rc = ip6_del_cached_rt(rt_cache, cfg); - if (rc != -ESRCH) + if (rc != -ESRCH) { + rcu_read_unlock(); return rc; + } } continue; }
WARNING: lock held when returning to user space! 4.17.0-rc3+ #37 Not tainted syz-executor1/27662 is leaving the kernel with locks still held! 1 lock held by syz-executor1/27662: #0: 00000000f661aee7 (rcu_read_lock){....}, at: ip6_route_del+0xea/0x13f0 net/ipv6/route.c:3206 BUG: scheduling while atomic: syz-executor1/27662/0x00000002 INFO: lockdep is turned off. Modules linked in: Kernel panic - not syncing: scheduling while atomic CPU: 1 PID: 27662 Comm: syz-executor1 Not tainted 4.17.0-rc3+ #37 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+0x1b9/0x294 lib/dump_stack.c:113 panic+0x22f/0x4de kernel/panic.c:184 __schedule_bug.cold.85+0xdf/0xdf kernel/sched/core.c:3290 schedule_debug kernel/sched/core.c:3307 [inline] __schedule+0x139e/0x1e30 kernel/sched/core.c:3412 schedule+0xef/0x430 kernel/sched/core.c:3549 exit_to_usermode_loop+0x220/0x310 arch/x86/entry/common.c:152 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:265 [inline] do_syscall_64+0x6ac/0x800 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x455979 RSP: 002b:00007fbf4051dc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 00007fbf4051e6d4 RCX: 0000000000455979 RDX: 00000000200001c0 RSI: 000000000000890c RDI: 0000000000000013 RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000003c8 R14: 00000000006f9b60 R15: 0000000000000000 Dumping ftrace buffer: (ftrace buffer empty) Kernel Offset: disabled Rebooting in 86400 seconds.. Fixes: 23fb93a4d3f1 ("net/ipv6: Cleanup exception and cache route handling") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: David Ahern <dsahern@gmail.com> Reported-by: syzbot <syzkaller@googlegroups.com> --- net/ipv6/route.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)