kern/188997: lock order reversal: (sleepable after non-sleepable) in lacp_attach

[asomers at gmail.com]

The following reply was made to PR kern/188997; it has been noted by GNATS.

From: asomers at gmail.com
To: bug-followup at FreeBSD.org, asomers at freebsd.org
Cc:  
Subject: Re: kern/188997: lock order reversal: (sleepable after non-sleepable)
 in lacp_attach
Date: Fri, 25 Apr 2014 13:42:27 -0600

 Forgot to include the stack trace:
 
 lock order reversal: (sleepable after non-sleepable)
 1st 0xfffff8000252ca08 if_lagg rmlock (if_lagg rmlock)
 @/usr/home/alans/freebsd/head/sys/modules/if_lagg/../../net/if_lagg.c:1040
 2nd 0xffffffff814ef4e0 sysctl lock (sysctl lock)
 @/usr/home/alans/freebsd/head/sys/kern/kern_sysctl.c:474
 KDB: stack backtrace:
 db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe00977485b0
 kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe0097748660
 witness_checkorder() at witness_checkorder+0xdc2/frame 0xfffffe00977486f0
 _sx_xlock() at _sx_xlock+0x75/frame 0xfffffe0097748730
 sysctl_add_oid() at sysctl_add_oid+0x4a/frame 0xfffffe0097748780
 lacp_attach() at lacp_attach+0xf7/frame 0xfffffe00977487f0
 lagg_lacp_attach() at lagg_lacp_attach+0x88/frame 0xfffffe0097748810
 lagg_ioctl() at lagg_ioctl+0x98a/frame 0xfffffe00977488f0
 in_control() at in_control+0x38e/frame 0xfffffe0097748970
 ifioctl() at ifioctl+0xba2/frame 0xfffffe0097748a30
 kern_ioctl() at kern_ioctl+0x22b/frame 0xfffffe0097748a90
 sys_ioctl() at sys_ioctl+0x13c/frame 0xfffffe0097748ae0
 amd64_syscall() at amd64_syscall+0x25a/frame 0xfffffe0097748bf0
 Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0097748bf0
 --- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x800fa045a, rsp
 =0x7fffffffe118, rbp = 0x7fffffffe1a0 ---
 uma_zalloc_arg: zone "128" with the following non-sleepable locks held:
 exclusive rm if_lagg rmlock (if_lagg rmlock) r = 0
 (0xfffff8000252ca08) locked
 @/usr/home/alans/freebsd/head/sys/modules/if_lagg/../../net/if_lagg.c:1040
 KDB: stack backtrace:
 db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0097748500
 kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe00977485b0
 witness_warn() at witness_warn+0x4b5/frame 0xfffffe0097748670
 uma_zalloc_arg() at uma_zalloc_arg+0x3b/frame 0xfffffe00977486e0
 malloc() at malloc+0x194/frame 0xfffffe0097748730
 sysctl_add_oid() at sysctl_add_oid+0x11f/frame 0xfffffe0097748780
 lacp_attach() at lacp_attach+0xf7/frame 0xfffffe00977487f0
 lagg_lacp_attach() at lagg_lacp_attach+0x88/frame 0xfffffe0097748810
 lagg_ioctl() at lagg_ioctl+0x98a/frame 0xfffffe00977488f0
 in_control() at in_control+0x38e/frame 0xfffffe0097748970
 ifioctl() at ifioctl+0xba2/frame 0xfffffe0097748a30
 kern_ioctl() at kern_ioctl+0x22b/frame 0xfffffe0097748a90
 sys_ioctl() at sys_ioctl+0x13c/frame 0xfffffe0097748ae0
 amd64_syscall() at amd64_syscall+0x25a/frame 0xfffffe0097748bf0
 Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0097748bf0
 --- syscall (54, FreeBSD ELF64, sys_ioctl), rip = 0x800fa045a, rsp =
 0x7fffffffe118, rbp = 0x7fffffffe1a0 ---