lock order reversal

[Bjoern A. Zeeb]

On Fri, 12 Aug 2005, Thierry Herbelot wrote:

Hi,

Cc: current

> (this is on a very recent -Current, on a UP machine,
> with a straight GENERIC kernel)
>
> lock order reversal
> 1st 0xc09242c0 Giant (Giant) @ /usr/src/sys/kern/vfs_mount.c:502
> 2nd 0xc0974c6c udp (udp) @ /usr/src/sys/netinet/udp_usrreq.c:926
> KDB: stack backtrace:
> kdb_backtrace(0,ffffffff,c09356e8,c0935378,c08bf804) at kdb_backtrace+0x29
> witness_checkorder(c0974c6c,9,c0869ee4,39e) at witness_checkorder+0x564
> _mtx_lock_flags(c0974c6c,0,c0869ee4,39e) at _mtx_lock_flags+0x5b
> udp_attach(c179b2c8,0,c09223c0,c1a10000,c165fd80) at udp_attach+0x1e
> socreate(2,c1a10100,2,0,c1a00780) at socreate+0x122
> nfs_connect(c1a10000,0,c062b558,c106c968,1) at nfs_connect+0xb9
> mountnfs(cb750a24,c165cc00,c14de9e0,cb7509c4,cb750978) at mountnfs+0x215
> nfs_mount(c165cc00,c165fd80,0,0,c175d770) at nfs_mount+0x17a
> vfs_domount(c165fd80,c153d240,c1532990,0,c1680ab0) at vfs_domount+0x589
> vfs_donmount(c165fd80,0,cb750c08,c1a00880,c) at vfs_donmount+0xce
> kernel_mount(c1541650,0,c1541650,c086c8d5,cb750c50) at kernel_mount+0x6d
> nfs_cmount(c1541650,bfbfeb90,0,c165fd80,c08cf0e0) at nfs_cmount+0x39
> mount(c165fd80,cb750d04,4,d,246) at mount+0x156
> syscall(3b,3b,3b,bfbfed74,bfbfeb90) at syscall+0x22f
> Xint0x80_syscall() at Xint0x80_syscall+0x1f
> --- syscall (21, FreeBSD ELF32, mount), eip = 0x280b7f63, esp = 0xbfbfe74c,
> ebp = 0xbfbfec08 ---
>
> CVS idents :
>
> /usr/src/sys/kern/vfs_mount.c:
>      $FreeBSD: src/sys/kern/vfs_mount.c,v 1.196 2005/05/18 22:05:12 pjd Exp $
> /usr/src/sys/netinet/udp_usrreq.c:
>      $FreeBSD: src/sys/netinet/udp_usrreq.c,v 1.175 2005/06/01 11:24:00
> rwatson Exp $


Added with ID 126, see http://sources.zabbadoz.net/freebsd/lor.html#126

Thanks for reporting.

-- 
Bjoern A. Zeeb				bzeeb at Zabbadoz dot NeT