From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 21 Mar 2003 12:39:19 -0800 From: Andrew Morton Subject: Re: [BUG] 2.5.65-mm3 kernel BUG at fs/ext3/super.c:1795! Message-Id: <20030321123919.0b8b1b86.akpm@digeo.com> In-Reply-To: <8765qchhgo.fsf@lapper.ihatent.com> References: <20030320235821.1e4ff308.akpm@digeo.com> <8765qchhgo.fsf@lapper.ihatent.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Alexander Hoogerhuis Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Alexander Hoogerhuis wrote: > > Andrew Morton writes: > > > > [SNIP] > > > > Disk I/O on my machine froze up during very light work after a few > hours, luckily I had a window open on another machine so I could do a > simple capture and save the info: > > kernel BUG at fs/ext3/super.c:1795! > invalid operand: 0000 [#1] > CPU: 0 > EIP: 0060:[] Not tainted VLI > EFLAGS: 00010246 > EIP is at ext3_write_super+0x36/0x94 > eax: 00000000 ebx: c8834000 ecx: efb5904c edx: efb59000 > esi: efb59000 edi: c8834000 ebp: c8835ecc esp: c8835ec0 > ds: 007b es: 007b ss: 0068 > Process pdflush (pid: 7853, threadinfo=c8834000 task=ed0a5880) > Stack: c8835ee4 00000287 efb5904c c8835ee4 c0153148 efb59000 00000077 51eb851f > c8835fcc c8835fa4 c0137fd0 c03892fc 007b9f47 007b168f 00000000 00000000 > c8835ef4 00000000 00000001 00000000 00000001 00000000 00000053 00000000 > Call Trace: > [] sync_supers+0xde/0xea > [] wb_kupdate+0x68/0x161 > [] schedule+0x1a4/0x3ac > [] __pdflush+0xdc/0x1d8 > [] pdflush+0x0/0x15 > [] pdflush+0x11/0x15 > [] wb_kupdate+0x0/0x161 > [] kernel_thread_helper+0x5/0xb How on earth did you do that? sync_supers() does lock_super, then calls ext3_write_super. ext3_write_super() does a down_trylock() on sb->s_lock and goes BUG if it acquired the lock. So you've effectively done this: down(&sem); if (down_trylock(&sem)) BUG(); This can only be a random memory scribble, a hardware bug or a preempt-related bug in down_trylock(). -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org