From: Blaisorblade <blaisorblade@yahoo.it>
To: user-mode-linux-devel@lists.sourceforge.net
Cc: Rob Landley <rob@landley.net>, linux-kernel@vger.kernel.org
Subject: Re: [uml-devel] kernel BUG at drivers/block/loop.c:621
Date: Sat, 18 Mar 2006 01:24:18 +0100 [thread overview]
Message-ID: <200603180124.19077.blaisorblade@yahoo.it> (raw)
In-Reply-To: <200603171912.12082.rob@landley.net>
On Saturday 18 March 2006 01:12, Rob Landley wrote:
> I can reproduce the following in 2.6.16-rc5, User Mode Linux:
>
> kernel BUG at drivers/block/loop.c:621!
> Kernel panic - not syncing: BUG!
>
> EIP: 0073:[<ffffe410>] CPU: 0 Not tainted ESP: 007b:b7de1f9c EFLAGS:
> 00200246 Not tainted
> EAX: 00000000 EBX: 000018be ECX: 00000013 EDX: 000018be
> ESI: 000018bb EDI: 00000011 EBP: b7de1fb8 DS: 007b ES: 007b
> 09b87bb4: [<0806c762>] show_regs+0x102/0x110
> 09b87bd0: [<0805b6fc>] panic_exit+0x2c/0x50
> 09b87be0: [<0807ff7d>] notifier_call_chain+0x2d/0x50
> 09b87c00: [<08071095>] panic+0x75/0x120
> 09b87c20: [<0812e181>] loop_thread+0x151/0x160
> 09b87c4c: [<08065297>] run_kernel_thread+0x37/0x60
> 09b87cfc: [<0805bbd1>] new_thread_handler+0x91/0xc0
The below is strange - GCC is putting disks in the .text section or kallsyms
has some bug.
> 09b87d20: [<ffffe420>] disks+0xf7e7ec84/0x4
> The reproduction sequence is a bit involved (my mount regression test and
> the current svn snapshot of busybox are involved), and running the
> following sequence of commands:
>
> mount; mount -a; mount; mount /dev/loop1 /images/vfat.dir ;
> losetup /dev/loop1; ls; vi /etc/fstab; cat /etc/fstab; losetup /dev/loop0;
> mount /images/vfat.img /images/vfat.dir -o ro
>
> The current busybox mount is still broken in a couple of known places
> (hence the testing; I'm fixing it). But it probably shouldn't panic the
> kernel...
*) Is this reproducible on host?
*) I don't understand yet what UML may be doing wrong.
*) look at: that spin_lock (SMP kernel? SPINLOCK_DEBUG? Try enabling the
latter and see what happens).
(a bio is a block I/O request)
*) given what the code says, on that line bio is NULL, i.e. loop_get_bio
returned NULL, i.e. (I guess) wait_for_completion_interruptible returned,
because someone else (loop_make_request) did "complete" on its param, but
incorrectly as the "someone else" hadn't filled the lo->lo_bio.
--
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894)
http://www.user-mode-linux.org/~blaisorblade
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WARNING: multiple messages have this Message-ID (diff)
From: Blaisorblade <blaisorblade@yahoo.it>
To: user-mode-linux-devel@lists.sourceforge.net
Cc: Rob Landley <rob@landley.net>, linux-kernel@vger.kernel.org
Subject: Re: [uml-devel] kernel BUG at drivers/block/loop.c:621
Date: Sat, 18 Mar 2006 01:24:18 +0100 [thread overview]
Message-ID: <200603180124.19077.blaisorblade@yahoo.it> (raw)
In-Reply-To: <200603171912.12082.rob@landley.net>
On Saturday 18 March 2006 01:12, Rob Landley wrote:
> I can reproduce the following in 2.6.16-rc5, User Mode Linux:
>
> kernel BUG at drivers/block/loop.c:621!
> Kernel panic - not syncing: BUG!
>
> EIP: 0073:[<ffffe410>] CPU: 0 Not tainted ESP: 007b:b7de1f9c EFLAGS:
> 00200246 Not tainted
> EAX: 00000000 EBX: 000018be ECX: 00000013 EDX: 000018be
> ESI: 000018bb EDI: 00000011 EBP: b7de1fb8 DS: 007b ES: 007b
> 09b87bb4: [<0806c762>] show_regs+0x102/0x110
> 09b87bd0: [<0805b6fc>] panic_exit+0x2c/0x50
> 09b87be0: [<0807ff7d>] notifier_call_chain+0x2d/0x50
> 09b87c00: [<08071095>] panic+0x75/0x120
> 09b87c20: [<0812e181>] loop_thread+0x151/0x160
> 09b87c4c: [<08065297>] run_kernel_thread+0x37/0x60
> 09b87cfc: [<0805bbd1>] new_thread_handler+0x91/0xc0
The below is strange - GCC is putting disks in the .text section or kallsyms
has some bug.
> 09b87d20: [<ffffe420>] disks+0xf7e7ec84/0x4
> The reproduction sequence is a bit involved (my mount regression test and
> the current svn snapshot of busybox are involved), and running the
> following sequence of commands:
>
> mount; mount -a; mount; mount /dev/loop1 /images/vfat.dir ;
> losetup /dev/loop1; ls; vi /etc/fstab; cat /etc/fstab; losetup /dev/loop0;
> mount /images/vfat.img /images/vfat.dir -o ro
>
> The current busybox mount is still broken in a couple of known places
> (hence the testing; I'm fixing it). But it probably shouldn't panic the
> kernel...
*) Is this reproducible on host?
*) I don't understand yet what UML may be doing wrong.
*) look at: that spin_lock (SMP kernel? SPINLOCK_DEBUG? Try enabling the
latter and see what happens).
(a bio is a block I/O request)
*) given what the code says, on that line bio is NULL, i.e. loop_get_bio
returned NULL, i.e. (I guess) wait_for_completion_interruptible returned,
because someone else (loop_make_request) did "complete" on its param, but
incorrectly as the "someone else" hadn't filled the lo->lo_bio.
--
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894)
http://www.user-mode-linux.org/~blaisorblade
___________________________________
Yahoo! Messenger with Voice: chiama da PC a telefono a tariffe esclusive
http://it.messenger.yahoo.com
next prev parent reply other threads:[~2006-03-18 0:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-18 0:12 [uml-devel] kernel BUG at drivers/block/loop.c:621 Rob Landley
2006-03-18 0:12 ` Rob Landley
2006-03-18 0:24 ` Blaisorblade [this message]
2006-03-18 0:24 ` [uml-devel] " Blaisorblade
2006-03-18 0:55 ` Rob Landley
2006-03-18 0:55 ` Rob Landley
2006-03-18 1:04 ` Blaisorblade
2006-03-18 1:04 ` Blaisorblade
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