On Sun, 9 Nov 2008, Rafael J. Wysocki wrote:
> This message has been generated automatically as a part of a report
> of recent regressions.
>
> The following bug entry is on the current list of known regressions
> from 2.6.27. Please verify if it still should be listed and let me know
> (either way).
>
>
> Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=11988
> Subject : Eliminate recursive mutex in compat fb ioctl path
> Submitter : Keith Packard <[EMAIL PROTECTED]>
> Date : 2008-11-03 7:06 (7 days old)
> References : http://marc.info/?l=linux-kernel&m=122569604828448&w=4
> Handled-By : Keith Packard <[EMAIL PROTECTED]>
> Geert Uytterhoeven <[EMAIL PROTECTED]>
> Patch : http://marc.info/?l=linux-kernel&m=122569604828448&w=4
> http://lkml.org/lkml/2008/10/31/162
Fixed in mainline.
commit a684e7d33096892093456dd56a582cfc3bfad648
Author: Geert Uytterhoeven <[EMAIL PROTECTED]>
Date: Thu Nov 6 12:53:37 2008 -0800
fbdev: fix fb_compat_ioctl() deadlocks
commit 3e680aae4e53ab54cdbb0c29257dae0cbb158e1c ("fb: convert
lock/unlock_kernel() into local fb mutex") introduced several deadlocks
in the fb_compat_ioctl() path, as mutex_lock() doesn't allow recursion,
unlike lock_kernel(). This broke frame buffer applications on 64-bit
systems with a 32-bit userland.
commit 120a37470c2831fea49fdebaceb5a7039f700ce6 ("framebuffer compat_ioctl
deadlock") fixed one of the deadlocks.
This patch fixes the remaining deadlocks:
- Revert commit 120a37470c2831fea49fdebaceb5a7039f700ce6,
- Extract the core logic of fb_ioctl() into a new function do_fb_ioctl(),
- Change all callsites of fb_ioctl() where info->lock is already held to
call do_fb_ioctl() instead,
- Add sparse annotations to all routines that take info->lock.
Signed-off-by: Geert Uytterhoeven <[EMAIL PROTECTED]>
Cc: Mikulas Patocka <[EMAIL PROTECTED]>
Cc: Krzysztof Helt <[EMAIL PROTECTED]>
Cc: Alan Cox <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
With kind regards,
Geert Uytterhoeven
Software Architect
Sony Techsoft Centre Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium
Phone: +32 (0)2 700 8453
Fax: +32 (0)2 700 8622
E-mail: [EMAIL PROTECTED]
Internet: http://www.sony-europe.com/
A division of Sony Europe (Belgium) N.V.
VAT BE 0413.825.160 · RPR Brussels
Fortis · BIC GEBABEBB · IBAN BE41293037680010
--
To unsubscribe from this list: send the line "unsubscribe kernel-testers" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
