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Andy Whitcroft reported an oops in aoe triggered by use of an
incorrectly initialised request_queue object:
[ 2645.959090] kobject '<NULL>' (ffff880059ca22c0): tried to add
an uninitialized object, something is seriously wrong.
[ 2645.959104] Pid: 6, comm: events/0 Not tainted 2.6.31-5-generic #24-Ubuntu
[ 2645.959107] Call Trace:
[ 2645.959139] [<ffffffff8126ca2f>] kobject_add+0x5f/0x70
[ 2645.959151] [<ffffffff8125b4ab>] blk_register_queue+0x8b/0xf0
[ 2645.959155] [<ffffffff8126043f>] add_disk+0x8f/0x160
[ 2645.959161] [<ffffffffa01673c4>] aoeblk_gdalloc+0x164/0x1c0 [aoe]
The request queue of an aoe device is not used but can be allocated in
code that does not sleep.
Bruno bisected this regression down to
cd43e26f071524647e660706b784ebcbefbd2e44
block: Expose stacked device queues in sysfs
"This seems to generate /sys/block/$device/queue and its contents for
everyone who is using queues, not just for those queues that have a
non-NULL queue->request_fn."
Addresses http://bugs.launchpad.net/bugs/410198
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13942
Note that embedding a queue inside another object has always been
an illegal construct, since the queues are reference counted and
must persist until the last reference is dropped. So aoe was
always buggy in this respect (Jens).
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Bruno Premont <bonbons@linux-vserver.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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Reinette Chatre reports a frozen system (with blinking keyboard LEDs)
when switching from graphics mode to the text console, or when
suspending (which does the same thing). With netconsole, the oops
turned out to be
BUG: unable to handle kernel NULL pointer dereference at 0000000000000084
IP: [<ffffffffa03ecaab>] i915_driver_irq_handler+0x26b/0xd20 [i915]
and it's due to the i915_gem.c code doing drm_irq_uninstall() after
having done i915_gem_idle(). And the i915_gem_idle() path will do
i915_gem_idle() ->
i915_gem_cleanup_ringbuffer() ->
i915_gem_cleanup_hws() ->
dev_priv->hw_status_page = NULL;
but if an i915 interrupt comes in after this stage, it may want to
access that hw_status_page, and gets the above NULL pointer dereference.
And since the NULL pointer dereference happens from within an interrupt,
and with the screen still in graphics mode, the common end result is
simply a silently hung machine.
Fix it by simply uninstalling the irq handler before idling rather than
after. Fixes
http://bugzilla.kernel.org/show_bug.cgi?id=13819
Reported-and-tested-by: Reinette Chatre <reinette.chatre@intel.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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eDP is exclusive connector too, and add missing crtc_mask
setting for TV.
This fixes
http://bugzilla.kernel.org/show_bug.cgi?id=14139
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Reported-and-tested-by: Carlos R. Mafra <crmafra2@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm/radeon/kms: add LTE/GTE discard + rv515 two sided stencil register.
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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
IMA: update ima_counts_put
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* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
gianfar: Fix build.
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* git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide-2.6:
pcmcia: add CNF-CDROM-ID for ide
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git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/anholt/drm-intel:
agp/intel: support for new chip variant of IGDNG mobile
drm/i915: Unref old_obj on get_fence_reg() error path
drm/i915: increase default latency constant (v2 w/comment)
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This adds some rv350+ register for LTE/GTE discard,
and enables the rv515 two sided stencil register.
It also disables the DEPTHXY_OFFSET register which
can be used to workaround the CS checker.
Moves rs690 to proper place in rs600 and uses correct
table on rs600.
Signed-off-by: Dave Airlie <airlied@redhat.com>
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- As ima_counts_put() may be called after the inode has been freed,
verify that the inode is not NULL, before dereferencing it.
- Maintain the IMA file counters in may_open() properly, decrementing
any counter increments on subsequent errors.
Reported-by: Ciprian Docan <docan@eden.rutgers.edu>
Reported-by: J.R. Okajima <hooanon05@yahoo.co.jp>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Eric Paris <eparis@redhat.com
Signed-off-by: James Morris <jmorris@namei.org>
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Reported by Michael Guntsche <mike@it-loops.com>
--------------------
Commit
38bddf04bcfe661fbdab94888c3b72c32f6873b3 gianfar: gfar_remove needs to call unregister_netdev()
breaks the build of the gianfar driver because "dev" is undefined in
this function. To quickly test rc9 I changed this to priv->ndev but I do
not know if this is the correct one.
--------------------
Signed-off-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
firewire: sbp2: fix freeing of unallocated memory
firewire: ohci: fix Ricoh R5C832, video reception
firewire: ohci: fix Agere FW643 and multiple cameras
firewire: core: fix crash in iso resource management
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This patch fixes a null pointer exception caused by removal of
'ack()' for level interrupts in the Xilinx interrupt driver. A recent
change to the xilinx interrupt controller removed the ack hook for
level irqs.
Signed-off-by: Roderick Colenbrander <thunderbird2k@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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* git://git.infradead.org/~dwmw2/mtd-2.6.31:
JFFS2: add missing verify buffer allocation/deallocation
mtd: nftl: fix offset alignments
mtd: nftl: write support is broken
mtd: m25p80: fix null pointer dereference bug
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* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
block: Allow changing max_sectors_kb above the default 512
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git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
* 'fix/oxygen' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
sound: oxygen: handle cards with missing EEPROM
sound: oxygen: fix MCLK rate for 192 kHz playback
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* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
tc: Fix unitialized kernel memory leak
pkt_sched: Revert tasklet_hrtimer changes.
net: sk_free() should be allowed right after sk_alloc()
gianfar: gfar_remove needs to call unregister_netdev()
ipw2200: firmware DMA loading rework
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* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
crypto: skcipher - Fix skcipher_dequeue_givcrypt NULL test
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git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq:
[CPUFREQ] Re-enable cpufreq suspend and resume code
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git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
[IA64] fix csum_ipv6_magic()
[IA64] Fix warning in dma-mapping.c
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* 'for-linus' of git://oss.sgi.com/xfs/xfs:
xfs: actually enable the swapext compat handler
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git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ryusuke/nilfs2:
nilfs2: fix preempt count underflow in nilfs_btnode_prepare_change_key
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu: don't assume existence of cpu0
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git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6
* 'slab/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
slub: Fix kmem_cache_destroy() with SLAB_DESTROY_BY_RCU
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* git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm:
dm snapshot: fix on disk chunk size validation
dm exception store: split set_chunk_size
dm snapshot: fix header corruption race on invalidation
dm snapshot: refactor zero_disk_area to use chunk_io
dm log: userspace add luid to distinguish between concurrent log instances
dm raid1: do not allow log_failure variable to unset after being set
dm log: remove incorrect field from userspace table output
dm log: fix userspace status output
dm stripe: expose correct io hints
dm table: add more context to terse warning messages
dm table: fix queue_limit checking device iterator
dm snapshot: implement iterate devices
dm multipath: fix oops when request based io fails when no paths
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git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
PCI SR-IOV: correct broken resource alignment calculations
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* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-2.6:
sparc64: Fix bootup with mcount in some configs.
sparc64: Kill spurious NMI watchdog triggers by increasing limit to 30 seconds.
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf_counter/powerpc: Fix cache event codes for POWER7
perf_counter: Fix /0 bug in swcounters
perf_counters: Increase paranoia level
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git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: atkbd - add Compaq Presario R4000-series repeat quirk
Input: i8042 - add Acer Aspire 5536 to the nomux list
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In ext2_rename(), dir_page is acquired through ext2_dotdot(). It is
then released through ext2_set_link() but only if old_dir != new_dir.
Failing that, the pkmap reference count is never decremented and the
page remains pinned forever. Repeat that a couple times with highmem
pages and all pkmap slots get exhausted, and every further kmap() calls
end up stalling on the pkmap_map_wait queue at which point the whole
system comes to a halt.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Acked-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2:
ocfs2: ocfs2_write_begin_nolock() should handle len=0
ocfs2: invalidate dentry if its dentry_lock isn't initialized.
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The whole write-room thing is something that is up to the _caller_ to
worry about, not the pty layer itself. The total buffer space will
still be limited by the buffering routines themselves, so there is no
advantage or need in having pty_write() artificially limit the size
somehow.
And what happened was that the caller (the n_tty line discipline, in
this case) may have verified that there is room for 2 bytes to be
written (for NL -> CRNL expansion), and it used to then do those writes
as two single-byte writes. And if the first byte written (CR) then
caused a new tty buffer to be allocated, pty_space() may have returned
zero when trying to write the second byte (LF), and then incorrectly
failed the write - leading to a lost newline character.
This should finally fix
http://bugzilla.kernel.org/show_bug.cgi?id=14015
Reported-by: Mikael Pettersson <mikpe@it.uu.se>
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When translating CR to CRNL in the n_tty line discipline, we did it as
two tty_put_char() calls. Which works, but is stupid, and has caused
problems before too with bad interactions with the write_room() logic.
The generic USB serial driver had that problem, for example.
Now the pty layer had similar issues after being moved to the generic
tty buffering code (in commit d945cb9cce20ac7143c2de8d88b187f62db99bdc:
"pty: Rework the pty layer to use the normal buffering logic").
So stop doing the silly separate two writes, and do it as a single write
instead. That's what the n_tty layer already does for the space
expansion of tabs (XTABS), and it means that we'll now always have just
a single write for the CRNL to match the single 'tty_write_room()' test,
which hopefully means that the next time somebody screws up buffering,
it won't cause weeks of debugging.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tom Horsley reports that his debugger hangs when it tries to read
/proc/pid_of_tracee/maps, this happens since
"mm_for_maps: take ->cred_guard_mutex to fix the race with exec"
04b836cbf19e885f8366bccb2e4b0474346c02d
commit in 2.6.31.
But the root of the problem lies in the fact that do_execve() path calls
tracehook_report_exec() which can stop if the tracer sets PT_TRACE_EXEC.
The tracee must not sleep in TASK_TRACED holding this mutex. Even if we
remove ->cred_guard_mutex from mm_for_maps() and proc_pid_attr_write(),
another task doing PTRACE_ATTACH should not hang until it is killed or the
tracee resumes.
With this patch do_execve() does not use ->cred_guard_mutex directly and
we do not hold it throughout, instead:
- introduce prepare_bprm_creds() helper, it locks the mutex
and calls prepare_exec_creds() to initialize bprm->cred.
- install_exec_creds() drops the mutex after commit_creds(),
and thus before tracehook_report_exec()->ptrace_stop().
or, if exec fails,
free_bprm() drops this mutex when bprm->cred != NULL which
indicates install_exec_creds() was not called.
Reported-by: Tom Horsley <tom.horsley@att.net>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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disabled
On low-memory systems, anti-fragmentation gets disabled as fragmentation
cannot be avoided on a sufficiently large boundary to be worthwhile. Once
disabled, there is a period of time when all the pageblocks are marked
MOVABLE and the expectation is that they get marked UNMOVABLE at each call
to __rmqueue_fallback().
However, when MAX_ORDER is large the pageblocks do not change ownership
because the normal criteria are not met. This has the effect of
prematurely breaking up too many large contiguous blocks. This is most
serious on NOMMU systems which depend on high-order allocations to boot.
This patch causes pageblocks to change ownership on every fallback when
anti-fragmentation is disabled. This prevents the large blocks being
prematurely broken up.
This is a fix to commit 49255c619fbd482d704289b5eb2795f8e3b7ff2e [page
allocator: move check for disabled anti-fragmentation out of fastpath] and
the problem affects 2.6.31-rc8.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Tested-by: Paul Mundt <lethal@linux-sh.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix the error handling in do_mmap_pgoff(). If do_mmap_shared_file() or
do_mmap_private() fail, we jump to the error_put_region label at which
point we cann __put_nommu_region() on the region - but we haven't yet
added the region to the tree, and so __put_nommu_region() may BUG
because the region tree is empty or it may corrupt the region tree.
To get around this, we can afford to add the region to the region tree
before calling do_mmap_shared_file() or do_mmap_private() as we keep
nommu_region_sem write-locked, so no-one can race with us by seeing a
transient region.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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cancel_delayed_work() has to use del_timer_sync() to guarantee the timer
function is not running after return. But most users doesn't actually
need this, and del_timer_sync() has problems: it is not useable from
interrupt, and it depends on every lock which could be taken from irq.
Introduce __cancel_delayed_work() which calls del_timer() instead.
The immediate reason for this patch is
http://bugzilla.kernel.org/show_bug.cgi?id=13757
but hopefully this helper makes sense anyway.
As for 13757 bug, actually we need requeue_delayed_work(), but its
semantics are not yet clear.
Merge this patch early to resolves cross-tree interdependencies between
input and infiniband.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Roland Dreier <rdreier@cisco.com>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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If a target writes invalid status (typically status of a command that
already timed out), firewire-sbp2 attempts to put away an ORB that
doesn't exist. https://bugzilla.redhat.com/show_bug.cgi?id=519772
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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In dual-buffer DMA mode, no video frames are ever received from R5C832
by libdc1394. Fallback to packet-per-buffer DMA works reliably.
http://thread.gmane.org/gmane.linux.kernel.firewire.devel/13393/focus=13476
Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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An Agere FW643 OHCI 1.1 card works fine for video reception from one
camera but fails early if receiving from two cameras. After a short
while, no IR IRQ events occur and the context control register does not
react anymore. This happens regardless whether both IR DMA contexts are
dual-buffer or one is dual-buffer and the other packet-per-buffer.
This can be worked around by disabling dual buffer DMA mode entirely.
http://sourceforge.net/mailarchive/message.php?msg_name=4A7C0594.2020208%40gmail.com
(Reported by Samuel Audet.)
In another report (by Jonathan Cameron), an FW643 works OK with two
cameras in dual buffer mode. Whether this is due to different chip
revisions or different usage patterns (different video formats) is not
yet clear. However, as far as the current capabilities of
firewire-core's isochronous I/O interface are concerned, simply
switching off dual-buffer on non-working and working FW643s alike is not
a problem in practice. We only need to revisit this issue if we are
going to enhance the interface, e.g. so that applications can explicitly
choose modes.
Reported-by: Samuel Audet <samuel.audet@gmail.com>
Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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This fixes a regression due to post 2.6.30 commit "firewire: core: do
not DMA-map stack addresses" 6fdc03709433ccc2005f0f593ae9d9dd04f7b485.
As David Moore noted, a previously correct sizeof() expression became
wrong since the commit changed its argument from an array to a pointer.
This resulted in an oops in ohci_cancel_packet in the shared workqueue
thread's context when an isochronous resource was to be freed.
Reported-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
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Bug introduced by mainline commit e7432675f8ca868a4af365759a8d4c3779a3d922
The bug causes ocfs2_write_begin_nolock() to oops when len=0.
Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Joel Becker <joel.becker@oracle.com>
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Fix some problems seen in the chunk size processing when activating a
pre-existing snapshot.
For a new snapshot, the chunk size can either be supplied by the creator
or a default value can be used. For an existing snapshot, the
chunk size in the snapshot header on disk should always be used.
If someone attempts to load an existing snapshot and has the 'default
chunk size' option set, the kernel uses its default value even when it
is incorrect for the snapshot being loaded. This patch ensures the
correct on-disk value is always used.
Secondly, when the code does use the chunk size stored on the disk it is
prudent to revalidate it, so the code can exit cleanly if it got
corrupted as happened in
https://bugzilla.redhat.com/show_bug.cgi?id=461506 .
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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Break the function set_chunk_size to two functions in preparation for
the fix in the following patch.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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If a persistent snapshot fills up, a race can corrupt the on-disk header
which causes a crash on any future attempt to activate the snapshot
(typically while booting). This patch fixes the race.
When the snapshot overflows, __invalidate_snapshot is called, which calls
snapshot store method drop_snapshot. It goes to persistent_drop_snapshot that
calls write_header. write_header constructs the new header in the "area"
location.
Concurrently, an existing kcopyd job may finish, call copy_callback
and commit_exception method, that goes to persistent_commit_exception.
persistent_commit_exception doesn't do locking, relying on the fact that
callbacks are single-threaded, but it can race with snapshot invalidation and
overwrite the header that is just being written while the snapshot is being
invalidated.
The result of this race is a corrupted header being written that can
lead to a crash on further reactivation (if chunk_size is zero in the
corrupted header).
The fix is to use separate memory areas for each.
See the bug: https://bugzilla.redhat.com/show_bug.cgi?id=461506
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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Refactor chunk_io to prepare for the fix in the following patch.
Pass an area pointer to chunk_io and simplify zero_disk_area to use
chunk_io. No functional change.
Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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Device-mapper userspace logs (like the clustered log) are
identified by a universally unique identifier (UUID). This
identifier is used to associate requests from the kernel to
a specific log in userspace. The UUID must be unique everywhere,
since multiple machines may use this identifier when communicating
about a particular log, as is the case for cluster logs.
Sometimes, device-mapper/LVM may re-use a UUID. This is the
case during pvmoves, when moving from one segment of an LV
to another, or when resizing a mirror, etc. In these cases,
a new log is created with the same UUID and loaded in the
"inactive" slot. When a device-mapper "resume" is issued,
the "live" table is deactivated and the new "inactive" table
becomes "live". (The "inactive" table can also be removed
via a device-mapper 'clear' command.)
The above two issues were colliding. More than one log was being
created with the same UUID, and there was no way to distinguish
between them. So, sometimes the wrong log would be swapped
out during the exchange.
The solution is to create a locally unique identifier,
'luid', to go along with the UUID. This new identifier is used
to determine exactly which log is being referenced by the kernel
when the log exchange is made. The identifier is not
universally safe, but it does not need to be, since
create/destroy/suspend/resume operations are bound to a specific
machine; and these are the operations that make up the exchange.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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This patch fixes a bug which was triggering a case where the primary leg
could not be changed on failure even when the mirror was in-sync.
The case involves the failure of the primary device along with
the transient failure of the log device. The problem is that
bios can be put on the 'failures' list (due to log failure)
before 'fail_mirror' is called due to the primary device failure.
Normally, this is fine, but if the log device failure is transient,
a subsequent iteration of the work thread, 'do_mirror', will
reset 'log_failure'. The 'do_failures' function then resets
the 'in_sync' variable when processing bios on the failures list.
The 'in_sync' variable is what is used to determine if the
primary device can be switched in the event of a failure. Since
this has been reset, the primary device is incorrectly assumed
to be not switchable.
The case has been seen in the cluster mirror context, where one
machine realizes the log device is dead before the other machines.
As the responsibilities of the server migrate from one node to
another (because the mirror is being reconfigured due to the failure),
the new server may think for a moment that the log device is fine -
thus resetting the 'log_failure' variable.
In any case, it is inappropiate for us to reset the 'log_failure'
variable. The above bug simply illustrates that it can actually
hurt us.
Cc: stable@kernel.org
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
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Linus Torvalds
Ed Cashin
Zhenyu Wang
Dave Airlie
Mimi Zohar
David S. Miller
Roderick Colenbrander
Nicolas Pitre
Oleg Nesterov
Mel Gorman
David Howells
Stefan Richter
Sunil Mushran
Mikulas Patocka
Jonathan Brassow