Steven Rostedt [Sat, 12 Sep 2009 23:26:21 +0000 (19:26 -0400)]
tracing: use the new trace_entries.h to create format files
This patch changes the way the format files in
debugfs/tracing/events/ftrace/*/format
are created. It uses the new trace_entries.h file to automate the
creation of the format files to ensure that they are always in sync
with the actual structures. This is the same methodology used to
create the format files for the TRACE_EVENT macro.
This also updates the filter creation that was built on the creation
of the format files.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Sat, 12 Sep 2009 23:22:23 +0000 (19:22 -0400)]
tracing: show details of structures within the ftrace structures
Some of the internal ftrace structures use structures within. The
output of a field saying it is just a structure is useless for a format
file. A binary reader of the ring buffer needs to know more about
how the fields are broken up.
This patch adds to the ftrace structure macros new fields to
describe the structures inside a structure.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Sat, 12 Sep 2009 23:17:15 +0000 (19:17 -0400)]
tracing: use macros to create internal ftrace entry ring buffer structures
The entries used by ftrace internal code (plugins) currently have their
formats manually exported to userspace. That is, the format files in
debugfs/tracing/events/ftrace/*/format are currently created by hand.
This is a maintenance nightmare, and can easily become out of sync
with what is actually shown.
This patch uses the methodology of the TRACE_EVENT macros to build
the structures so that their formats can be automated and this
will keep the structures in sync with what users can see.
This patch only changes the way the structures are created. Further
patches will build off of this to automate the format files.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Tom Zanussi [Fri, 11 Sep 2009 04:13:51 +0000 (23:13 -0500)]
tracing/filters: add filter Documentation
Documentation for event filters and formats.
v2 changes: fix a few problems noticed by Randy Dunlap.
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <1252642431.8016.9.camel@tropicana> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Only 24 bytes needs to be reserved on the stack for the function graph
tracer on x86_64.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <20090729085837.GB4998@jolsa.lab.eng.brq.redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
John Reiser [Mon, 27 Jul 2009 18:23:50 +0000 (11:23 -0700)]
ftrace: __start_mcount_loc should be .init.rodata
__start_mcount_loc[] is unused after init, yet occupies RAM forever
as part of .rodata. 152kiB is typical on a 64-bit architecture. Instead,
__start_mcount_loc should be in the interval [__init_begin, __init_end)
so that the space is reclaimed after init.
__start_mcount_loc[] is generated during the load portion
of kernel build, and is used only by ftrace_init(). ftrace_init is declared
'__init' and is in .init.text, which is freed after init.
__start_mcount_loc is placed into .rodata by a call to MCOUNT_REC inside
the RO_DATA macro of include/asm-generic/vmlinux.lds.h. The array *is*
read-only, but more importantly it is not used after init. So the call to
MCOUNT_REC should be moved from RO_DATA to INIT_DATA.
This patch has been tested on x86_64 with CONFIG_DEBUG_PAGEALLOC=y
which verifies that the address range never is accessed after init.
Signed-off-by: John Reiser <jreiser@BitWagon.com>
LKML-Reference: <4A6DF0B6.7080402@bitwagon.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: do not update tracing_max_latency when tracer is stopped
The state of the function pair tracing_stop()/tracing_start() is
correctly considered when tracer data are updated. However, the global
and externally accessible variable tracing_max_latency is always updated
- even when tracing is stopped.
The update should only occur, if tracing was not stopped.
Signed-off-by: Carsten Emde <C.Emde@osadl.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: remove unused local variables in tracer probe functions
When the nsecs_to_usecs() conversion in probe_wakeup_sched_switch() and
check_critical_timing() was moved to a later stage in order to avoid
unnecessary computing, it was overlooked to remove the original
variables, assignments and comments..
Signed-off-by: Carsten Emde <C.Emde@osadl.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: prevent NULL pointer dereference in ftrace_raw_event_block_bio_bounce
Booting 2.6.31 and executing
echo 1 >/sys/kernel/debug/tracing/events/enable
leads to
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<c032a583>] ftrace_raw_event_block_bio_bounce+0x4b/0xb9
Apparently,
bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask);
is called in block/blk-map.c:58 where bio->bi_bdev in set to NULL and
still is NULL when an attempt is made to evaluate bio->bi_bdev->bd_dev
in include/trace/events/block.h:189.
The tracepoint should ensure bio->bi_bdev is not dereferenced, if NULL.
Signed-off-by: Carsten Emde <C.Emde@osadl.org>
LKML-Reference: <4AAAC9B1.9060505@osadl.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
tracing: trace parser support for function and graph
Convert the writing to 'set_graph_function', 'set_ftrace_filter'
and 'set_ftrace_notrace' to use the generic trace_parser
'trace_get_user' function.
Removed FTRACE_ITER_CONT flag, since it's not needed after this change.
Minor fix in set_graph_function display - g_show function.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1252682969-3366-4-git-send-email-jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Convert the parsing of the file 'set_event' to use the generic
trace_praser 'trace_get_user' function.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1252682969-3366-3-git-send-email-jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Create a "trace_parser" that can parse the user space input for
separate words.
struct trace_parser is the descriptor.
Generic "trace_get_user" function that can be a helper to read multiple
words passed in by user space.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
LKML-Reference: <1252682969-3366-2-git-send-email-jolsa@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Fri, 11 Sep 2009 18:24:13 +0000 (14:24 -0400)]
tracing: consolidate code between trace_output.c and trace_function_graph.c
Both trace_output.c and trace_function_graph.c do basically the same
thing to handle the printing of the latency-format. This patch moves
the code into one function that both can use.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Fri, 11 Sep 2009 17:55:35 +0000 (13:55 -0400)]
tracing: add lock depth to entries
This patch adds the lock depth of the big kernel lock to the generic
entry header. This way we can see the depth of the lock and help
in removing the BKL.
Steven Rostedt [Fri, 11 Sep 2009 15:36:23 +0000 (11:36 -0400)]
tracing: move tgid out of generic entry and into userstack
The userstack trace required the recording of the tgid entry.
Unfortunately, it was added to the generic entry where it wasted
4 bytes of every entry and was only used by one entry.
This patch moves it out of the generic field and moves it into the
only user (userstack_entry).
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Fri, 11 Sep 2009 04:30:26 +0000 (00:30 -0400)]
tracing: add latency format to function_graph tracer
While debugging something with the function_graph tracer, I found the
need to see the preempt count of the traces. Unfortunately, since
the function graph tracer has its own output formatting, it does not
honor the latency-format option.
This patch makes the function_graph tracer honor the latency-format
option, but still keeps control of the output. But now we have the
same details that the latency-format supplies.
Steven Rostedt [Thu, 10 Sep 2009 21:22:44 +0000 (17:22 -0400)]
x86/tracing: comment need for atomic nop
The dynamic function tracer relys on the macro P6_NOP5 always being
an atomic NOP. If for some reason it is changed to be two operations
(like a nop2 nop3) it can faults within the kernel when the function
tracer modifies the code.
This patch adds a comment to note that the P6_NOPs are expected to
be atomic. This will hopefully prevent anyone from changing that.
Reported-by: Mathieu Desnoyer <mathieu.desnoyers@polymtl.ca> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Wed, 9 Sep 2009 14:36:01 +0000 (10:36 -0400)]
tracing: do not grab lock in wakeup latency function tracing
The wakeup tracer, when enabled, has its own function tracer.
It only traces the functions on the CPU where the task it is following
is on. If a task is woken on one CPU but then migrates to another CPU
before it wakes up, the latency tracer will then start tracing functions
on the other CPU.
To find which CPU the task is on, the wakeup function tracer performs
a task_cpu(wakeup_task). But to make sure the task does not disappear
it grabs the wakeup_lock, which is also taken when the task wakes up.
By taking this lock, the function tracer does not need to worry about
the task being freed as it checks its cpu.
Jan Blunck found a problem with this approach on his 32 CPU box. When
a task is being traced by the wakeup tracer, all functions take this
lock. That means that on all 32 CPUs, each function call is taking
this one lock to see if the task is on that CPU. This lock has just
serialized all functions on all 32 CPUs. Needless to say, this caused
major issues on that box. It would even lockup.
This patch changes the wakeup latency to insert a probe on the migrate task
tracepoint. When a task changes its CPU that it will run on, the
probe will take note. Now the wakeup function tracer no longer needs
to take the lock. It only compares the current CPU with a variable that
holds the current CPU the task is on. We don't worry about races since
it is OK to add or miss a function trace.
Reported-by: Jan Blunck <jblunck@suse.de> Tested-by: Jan Blunck <jblunck@suse.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Robert Richter [Fri, 31 Jul 2009 12:58:04 +0000 (14:58 +0200)]
ring-buffer: consolidate interface of rb_buffer_peek()
rb_buffer_peek() operates with struct ring_buffer_per_cpu *cpu_buffer
only. Thus, instead of passing variables buffer and cpu it is better
to use cpu_buffer directly. This also reduces the risk of races since
cpu_buffer is not calculated twice.
Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1249045084-3028-1-git-send-email-robert.richter@amd.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
powerpc: Fix i8259 interrupt driver kernel crash on ML510
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>
* 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
* 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.
Nicolas Pitre [Sat, 5 Sep 2009 04:25:37 +0000 (00:25 -0400)]
ext2: fix unbalanced kmap()/kunmap()
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.
Merge branch 'upstream-linus' of 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.
pty: don't limit the writes to 'pty_space()' inside 'pty_write()'
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>
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.
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>
page-allocator: always change pageblock ownership when anti-fragmentation is 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>
David Howells [Sat, 5 Sep 2009 18:17:07 +0000 (11:17 -0700)]
nommu: fix error handling in do_mmap_pgoff()
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>
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>
Stefan Richter [Thu, 3 Sep 2009 21:07:35 +0000 (23:07 +0200)]
firewire: sbp2: fix freeing of unallocated memory
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>
Stefan Richter [Fri, 28 Aug 2009 11:26:03 +0000 (13:26 +0200)]
firewire: ohci: fix Ricoh R5C832, video reception
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>
Stefan Richter [Fri, 28 Aug 2009 11:25:15 +0000 (13:25 +0200)]
firewire: ohci: fix Agere FW643 and multiple cameras
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>
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>
Steven Rostedt [Fri, 4 Sep 2009 18:24:40 +0000 (14:24 -0400)]
ring-buffer: only enable ring_buffer_swap_cpu when needed
Since the ability to swap the cpu buffers adds a small overhead to
the recording of a trace, we only want to add it when needed.
Only the irqsoff and preemptoff tracers use this feature, and both are
not recommended for production kernels. This patch disables its use
when neither irqsoff nor preemptoff is configured.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Fri, 4 Sep 2009 18:11:34 +0000 (14:11 -0400)]
ring-buffer: check for swapped buffers in start of committing
Because the irqsoff tracer can swap an internal CPU buffer, it is possible
that a swap happens between the start of the write and before the committing
bit is set (the committing bit will disable swapping).
This patch adds a check for this and will fail the write if it detects it.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Thu, 3 Sep 2009 23:13:05 +0000 (19:13 -0400)]
tracing: report error in trace if we fail to swap latency buffer
The irqsoff tracer will fail to swap the cpu buffer with the max
buffer if it preempts a commit. Instead of ignoring this, this patch
makes the tracer report it if the last max latency failed due to preempting
a current commit.
The output of the latency tracer will look like this:
Steven Rostedt [Wed, 2 Sep 2009 18:17:06 +0000 (14:17 -0400)]
tracing: pass around ring buffer instead of tracer
The latency tracers (irqsoff and wakeup) can swap trace buffers
on the fly. If an event is happening and has reserved data on one of
the buffers, and the latency tracer swaps the global buffer with the
max buffer, the result is that the event may commit the data to the
wrong buffer.
This patch changes the API to the trace recording to be recieve the
buffer that was used to reserve a commit. Then this buffer can be passed
in to the commit.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Tue, 1 Sep 2009 15:06:29 +0000 (11:06 -0400)]
tracing: use timestamp to determine start of latency traces
Currently the latency tracers reset the ring buffer. Unfortunately
if a commit is in process (due to a trace event), this can corrupt
the ring buffer. When this happens, the ring buffer will detect
the corruption and then permanently disable the ring buffer.
The bug does not crash the system, but it does prevent further tracing
after the bug is hit.
Instead of reseting the trace buffers, the timestamp of the start of
the trace is used instead. The buffers will still contain the previous
data, but the output will not count any data that is before the
timestamp of the trace.
Note, this only affects the static trace output (trace) and not the
runtime trace output (trace_pipe). The runtime trace output does not
make sense for the latency tracers anyway.
Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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 .
dm snapshot: fix header corruption race on invalidation
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
dm log: userspace add luid to distinguish between concurrent log instances
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>
dm raid1: do not allow log_failure variable to unset after being set
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>
dm log: remove incorrect field from userspace table output
The output of 'dmsetup table' includes an internal field that should not
be there. This patch removes it. To make the fix simpler, we first
reorder a constructor argument
The 'device size' argument is generated internally. Currently it is
placed as the last space-separated word of the constructor string.
However, we need to use a version of the string without this word, so we
move it to the beginning instead so it is trivial to skip past it.
We keep a copy of the arguments passed to userspace for creating a log,
just in case we need to resend them. These are the same arguments that
are desired in the STATUSTYPE_TABLE request, except for one. When
creating the userspace log, the userspace daemon must know the size of
the mirror, so that is added to the arguments given in the constructor
table. We were printing this extra argument out as well, which is a
mistake.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Mike Snitzer [Fri, 4 Sep 2009 19:40:25 +0000 (20:40 +0100)]
dm stripe: expose correct io hints
Set sensible I/O hints for striped DM devices in the topology
infrastructure added for 2.6.31 for userspace tools to
obtain via sysfs.
Add .io_hints to 'struct target_type' to allow the I/O hints portion
(io_min and io_opt) of the 'struct queue_limits' to be set by each
target and implement this for dm-stripe.
Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Mike Snitzer [Fri, 4 Sep 2009 19:40:24 +0000 (20:40 +0100)]
dm table: add more context to terse warning messages
A couple of recent warning messages make it difficult for the reader to
determine exactly what is wrong. This patch adds more information to
those messages.
The logic to check for valid device areas is inverted relative to proper
use with iterate_devices.
The iterate_devices method calls its callback for every underlying
device in the target. If any callback returns non-zero, iterate_devices
exits immediately. But the callback device_area_is_valid() returns 0 on
error and 1 on success. The overall effect without is that an error is
issued only if every device is invalid.
This patch renames device_area_is_valid to device_area_is_invalid and
inverts the logic so that one invalid device is sufficient to raise
an error.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Mike Snitzer [Fri, 4 Sep 2009 19:40:19 +0000 (20:40 +0100)]
dm snapshot: implement iterate devices
Implement the .iterate_devices for the origin and snapshot targets.
dm-snapshot's lack of .iterate_devices resulted in the inability to
properly establish queue_limits for both targets.
With 4K sector drives: an unfortunate side-effect of not establishing
proper limits in either targets' DM device was that IO to the devices
would fail even though both had been created without error.
Commit af4874e03ed82f050d5872d8c39ce64bf16b5c38 ("dm target:s introduce
iterate devices fn") in 2.6.31-rc1 should have implemented .iterate_devices
for dm-snap.c's origin and snapshot targets.
Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
If map_request() calls dm_kill_unmapped_request() to complete a cloned
bio without dispatching it, clone->bio is still set when
dm_end_request() is called and the BUG_ON(clone->bio) is incorrect.
The patch fixes this bug by freeing bio in dm_end_request() if the clone
has bio. I've redone my tests to cover all I/O paths and confirmed
there's no other regression.
Here is the oops I hit in request-based dm when I do I/O to a multipath
device which doesn't have any active path nor queue_if_no_path setting:
Steven Rostedt [Fri, 4 Sep 2009 16:12:39 +0000 (12:12 -0400)]
tracing: remove users of tracing_reset
The function tracing_reset is deprecated for outside use of trace.c.
The new function to reset the the buffers is tracing_reset_online_cpus.
The reason for this is that resetting the buffers while the event
trace points are active can corrupt the buffers, because they may
be writing at the time of reset. The tracing_reset_online_cpus disables
writes and waits for current writers to finish.
This patch replaces all users of tracing_reset except for the latency
tracers. Those changes require more work and will be removed in the
following patches.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Tue, 1 Sep 2009 02:32:27 +0000 (22:32 -0400)]
tracing: disable update max tracer while reading trace
When reading the tracer from the trace file, updating the max latency
may corrupt the output. This patch disables the tracing of the max
latency while reading the trace file.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Wed, 2 Sep 2009 16:27:41 +0000 (12:27 -0400)]
tracing: print out start and stop in latency traces
During development of the tracer, we would copy information from
the live tracer to the max tracer with one memcpy. Since then we
added a generic ring buffer and we handle the copies differently now.
Unfortunately, we never copied the critical section information, and
we lost the output:
# => started at: kmem_cache_alloc
# => ended at: kmem_cache_alloc
This patch adds back the critical start and end copying as well as
removes the unused "trace_idx" and "overrun" fields of the
trace_array_cpu structure.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Thu, 3 Sep 2009 23:53:46 +0000 (19:53 -0400)]
ring-buffer: disable all cpu buffers when one finds a problem
Currently the way RB_WARN_ON works, is to disable either the current
CPU buffer or all CPU buffers, depending on whether a ring_buffer or
ring_buffer_per_cpu struct was passed into the macro.
Most users of the RB_WARN_ON pass in the CPU buffer, so only the one
CPU buffer gets disabled but the rest are still active. This may
confuse users even though a warning is sent to the console.
This patch changes the macro to disable the entire buffer even if
the CPU buffer is passed in.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Thu, 3 Sep 2009 14:23:58 +0000 (10:23 -0400)]
ring-buffer: do not count discarded events
The latency tracers report the number of items in the trace buffer.
This uses the ring buffer data to calculate this. Because discarded
events are also counted, the numbers do not match the number of items
that are printed. The ring buffer also adds a "padding" item to the
end of each buffer page which also gets counted as a discarded item.
This patch decrements the counter to the page entries on a discard.
This allows us to ignore discarded entries while reading the buffer.
Decrementing the counter is still safe since it can only happen while
the committing flag is still set.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Thu, 3 Sep 2009 19:33:41 +0000 (15:33 -0400)]
ring-buffer: remove ring_buffer_event_discard
The function ring_buffer_event_discard can be used on any item in the
ring buffer, even after the item was committed. This function provides
no safety nets and is very race prone.
An item may be safely removed from the ring buffer before it is committed
with the ring_buffer_discard_commit.
Since there are currently no users of this function, and because this
function is racey and error prone, this patch removes it altogether.
Note, removing this function also allows the counters to ignore
all discarded events (patches will follow).
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Thu, 3 Sep 2009 14:02:09 +0000 (10:02 -0400)]
ring-buffer: fix ring_buffer_read crossing pages
When the ring buffer uses an iterator (static read mode, not on the
fly reading), when it crosses a page boundery, it will skip the first
entry on the next page. The reason is that the last entry of a page
is usually padding if the page is not full. The padding will not be
returned to the user.
The problem arises on ring_buffer_read because it also increments the
iterator. Because both the read and peek use the same rb_iter_peek,
the rb_iter_peak will return the padding but also increment to the next
item. This is because the ring_buffer_peek will not incerment it
itself.
The ring_buffer_read will increment it again and then call rb_iter_peek
again to get the next item. But that will be the second item, not the
first one on the page.
The reason this never showed up before, is because the ftrace utility
always calls ring_buffer_peek first and only uses ring_buffer_read
to increment to the next item. The ring_buffer_peek will always keep
the pointer to a valid item and not padding. This just hid the bug.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt [Thu, 3 Sep 2009 14:12:13 +0000 (10:12 -0400)]
ring-buffer: remove unnecessary cpu_relax
The loops in the ring buffer that use cpu_relax are not dependent on
other CPUs. They simply came across some padding in the ring buffer and
are skipping over them. It is a normal loop and does not require a
cpu_relax.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
David S. Miller [Fri, 4 Sep 2009 10:38:54 +0000 (03:38 -0700)]
sparc64: Fix bootup with mcount in some configs.
Functions invoked early when booting up a cpu can't use
tracing because mcount requires a valid 'current_thread_info()'
and TLB mappings to be setup.
The code path of sun4v_register_mondo_queues --> register_one_mondo
is one such case. sun4v_register_mondo_queues already has the
necessary 'notrace' annotation, but register_one_mondo does not.
Normally register_one_mondo is inlined so the bug doesn't trigger,
but with some config/compiler combinations, it won't be so we
must properly mark it notrace.
While we're here, add 'notrace' annoations to prom_printf and
prom_halt so that early error handling won't have the same problem.
Reported-by: Alexander Beregalov <a.beregalov@gmail.com> Reported-by: Leif Sawyer <lsawyer@gci.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Compaq Presario R4000-series laptops are not sending a "volume up button
release" and "volume down button release" signal in the PS/2 protocol for
atkbd. The URL below has some of confirmed reports:
Eric Dumazet [Thu, 3 Sep 2009 19:38:59 +0000 (22:38 +0300)]
slub: Fix kmem_cache_destroy() with SLAB_DESTROY_BY_RCU
kmem_cache_destroy() should call rcu_barrier() *after* kmem_cache_close() and
*before* sysfs_slab_remove() or risk rcu_free_slab() being called after
kmem_cache is deleted (kfreed).
rmmod nf_conntrack can crash the machine because it has to kmem_cache_destroy()
a SLAB_DESTROY_BY_RCU enabled cache.
Cc: <stable@kernel.org> Reported-by: Zdenek Kabelac <zdenek.kabelac@gmail.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
The function jffs2_nor_wbuf_flash_setup() doesn't allocate the verify buffer
if CONFIG_JFFS2_FS_WBUF_VERIFY is defined, so causing a kernel panic when
that macro is enabled and the verify function is called. Similarly the
jffs2_nor_wbuf_flash_cleanup() must free the buffer if
CONFIG_JFFS2_FS_WBUF_VERIFY is enabled.
The following patch fixes the problem.
The following patch applies to 2.6.30 kernel.
Arithmetic conversion in the mask computation makes the upper word
of the second argument passed down to mtd->read_oob(), be always 0
(assuming 'offs' being a 64-bit signed long long type, and
'mtd->writesize' being a 32-bit unsigned int type).
This patch applies over the other one adding masking in nftl_write,
"nftl: write support is broken".
Signed-off-by: Dimitri Gorokhovik <dimitri.gorokhovik@free.fr> Cc: Tim Gardner <tim.gardner@canonical.com> Cc: Scott James Remnant <scott@canonical.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: <dimitri.gorokhovik@free.fr> Cc: Tim Gardner <tim.gardner@canonical.com> Cc: Scott James Remnant <scott@canonical.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com> Cc: David Brownell <david-b@pacbell.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
projects / linux-beck.git / log