aboutsummaryrefslogtreecommitdiff
path: root/kernel
AgeCommit message (Collapse)Author
2009-09-06Merge branch 'tracing/core' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into tracing/core
2009-09-06Merge commit 'v2.6.31-rc9' into tracing/coreIngo Molnar
Merge reason: move from -rc5 to -rc9. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-05Merge branch 'perfcounters-fixes-for-linus' of ↵Linus Torvalds
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
2009-09-04ring-buffer: only enable ring_buffer_swap_cpu when neededSteven Rostedt
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>
2009-09-04ring-buffer: check for swapped buffers in start of committingSteven Rostedt
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>
2009-09-04tracing: report error in trace if we fail to swap latency bufferSteven Rostedt
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: # tracer: irqsoff # # irqsoff latency trace v1.1.5 on 2.6.31-rc5 # -------------------------------------------------------------------- # latency: 112 us, #1/1, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4) # ----------------- # | task: -4281 (uid:0 nice:0 policy:0 rt_prio:0) # ----------------- # => started at: save_args # => ended at: __do_softirq # # # _------=> CPU# # / _-----=> irqs-off # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / # ||||| delay # cmd pid ||||| time | caller # \ / ||||| \ | / bash-4281 1d.s6 265us : update_max_tr_single: Failed to swap buffers due to commit in progress Note the latency time and the functions that disabled the irqs or preemption will still be listed. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: add trace_array_printk for internal tracers to useSteven Rostedt
This patch adds a trace_array_printk to allow a tracer to use the trace_printk on its own trace array. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: pass around ring buffer instead of tracerSteven Rostedt
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>
2009-09-04tracing: make tracing_reset safe for external useSteven Rostedt
Reseting the trace buffer without first disabling the buffer and waiting for any writers to complete, can corrupt the ring buffer. This patch makes the external version of tracing_reset safe from corruption by disabling the ring buffer and calling synchronize_sched. This version can no longer be called from interrupt context. But all those callers have been removed. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: use timestamp to determine start of latency tracesSteven Rostedt
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>
2009-09-04tracing/filters: Defer pred allocation, fix memory leakLi Zefan
The predicates of an event and their filter structure are allocated when we create an event filter for the first time. These objects must be created once but each time we come with a new filter, we overwrite such pre-existing allocation, if any. Thus, this patch checks if the filter has already been allocated before going ahead. Spotted-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Masami Hiramatsu <mhiramat@redhat.com> LKML-Reference: <4A9CB1BA.3060402@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-09-04tracing: remove users of tracing_resetSteven Rostedt
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>
2009-09-04tracing: disable buffers and synchronize_sched before resettingSteven Rostedt
Resetting the ring buffers while traces are happening can corrupt the ring buffer and disable it (no kernel crash to worry about). The safest thing to do is disable the ring buffers, call synchronize_sched() to wait for all current writers to finish and then reset the buffer. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04tracing: disable update max tracer while reading traceSteven Rostedt
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>
2009-09-04tracing: print out start and stop in latency tracesSteven Rostedt
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>
2009-09-04ring-buffer: disable all cpu buffers when one finds a problemSteven Rostedt
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>
2009-09-04ring-buffer: do not count discarded eventsSteven Rostedt
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>
2009-09-04ring-buffer: remove ring_buffer_event_discardSteven Rostedt
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>
2009-09-04ring-buffer: fix ring_buffer_read crossing pagesSteven Rostedt
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>
2009-09-04ring-buffer: remove unnecessary cpu_relaxSteven Rostedt
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>
2009-09-04ring-buffer: do not swap buffers during a commitSteven Rostedt
If a commit is taking place on a CPU ring buffer, do not allow it to be swapped. Return -EBUSY when this is detected instead. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-09-04ring-buffer: do not reset while in a commitSteven Rostedt
The callers of reset must ensure that no commit can be taking place at the time of the reset. If it does then we may corrupt the ring buffer. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-08-31tracing/filters: Defer pred allocationLi Zefan
init_preds() allocates about 5392 bytes of memory (on x86_32) for a TRACE_EVENT. With my config, at system boot total memory occupied is: 5392 * (642 + 15) == 3459KB 642 == cat available_events | wc -l 15 == number of dirs in events/ftrace That's quite a lot, so we'd better defer memory allocation util it's needed, that's when filter is used. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Masami Hiramatsu <mhiramat@redhat.com> LKML-Reference: <4A9B8EA5.6020700@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-29perf_counter: Fix /0 bug in swcountersPeter Zijlstra
We have a race in the swcounter stuff where we can start counting a counter that has never been enabled, this leads to a /0 situation. The below avoids the /0 but doesn't close the race, this would need a new counter state. The race is due to perf_swcounter_is_counting() which cannot discern between disabled due to scheduled out, and disabled for any other reason. Such a crash has been seen by Ingo: [ 967.092372] divide error: 0000 [#1] SMP [ 967.096499] last sysfs file: /sys/devices/system/cpu/cpu15/cache/index2/shared_cpu_map [ 967.104846] CPU 5 [ 967.106965] Modules linked in: [ 967.110169] Pid: 3351, comm: hackbench Not tainted 2.6.31-rc8-tip-01158-gd940a54-dirty #1568 X8DTN [ 967.119456] RIP: 0010:[<ffffffff810c0aba>] [<ffffffff810c0aba>] perf_swcounter_ctx_event+0x127/0x1af [ 967.129137] RSP: 0018:ffff8801a95abd70 EFLAGS: 00010046 [ 967.134699] RAX: 0000000000000002 RBX: ffff8801bd645c00 RCX: 0000000000000002 [ 967.142162] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8801bd645d40 [ 967.149584] RBP: ffff8801a95abdb0 R08: 0000000000000001 R09: ffff8801a95abe00 [ 967.157042] R10: 0000000000000037 R11: ffff8801aa1245f8 R12: ffff8801a95abe00 [ 967.164481] R13: ffff8801a95abe00 R14: ffff8801aa1c0e78 R15: 0000000000000001 [ 967.171953] FS: 0000000000000000(0000) GS:ffffc90000a00000(0063) knlGS:00000000f7f486c0 [ 967.180406] CS: 0010 DS: 002b ES: 002b CR0: 000000008005003b [ 967.186374] CR2: 000000004822c0ac CR3: 00000001b19a2000 CR4: 00000000000006e0 [ 967.193770] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 967.201224] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 967.208692] Process hackbench (pid: 3351, threadinfo ffff8801a95aa000, task ffff8801a96b0000) [ 967.217607] Stack: [ 967.219711] 0000000000000000 0000000000000037 0000000200000001 ffffc90000a1107c [ 967.227296] <0> ffff8801a95abe00 0000000000000001 0000000000000001 0000000000000037 [ 967.235333] <0> ffff8801a95abdf0 ffffffff810c0c20 0000000200a14f30 ffff8801a95abe40 [ 967.243532] Call Trace: [ 967.246103] [<ffffffff810c0c20>] do_perf_swcounter_event+0xde/0xec [ 967.252635] [<ffffffff810c0ca7>] perf_tpcounter_event+0x79/0x7b [ 967.258957] [<ffffffff81037f73>] ftrace_profile_sched_switch+0xc0/0xcb [ 967.265791] [<ffffffff8155f22d>] schedule+0x429/0x4c4 [ 967.271156] [<ffffffff8100c01e>] int_careful+0xd/0x14 Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <1251472247.17617.74.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-29Merge branch 'tip/tracing/core' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/core
2009-08-28modules: Fix build error in the !CONFIG_KALLSYMS caseIngo Molnar
> James Bottomley (1): > module: workaround duplicate section names -tip testing found that this patch breaks the build on x86 if CONFIG_KALLSYMS is disabled: kernel/module.c: In function ‘load_module’: kernel/module.c:2367: error: ‘struct module’ has no member named ‘sect_attrs’ distcc[8269] ERROR: compile kernel/module.c on ph/32 failed make[1]: *** [kernel/module.o] Error 1 make: *** [kernel] Error 2 make: *** Waiting for unfinished jobs.... Commit 1b364bf misses the fact that section attributes are only built and dealt with if kallsyms is enabled. The patch below fixes this. ( note, technically speaking this should depend on CONFIG_SYSFS as well but this patch is correct too and keeps the #ifdef less intrusive - in the KALLSYMS && !SYSFS case the code is a NOP. ) Signed-off-by: Ingo Molnar <mingo@elte.hu> [ Replaced patch with a slightly cleaner variation by James Bottomley ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-28perf_counters: Increase paranoia levelIngo Molnar
Per-cpu counters are an ASLR information leak as they show the execution other tasks do. Increase the paranoia level to 1, which disallows per-cpu counters. (they still allow counting/profiling of own tasks - and admin can profile everything.) Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-27tracing: only show tracing_max_latency when latency tracer configuredSteven Rostedt
The tracing_max_latency file should only be present when one of the latency tracers ({preempt|irqs}off, wakeup*) are enabled. This patch also removes tracing_thresh when latency tracers are not enabled, as well as compiles out code that is only used for latency tracers. Reported-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-08-27tracing: remove legacy select of MARKERS by context switch tracingSteven Rostedt
The context switch tracer was made before tracepoints were mature, and the original version used markers. This is no longer true and this patch removes the select. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-08-27module: workaround duplicate section namesJames Bottomley
The root cause is a duplicate section name (.text); is this legal? [ Amerigo Wang: "AFAIK, yes." ] However, there's a problem with commit 6d76013381ed28979cd122eb4b249a88b5e384fa in that if you fail to allocate a mod->sect_attrs (in this case it's null because of the duplication), it still gets used without checking in add_notes_attrs() This should fix it [ This patch leaves other problems, particularly the sections directory, but recent parisc toolchains seem to produce these modules and this prevents a crash and is a minimal change -- RR ] Signed-off-by: James Bottomley <James.Bottomley@suse.de> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Tested-by: Helge Deller <deller@gmx.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-27module: fix BUG_ON() for powerpc (and other function descriptor archs)Rusty Russell
The rarely-used symbol_put_addr() needs to use dereference_function_descriptor on powerpc. Reported-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-26clone(): fix race between copy_process() and de_thread()Oleg Nesterov
Spotted by Hiroshi Shimamoto who also provided the test-case below. copy_process() uses signal->count as a reference counter, but it is not. This test case #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #include <stdio.h> #include <errno.h> #include <pthread.h> void *null_thread(void *p) { for (;;) sleep(1); return NULL; } void *exec_thread(void *p) { execl("/bin/true", "/bin/true", NULL); return null_thread(p); } int main(int argc, char **argv) { for (;;) { pid_t pid; int ret, status; pid = fork(); if (pid < 0) break; if (!pid) { pthread_t tid; pthread_create(&tid, NULL, exec_thread, NULL); for (;;) pthread_create(&tid, NULL, null_thread, NULL); } do { ret = waitpid(pid, &status, 0); } while (ret == -1 && errno == EINTR); } return 0; } quickly creates an unkillable task. If copy_process(CLONE_THREAD) races with de_thread() copy_signal()->atomic(signal->count) breaks the signal->notify_count logic, and the execing thread can hang forever in kernel space. Change copy_process() to increment count/live only when we know for sure we can't fail. In this case the forked thread will take care of its reference to signal correctly. If copy_process() fails, check CLONE_THREAD flag. If it it set - do nothing, the counters were not changed and current belongs to the same thread group. If it is not set, ->signal must be released in any case (and ->count must be == 1), the forked child is the only thread in the thread group. We need more cleanups here, in particular signal->count should not be used by de_thread/__exit_signal at all. This patch only fixes the bug. Reported-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Tested-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-26tracing: Convert event tracing code to use NR_syscallsJason Baron
Convert the syscalls event tracing code to use NR_syscalls, instead of FTRACE_SYSCALL_MAX. NR_syscalls is standard accross most arches, and reduces code confusion/complexity. Signed-off-by: Jason Baron <jbaron@redhat.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jiaying Zhang <jiayingz@google.com> Cc: Martin Bligh <mbligh@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Josh Stone <jistone@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anwin <hpa@zytor.com> Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> LKML-Reference: <9b4f1a84ecae57cc6599412772efa36f0d2b815b.1251146513.git.jbaron@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-26tracing: Don't trace kernel thread syscallsHendrik Brueckner
Kernel threads don't call syscalls using the sysenter/sysexit path. Instead they directly call the sys_* or do_* functions that implement the syscalls inside the kernel. The current syscall tracepoints only bind the sysenter/sysexit path, then it has no effect to trace the kernel thread calls to syscalls in that path. Setting the TIF_SYSCALL_TRACEPOINT flag is then useless for these. Actually there is only one case when a kernel thread can reach the usual syscall exit tracing path: when we create a kernel thread, the child comes to ret_from_fork and is the fork() return is then traced. But this information alone is useless, then we don't want to set the TIF flags for these threads. Kernel threads have task_struct->mm set to NULL. (Thanks to Heiko for that hint ;-) The idea is then to check the mm field in syscall_regfunc() and set the flag accordingly. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jiaying Zhang <jiayingz@google.com> Cc: Martin Bligh <mbligh@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> LKML-Reference: <20090825160237.GG4639@cetus.boeblingen.de.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-26tracing: Check invalid syscall nr while tracing syscallsHendrik Brueckner
Most arch syscall_get_nr() implementations returns -1 if the syscall number is not valid. Accessing the bit field without a check might result in a kernel oops (at least I saw it on s390 for ftrace selftest). Before this change, this problem did not occur, because the invalid syscall number (-1) caused syscall_nr_to_meta() to return NULL. There are at least two scenarios where syscall_get_nr() can return -1: 1. For example, ptrace stores an invalid syscall number, and thus, tracing code resets it. (see do_syscall_trace_enter in arch/s390/kernel/ptrace.c) 2. The syscall_regfunc() (kernel/tracepoint.c) sets the TIF_SYSCALL_FTRACE (now: TIF_SYSCALL_TRACEPOINT) flag for all threads which include kernel threads. However, the ftrace selftest triggers a kernel oops when testing syscall trace points: - The kernel thread is started as ususal (do_fork()), - tracing code sets TIF_SYSCALL_FTRACE, - the ret_from_fork() function is triggered and starts ftrace_syscall_exit() with an invalid syscall number. To avoid these scenarios, I suggest to check the syscall_nr. For instance, the ftrace selftest fails for s390 (with config option CONFIG_FTRACE_SYSCALLS set) and produces the following kernel oops. Unable to handle kernel pointer dereference at virtual kernel address 2000000000 Oops: 0038 [#1] PREEMPT SMP Modules linked in: CPU: 0 Not tainted 2.6.31-rc6-next-20090819-dirty #18 Process kthreadd (pid: 818, task: 000000003ea207e8, ksp: 000000003e813eb8) Krnl PSW : 0704100180000000 00000000000ea54c (ftrace_syscall_exit+0x58/0xdc) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:1 PM:0 EA:3 Krnl GPRS: 0000000000000000 00000000000e0000 ffffffffffffffff 20000000008c2650 0000000000000007 0000000000000000 0000000000000000 0000000000000000 0000000000000000 0000000000000000 ffffffffffffffff 000000003e813d78 000000003e813f58 0000000000505ba8 000000003e813e18 000000003e813d78 Krnl Code: 00000000000ea540: e330d0000008 ag %r3,0(%r13) 00000000000ea546: a7480007 lhi %r4,7 00000000000ea54a: 1442 nr %r4,%r2 >00000000000ea54c: e31030000090 llgc %r1,0(%r3) 00000000000ea552: 5410d008 n %r1,8(%r13) 00000000000ea556: 8a104000 sra %r1,0(%r4) 00000000000ea55a: 5410d00c n %r1,12(%r13) 00000000000ea55e: 1211 ltr %r1,%r1 Call Trace: ([<0000000000000000>] 0x0) [<000000000001fa22>] do_syscall_trace_exit+0x132/0x18c [<000000000002d0c4>] sysc_return+0x0/0x8 [<000000000001c738>] kernel_thread_starter+0x0/0xc Last Breaking-Event-Address: [<00000000000ea51e>] ftrace_syscall_exit+0x2a/0xdc Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jiaying Zhang <jiayingz@google.com> Cc: Martin Bligh <mbligh@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> LKML-Reference: <20090825125027.GE4639@cetus.boeblingen.de.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-26Merge branch 'tracing/core' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into tracing/core Conflicts: include/linux/tracepoint.h Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-26ftrace: Move setting of clock-source out of optionsZhaolei
There are many clock sources for the tracing system but we can only enable/disable one at a time with the trace/options file. We can move the setting of clock-source out of options and add a separate file for it: # cat trace_clock [local] global # echo global > trace_clock # cat trace_clock local [global] Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> LKML-Reference: <4A939D08.6050604@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-08-26tracing/filters: Support filtering for char * stringsLi Zefan
Usually, char * entries are dangerous in traces because the string can be released whereas a pointer to it can still wait to be read from the ring buffer. But sometimes we can assume it's safe, like in case of RO data (eg: __file__ or __line__, used in bkl trace event). If these RO data are in a module and so is the call to the trace event, then it's safe, because the ring buffer will be flushed once this module get unloaded. To allow char * to be treated as a string: TRACE_EVENT(..., TP_STRUCT__entry( __field_ext(const char *, name, FILTER_PTR_STRING) ... ) ... ); The filtering will not dereference "char *" unless the developer explicitly sets FILTER_PTR_STR in __field_ext. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A7B9287.90205@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-08-26tracing/filters: Add __field_ext() to TRACE_EVENTLi Zefan
Add __field_ext(), so a field can be assigned to a specific filter_type, which matches a corresponding filter function. For example, a later patch will allow this: __field_ext(const char *, str, FILTER_PTR_STR); Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A7B9272.6050709@cn.fujitsu.com> [ Fixed a -1 to FILTER_OTHER Forward ported to latest kernel. ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-08-26tracing/filters: Add filter_type to struct ftrace_event_fieldLi Zefan
The type of a field is stored as a string in @type, and here we add @filter_type which is an enum value. This prepares for later patches, so we can specifically assign different @filter_type for the same @type. For example normally a "char *" field is treated as a ptr, but we may want it to be treated as a string when doing filting. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> LKML-Reference: <4A7B925E.9030605@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-08-26tracing: Create generic syscall TRACE_EVENTsJosh Stone
This converts the syscall_enter/exit tracepoints into TRACE_EVENTs, so you can have generic ftrace events that capture all system calls with arguments and return values. These generic events are also renamed to sys_enter/exit, so they're more closely aligned to the specific sys_enter_foo events. Signed-off-by: Josh Stone <jistone@redhat.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jiaying Zhang <jiayingz@google.com> Cc: Martin Bligh <mbligh@google.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> LKML-Reference: <1251150194-1713-5-git-send-email-jistone@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-26tracing: Move tracepoint callbacks from declaration to definitionJosh Stone
It's not strictly correct for the tracepoint reg/unreg callbacks to occur when a client is hooking up, because the actual tracepoint may not be present yet. This happens to be fine for syscall, since that's in the core kernel, but it would cause problems for tracepoints defined in a module that hasn't been loaded yet. It also means the reg/unreg has to be EXPORTed for any modules to use the tracepoint (as in SystemTap). This patch removes DECLARE_TRACE_WITH_CALLBACK, and instead introduces DEFINE_TRACE_FN which stores the callbacks in struct tracepoint. The callbacks are used now when the active state of the tracepoint changes in set_tracepoint & disable_tracepoint. This also introduces TRACE_EVENT_FN, so ftrace events can also provide registration callbacks if needed. Signed-off-by: Josh Stone <jistone@redhat.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jiaying Zhang <jiayingz@google.com> Cc: Martin Bligh <mbligh@google.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> LKML-Reference: <1251150194-1713-4-git-send-email-jistone@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-26tracing: Make syscall tracepoints conditionalJosh Stone
The syscall enter/exit tracepoints are only supported on archs that HAVE_SYSCALL_TRACEPOINTS, so the declarations should be #ifdef'ed. Also, the definition of syscall_regfunc and syscall_unregfunc should depend on this same config, rather than the ftrace-specific one. Signed-off-by: Josh Stone <jistone@redhat.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jiaying Zhang <jiayingz@google.com> Cc: Martin Bligh <mbligh@google.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <1251150194-1713-3-git-send-email-jistone@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-26tracing: Rename FTRACE_SYSCALLS for tracepointsJosh Stone
s/HAVE_FTRACE_SYSCALLS/HAVE_SYSCALL_TRACEPOINTS/g s/TIF_SYSCALL_FTRACE/TIF_SYSCALL_TRACEPOINT/g The syscall enter/exit tracing is no longer specific to just ftrace, so they now have names that reflect their tie to tracepoints instead. Signed-off-by: Josh Stone <jistone@redhat.com> Cc: Jason Baron <jbaron@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Jiaying Zhang <jiayingz@google.com> Cc: Martin Bligh <mbligh@google.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> LKML-Reference: <1251150194-1713-2-git-send-email-jistone@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2009-08-25Merge branch 'perfcounters-fixes-for-linus' of ↵Linus Torvalds
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: Fix typo in read() output generation perf tools: Check perf.data owner
2009-08-25Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: clockevent: Prevent dead lock on clockevents_lock timers: Drop write permission on /proc/timer_list
2009-08-25Merge branch 'tracing-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: tracing: Fix too large stack usage in do_one_initcall() tracing: handle broken names in ftrace filter ftrace: Unify effect of writing to trace_options and option/*
2009-08-25tracing: Eliminate code duplication in kernel/tracepoint.cAnirban Sinha
Signed-off-by: Anirban Sinha <asinha@zeugmasystems.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: "Oleg Nesterov" <oleg@tv-sign.ru> LKML-Reference: <DDFD17CC94A9BD49A82147DDF7D545C501EA9047@exchange.ZeugmaSystems.local> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-21perf_counter: Fix typo in read() output generationPeter Zijlstra
When you iterate a list, using the iterator is useful. Before: ID: 5 ID: 5 ID: 5 ID: 5 EVNT: 0x40088b scale: nan ID: 5 CNT: 1006252 ID: 6 CNT: 1011090 ID: 7 CNT: 1011196 ID: 8 CNT: 1011095 EVNT: 0x40088c scale: 1.000000 ID: 5 CNT: 2003065 ID: 6 CNT: 2011671 ID: 7 CNT: 2012620 ID: 8 CNT: 2013479 EVNT: 0x40088c scale: 1.000000 ID: 5 CNT: 3002390 ID: 6 CNT: 3015996 ID: 7 CNT: 3018019 ID: 8 CNT: 3020006 EVNT: 0x40088b scale: 1.000000 ID: 5 CNT: 4002406 ID: 6 CNT: 4021120 ID: 7 CNT: 4024241 ID: 8 CNT: 4027059 After: ID: 1 ID: 2 ID: 3 ID: 4 EVNT: 0x400889 scale: nan ID: 1 CNT: 1005270 ID: 2 CNT: 1009833 ID: 3 CNT: 1010065 ID: 4 CNT: 1010088 EVNT: 0x400898 scale: nan ID: 1 CNT: 2001531 ID: 2 CNT: 2022309 ID: 3 CNT: 2022470 ID: 4 CNT: 2022627 EVNT: 0x400888 scale: 0.489467 ID: 1 CNT: 3001261 ID: 2 CNT: 3027088 ID: 3 CNT: 3027941 ID: 4 CNT: 3028762 Reported-by: stephane eranian <eranian@googlemail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Corey J Ashford <cjashfor@us.ibm.com> Cc: perfmon2-devel <perfmon2-devel@lists.sourceforge.net> LKML-Reference: <1250867976.7538.73.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-20tracing/syscalls: Fix the output of syscalls with no argumentsLi Zefan
Before: # echo 1 > events/syscalls/sys_enter_sync/enable # cat events/syscalls/sys_enter_sync/format ... field:int nr; offset:12; size:4; print fmt: "# sync # cat trace ... sync-8950 [000] 2366.087670: sys_sync( After: # echo 1 > events/syscalls/sys_enter_sync/enable # cat events/syscalls/sys_enter_sync/format ... field:int nr; offset:12; size:4; print fmt: "" # sync # cat trace sync-2134 [001] 136.780735: sys_sync() Reported-by: Masami Hiramatsu <mhiramat@redhat.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jason Baron <jbaron@redhat.com> Cc: Masami Hiramatsu <mhiramat@redhat.com> LKML-Reference: <4A8D05AF.20103@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>