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2010-08-28Merge branch 'for-linus' of ↵Linus Torvalds
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: pxa27x_keypad - remove input_free_device() in pxa27x_keypad_remove() Input: mousedev - fix regression of inverting axes Input: uinput - add devname alias to allow module on-demand load Input: hil_kbd - fix compile error USB: drop tty argument from usb_serial_handle_sysrq_char() Input: sysrq - drop tty argument form handle_sysrq() Input: sysrq - drop tty argument from sysrq ops handlers
2010-08-26PM QoS: Fix inline documentation.Saravana Kannan
Fix the pm_qos_add_request() kerneldoc comment that doesn't reflect the behavior of the function after the last PM QoS update. Signed-off-by: Saravana Kannan <skannan@codeaurora.org> Acked-by: mark gross <markgross@thegnar.org> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-08-25Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf, x86, Pentium4: Clear the P4_CCCR_FORCE_OVF flag tracing/trace_stack: Fix stack trace on ppc64
2010-08-25Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states sched: Fix rq->clock synchronization when migrating tasks
2010-08-25tracing/trace_stack: Fix stack trace on ppc64Anton Blanchard
save_stack_trace() stores the instruction pointer, not the function descriptor. On ppc64 the trace stack code currently dereferences the instruction pointer and shows 8 bytes of instructions in our backtraces: # cat /sys/kernel/debug/tracing/stack_trace Depth Size Location (26 entries) ----- ---- -------- 0) 5424 112 0x6000000048000004 1) 5312 160 0x60000000ebad01b0 2) 5152 160 0x2c23000041c20030 3) 4992 240 0x600000007c781b79 4) 4752 160 0xe84100284800000c 5) 4592 192 0x600000002fa30000 6) 4400 256 0x7f1800347b7407e0 7) 4144 208 0xe89f0108f87f0070 8) 3936 272 0xe84100282fa30000 Since we aren't dealing with function descriptors, use %pS instead of %pF to fix it: # cat /sys/kernel/debug/tracing/stack_trace Depth Size Location (26 entries) ----- ---- -------- 0) 5424 112 ftrace_call+0x4/0x8 1) 5312 160 .current_io_context+0x28/0x74 2) 5152 160 .get_io_context+0x48/0xa0 3) 4992 240 .cfq_set_request+0x94/0x4c4 4) 4752 160 .elv_set_request+0x60/0x84 5) 4592 192 .get_request+0x2d4/0x468 6) 4400 256 .get_request_wait+0x7c/0x258 7) 4144 208 .__make_request+0x49c/0x610 8) 3936 272 .generic_make_request+0x390/0x434 Signed-off-by: Anton Blanchard <anton@samba.org> Cc: rostedt@goodmis.org Cc: fweisbec@gmail.com LKML-Reference: <20100825013238.GE28360@kryten> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-25workqueue: fix cwq->nr_active underflowTejun Heo
cwq->nr_active is used to keep track of how many work items are active for the cpu workqueue, where 'active' is defined as either pending on global worklist or executing. This is used to implement the max_active limit and workqueue freezing. If a work item is queued after nr_active has already reached max_active, the work item doesn't increment nr_active and is put on the delayed queue and gets activated later as previous active work items retire. try_to_grab_pending() which is used in the cancellation path unconditionally decremented nr_active whether the work item being cancelled is currently active or delayed, so cancelling a delayed work item makes nr_active underflow. This breaks max_active enforcement and triggers BUG_ON() in destroy_workqueue() later on. This patch fixes this bug by adding a flag WORK_STRUCT_DELAYED, which is set while a work item in on the delayed list and making try_to_grab_pending() decrement nr_active iff the work item is currently active. The addition of the flag enlarges cwq alignment to 256 bytes which is getting a bit too large. It's scheduled to be reduced back to 128 bytes by merging WORK_STRUCT_PENDING and WORK_STRUCT_CWQ in the next devel cycle. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Johannes Berg <johannes@sipsolutions.net>
2010-08-24Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: watchdog: Don't throttle the watchdog tracing: Fix timer tracing
2010-08-24Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: mutex: Improve the scalability of optimistic spinning
2010-08-24PM QoS: Fix kzalloc() parameters swapped in pm_qos_power_open()David Alan Gilbert
sparse spotted that the kzalloc() in pm_qos_power_open() in the current Linus' git tree had its parameters swapped. Fix this. Signed-off-by: David Alan Gilbert <linux@treblig.org> Acked-by: mark gross <markgross@thegnar.org> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2010-08-24workqueue: improve destroy_workqueue() debuggabilityTejun Heo
Now that the worklist is global, having works pending after wq destruction can easily lead to oops and destroy_workqueue() have several BUG_ON()s to catch these cases. Unfortunately, BUG_ON() doesn't tell much about how the work became pending after the final flush_workqueue(). This patch adds WQ_DYING which is set before the final flush begins. If a work is requested to be queued on a dying workqueue, WARN_ON_ONCE() is triggered and the request is ignored. This clearly indicates which caller is trying to queue a work on a dying workqueue and keeps the system working in most cases. Locking rule comment is updated such that the 'I' rule includes modifying the field from destruction path. Signed-off-by: Tejun Heo <tj@kernel.org>
2010-08-23workqueue: mark lock acquisition on worker_maybe_bind_and_lock()Namhyung Kim
worker_maybe_bind_and_lock() actually grabs gcwq->lock but was missing proper annotation. Add it. So this patch will remove following sparse warnings: kernel/workqueue.c:1214:13: warning: context imbalance in 'worker_maybe_bind_and_lock' - wrong count at exit arch/x86/include/asm/irqflags.h:44:9: warning: context imbalance in 'worker_rebind_fn' - unexpected unlock kernel/workqueue.c:1991:17: warning: context imbalance in 'rescuer_thread' - unexpected unlock Signed-off-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2010-08-23workqueue: annotate lock context changeNamhyung Kim
Some of internal functions called within gcwq->lock context releases and regrabs the lock but were missing proper annotations. Add it. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2010-08-23mutex: Improve the scalability of optimistic spinningTim Chen
There is a scalability issue for current implementation of optimistic mutex spin in the kernel. It is found on a 8 node 64 core Nehalem-EX system (HT mode). The intention of the optimistic mutex spin is to busy wait and spin on a mutex if the owner of the mutex is running, in the hope that the mutex will be released soon and be acquired, without the thread trying to acquire mutex going to sleep. However, when we have a large number of threads, contending for the mutex, we could have the mutex grabbed by other thread, and then another ……, and we will keep spinning, wasting cpu cycles and adding to the contention. One possible fix is to quit spinning and put the current thread on wait-list if mutex lock switch to a new owner while we spin, indicating heavy contention (see the patch included). I did some testing on a 8 socket Nehalem-EX system with a total of 64 cores. Using Ingo's test-mutex program that creates/delete files with 256 threads (http://lkml.org/lkml/2006/1/8/50) , I see the following speed up after putting in the mutex spin fix: ./mutex-test V 256 10 Ops/sec 2.6.34 62864 With fix 197200 Repeating the test with Aim7 fserver workload, again there is a speed up with the fix: Jobs/min 2.6.34 91657 With fix 149325 To look at the impact on the distribution of mutex acquisition time, I collected the mutex acquisition time on Aim7 fserver workload with some instrumentation. The average acquisition time is reduced by 48% and number of contentions reduced by 32%. #contentions Time to acquire mutex (cycles) 2.6.34 72973 44765791 With fix 49210 23067129 The histogram of mutex acquisition time is listed below. The acquisition time is in 2^bin cycles. We see that without the fix, the acquisition time is mostly around 2^26 cycles. With the fix, we the distribution get spread out a lot more towards the lower cycles, starting from 2^13. However, there is an increase of the tail distribution with the fix at 2^28 and 2^29 cycles. It seems a small price to pay for the reduced average acquisition time and also getting the cpu to do useful work. Mutex acquisition time distribution (acq time = 2^bin cycles): 2.6.34 With Fix bin #occurrence % #occurrence % 11 2 0.00% 120 0.24% 12 10 0.01% 790 1.61% 13 14 0.02% 2058 4.18% 14 86 0.12% 3378 6.86% 15 393 0.54% 4831 9.82% 16 710 0.97% 4893 9.94% 17 815 1.12% 4667 9.48% 18 790 1.08% 5147 10.46% 19 580 0.80% 6250 12.70% 20 429 0.59% 6870 13.96% 21 311 0.43% 1809 3.68% 22 255 0.35% 2305 4.68% 23 317 0.44% 916 1.86% 24 610 0.84% 233 0.47% 25 3128 4.29% 95 0.19% 26 63902 87.69% 122 0.25% 27 619 0.85% 286 0.58% 28 0 0.00% 3536 7.19% 29 0 0.00% 903 1.83% 30 0 0.00% 0 0.00% I've done similar experiments with 2.6.35 kernel on smaller boxes as well. One is on a dual-socket Westmere box (12 cores total, with HT). Another experiment is on an old dual-socket Core 2 box (4 cores total, no HT) On the 12-core Westmere box, I see a 250% increase for Ingo's mutex-test program with my mutex patch but no significant difference in aim7's fserver workload. On the 4-core Core 2 box, I see the difference with the patch for both mutex-test and aim7 fserver are negligible. So far, it seems like the patch has not caused regression on smaller systems. Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: <stable@kernel.org> # .35.x LKML-Reference: <1282168827.9542.72.camel@schen9-DESK> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-23watchdog: Don't throttle the watchdogPeter Zijlstra
Stephane reported that when the machine locks up, the regular ticks, which are responsible to resetting the throttle count, stop too. Hence the NMI watchdog can end up being throttled before it reports on the locked up state, and we end up being sad.. Cure this by having the watchdog overflow reset its own throttle count. Reported-by: Stephane Eranian <eranian@google.com> Tested-by: Stephane Eranian <eranian@google.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1282215916.1926.4696.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-21workqueue: Add basic tracepoints to track workqueue executionArjan van de Ven
With the introduction of the new unified work queue thread pools, we lost one feature: It's no longer possible to know which worker is causing the CPU to wake out of idle. The result is that PowerTOP now reports a lot of "kworker/a:b" instead of more readable results. This patch adds a pair of tracepoints to the new workqueue code, similar in style to the timer/hrtimer tracepoints. With this pair of tracepoints, the next PowerTOP can correctly report which work item caused the wakeup (and how long it took): Interrupt (43) i915 time 3.51ms wakeups 141 Work ieee80211_iface_work time 0.81ms wakeups 29 Work do_dbs_timer time 0.55ms wakeups 24 Process Xorg time 21.36ms wakeups 4 Timer sched_rt_period_timer time 0.01ms wakeups 1 Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-21mm: make the vma list be doubly linkedLinus Torvalds
It's a really simple list, and several of the users want to go backwards in it to find the previous vma. So rather than have to look up the previous entry with 'find_vma_prev()' or something similar, just make it doubly linked instead. Tested-by: Ian Campbell <ijc@hellion.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-21Input: sysrq - drop tty argument form handle_sysrq()Dmitry Torokhov
Sysrq operations do not accept tty argument anymore so no need to pass it to us. [Stephen Rothwell <sfr@canb.auug.org.au>: fix build breakage in drm code caused by sysrq using bool but not including linux/types.h] [Sachin Sant <sachinp@in.ibm.com>: fix build breakage in s390 keyboadr driver] Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Acked-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2010-08-20kfifo: implement missing __kfifo_skip_r()Andrea Righi
kfifo_skip() is currently broken, due to the missing of the internal helper function. Add it. Signed-off-by: Andrea Righi <arighi@develer.com> Cc: Greg KH <greg@kroah.com> Acked-by: Stefani Seibold <stefani@seibold.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-20sched: Fix rq->clock synchronization when migrating tasksPeter Zijlstra
sched_fork() -- we do task placement in ->task_fork_fair() ensure we update_rq_clock() so we work with current time. We leave the vruntime in relative state, so the time delay until wake_up_new_task() doesn't matter. wake_up_new_task() -- Since task_fork_fair() left p->vruntime in relative state we can safely migrate, the activate_task() on the remote rq will call update_rq_clock() and causes the clock to be synced (enough). Tested-by: Jack Daniel <wanders.thirst@gmail.com> Tested-by: Philby John <pjohn@mvista.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1281002322.1923.1708.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-19Input: sysrq - drop tty argument from sysrq ops handlersDmitry Torokhov
Noone is using tty argument so let's get rid of it. Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Acked-by: Jason Wessel <jason.wessel@windriver.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2010-08-18Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: fs: brlock vfsmount_lock fs: scale files_lock lglock: introduce special lglock and brlock spin locks tty: fix fu_list abuse fs: cleanup files_lock locking fs: remove extra lookup in __lookup_hash fs: fs_struct rwlock to spinlock apparmor: use task path helpers fs: dentry allocation consolidation fs: fix do_lookup false negative mbcache: Limit the maximum number of cache entries hostfs ->follow_link() braino hostfs: dumb (and usually harmless) tpyo - strncpy instead of strlcpy remove SWRITE* I/O types kill BH_Ordered flag vfs: update ctime when changing the file's permission by setfacl cramfs: only unlock new inodes fix reiserfs_evict_inode end_writeback second call
2010-08-18Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf tools: Fix build on POSIX shells latencytop: Fix kconfig dependency warnings perf annotate tui: Fix exit and RIGHT keys handling tracing: Sanitize value returned from write(trace_marker, "...", len) tracing/events: Convert format output to seq_file tracing: Extend recordmcount to better support Blackfin mcount tracing: Fix ring_buffer_read_page reading out of page boundary tracing: Fix an unallocated memory access in function_graph
2010-08-18fs: fs_struct rwlock to spinlockNick Piggin
fs: fs_struct rwlock to spinlock struct fs_struct.lock is an rwlock with the read-side used to protect root and pwd members while taking references to them. Taking a reference to a path typically requires just 2 atomic ops, so the critical section is very small. Parallel read-side operations would have cacheline contention on the lock, the dentry, and the vfsmount cachelines, so the rwlock is unlikely to ever give a real parallelism increase. Replace it with a spinlock to avoid one or two atomic operations in typical path lookup fastpath. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-17Merge branch 'for_linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb * 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb: vt,console,kdb: preserve console_blanked while in kdb vt: fix regression warnings from KMS merge arm,kgdb: fix GDB_MAX_REGS no longer used kgdb: add missing __percpu markup in arch/x86/kernel/kgdb.c kdb: fix compile error without CONFIG_KALLSYMS
2010-08-17Fix unprotected access to task credentials in waitid()Daniel J Blueman
Using a program like the following: #include <stdlib.h> #include <unistd.h> #include <sys/types.h> #include <sys/wait.h> int main() { id_t id; siginfo_t infop; pid_t res; id = fork(); if (id == 0) { sleep(1); exit(0); } kill(id, SIGSTOP); alarm(1); waitid(P_PID, id, &infop, WCONTINUED); return 0; } to call waitid() on a stopped process results in access to the child task's credentials without the RCU read lock being held - which may be replaced in the meantime - eliciting the following warning: =================================================== [ INFO: suspicious rcu_dereference_check() usage. ] --------------------------------------------------- kernel/exit.c:1460 invoked rcu_dereference_check() without protection! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 2 locks held by waitid02/22252: #0: (tasklist_lock){.?.?..}, at: [<ffffffff81061ce5>] do_wait+0xc5/0x310 #1: (&(&sighand->siglock)->rlock){-.-...}, at: [<ffffffff810611da>] wait_consider_task+0x19a/0xbe0 stack backtrace: Pid: 22252, comm: waitid02 Not tainted 2.6.35-323cd+ #3 Call Trace: [<ffffffff81095da4>] lockdep_rcu_dereference+0xa4/0xc0 [<ffffffff81061b31>] wait_consider_task+0xaf1/0xbe0 [<ffffffff81061d15>] do_wait+0xf5/0x310 [<ffffffff810620b6>] sys_waitid+0x86/0x1f0 [<ffffffff8105fce0>] ? child_wait_callback+0x0/0x70 [<ffffffff81003282>] system_call_fastpath+0x16/0x1b This is fixed by holding the RCU read lock in wait_task_continued() to ensure that the task's current credentials aren't destroyed between us reading the cred pointer and us reading the UID from those credentials. Furthermore, protect wait_task_stopped() in the same way. We don't need to keep holding the RCU read lock once we've read the UID from the credentials as holding the RCU read lock doesn't stop the target task from changing its creds under us - so the credentials may be outdated immediately after we've read the pointer, lock or no lock. Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-17Make do_execve() take a const filename pointerDavid Howells
Make do_execve() take a const filename pointer so that kernel_execve() compiles correctly on ARM: arch/arm/kernel/sys_arm.c:88: warning: passing argument 1 of 'do_execve' discards qualifiers from pointer target type This also requires the argv and envp arguments to be consted twice, once for the pointer array and once for the strings the array points to. This is because do_execve() passes a pointer to the filename (now const) to copy_strings_kernel(). A simpler alternative would be to cast the filename pointer in do_execve() when it's passed to copy_strings_kernel(). do_execve() may not change any of the strings it is passed as part of the argv or envp lists as they are some of them in .rodata, so marking these strings as const should be fine. Further kernel_execve() and sys_execve() need to be changed to match. This has been test built on x86_64, frv, arm and mips. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-16kdb: fix compile error without CONFIG_KALLSYMSJason Wessel
If CONFIG_KGDB_KDB is set and CONFIG_KALLSYMS is not set the kernel will fail to build with the error: kernel/built-in.o: In function `kallsyms_symbol_next': kernel/debug/kdb/kdb_support.c:237: undefined reference to `kdb_walk_kallsyms' kernel/built-in.o: In function `kallsyms_symbol_complete': kernel/debug/kdb/kdb_support.c:193: undefined reference to `kdb_walk_kallsyms' The kdb_walk_kallsyms needs a #ifdef proper header to match the C implementation. This patch also fixes the compiler warnings in kdb_support.c when compiling without CONFIG_KALLSYMS set. The compiler warnings are a result of the kallsyms_lookup() macro not initializing the two of the pass by reference variables. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Reported-by: Michal Simek <monstr@monstr.eu>
2010-08-16Merge branch 'tip/perf/urgent-3' of ↵Steven Rostedt
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into trace/tip/perf/urgent-4 Conflicts: kernel/trace/trace_events.c Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-08-16workqueue: free rescuer on destroy_workqueueXiaotian Feng
wq->rescuer is not freed when wq is destroyed, leads a memory leak then. This patch also remove a redundant line. Signed-off-by: Xiaotian Feng <dfeng@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com>
2010-08-13tracing: Sanitize value returned from write(trace_marker, "...", len)Marcin Slusarz
When userspace code writes non-new-line-terminated string to trace_marker file, write handler appends new-line and returns number of bytes written to trace buffer, so write(fd, "abc", 3) will return 4 That's unexpected and unfortunately it confuses glibc's fprintf function. Example: int main() { fprintf(stderr, "abc"); return 0; } $ gcc test.c -o test $ echo mmiotrace > /sys/kernel/debug/tracing/current_tracer $ ./test 2>/sys/kernel/debug/tracing/trace_marker results in infinite loop: write(fd, "abc", 3) = 4 write(fd, "", 1) = 0 write(fd, "", 1) = 0 write(fd, "", 1) = 0 write(fd, "", 1) = 0 write(fd, "", 1) = 0 write(fd, "", 1) = 0 write(fd, "", 1) = 0 (...) ...and kernel trace buffer full of empty markers. Fix it by sanitizing write return value. Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com> LKML-Reference: <20100727231801.GB2826@joi.lan> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-08-13time: Workaround gcc loop optimization that causes 64bit div errorsJohn Stultz
Early 4.3 versions of gcc apparently aggressively optimize the raw time accumulation loop, replacing it with a divide. On 32bit systems, this causes the following link errors: undefined reference to `__umoddi3' undefined reference to `__udivdi3' The gcc issue has been fixed in 4.4 and greater. This patch replaces the accumulation loop with a do_div, as suggested by Linus. Signed-off-by: John Stultz <johnstul@us.ibm.com> CC: Jason Wessel <jason.wessel@windriver.com> CC: Larry Finger <Larry.Finger@lwfinger.net> CC: Ingo Molnar <mingo@elte.hu> CC: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12Revert "fsnotify: store struct file not struct path"Linus Torvalds
This reverts commit 3bcf3860a4ff9bbc522820b4b765e65e4deceb3e (and the accompanying commit c1e5c954020e "vfs/fsnotify: fsnotify_close can delay the final work in fput" that was a horribly ugly hack to make it work at all). The 'struct file' approach not only causes that disgusting hack, it somehow breaks pulseaudio, probably due to some other subtlety with f_count handling. Fix up various conflicts due to later fsnotify work. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12tracing/events: Convert format output to seq_fileSteven Rostedt
Two new events were added that broke the current format output. Both from the SCSI system: scsi_dispatch_cmd_done and scsi_dispatch_cmd_timeout The reason is that their print_fmt exceeded a page size. Since the output of the format used simple_read_from_buffer and trace_seq, it was limited to a page size in output. This patch converts the printing of the format of an event into seq_file, which allows greater than a page size to be shown. I diffed all event formats comparing the output with and without this patch. All matched except for the above two, which showed just: FORMAT TOO BIG without this patch, but now properly displays the output with this patch. v2: Remove updating *pos in seq start function. [ Thanks to Li Zefan for pointing that out ] Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Kei Tokunaga <tokunaga.keiich@jp.fujitsu.com> Cc: James Bottomley <James.Bottomley@suse.de> Cc: Tomohiro Kusumi <kusumi.tomohiro@jp.fujitsu.com> Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-08-12Merge branch 'params' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus * 'params' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (22 commits) param: don't deref arg in __same_type() checks param: update drivers/acpi/debug.c to new scheme param: use module_param in drivers/message/fusion/mptbase.c ide: use module_param_named rather than module_param_call param: update drivers/char/ipmi/ipmi_watchdog.c to new scheme param: lock if_sdio's lbs_helper_name and lbs_fw_name against sysfs changes. param: lock myri10ge_fw_name against sysfs changes. param: simple locking for sysfs-writable charp parameters param: remove unnecessary writable charp param: add kerneldoc to moduleparam.h param: locking for kernel parameters param: make param sections const. param: use free hook for charp (fix leak of charp parameters) param: add a free hook to kernel_param_ops. param: silence .init.text references from param ops Add param ops struct for hvc_iucv driver. nfs: update for module_param_named API change AppArmor: update for module_param_named API change param: use ops in struct kernel_param, rather than get and set fns directly param: move the EXPORT_SYMBOL to after the definitions. ...
2010-08-12timekeeping: Fix overflow in rawtime tv_nsec on 32 bit archsJason Wessel
The tv_nsec is a long and when added to the shifted interval it can wrap and become negative which later causes looping problems in the getrawmonotonic(). The edge case occurs when the system has slept for a short period of time of ~2 seconds. A trace printk of the values in this patch illustrate the problem: ftrace time stamp: log 43.716079: logarithmic_accumulation: raw: 3d0913 tv_nsec d687faa 43.718513: logarithmic_accumulation: raw: 3d0913 tv_nsec da588bd 43.722161: logarithmic_accumulation: raw: 3d0913 tv_nsec de291d0 46.349925: logarithmic_accumulation: raw: 7a122600 tv_nsec e1f9ae3 46.349930: logarithmic_accumulation: raw: 1e848980 tv_nsec 8831c0e3 The kernel starts looping at 46.349925 in the getrawmonotonic() due to the negative value from adding the raw value to tv_nsec. A simple solution is to accumulate into a u64, and then normalize it to a timespec_t. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> [ Reworked variable names and simplified some of the code. - John ] Signed-off-by: John Stultz <johnstul@us.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12Add a dummy printk function for the maintenance of unused printksDavid Howells
Add a dummy printk function for the maintenance of unused printks through gcc format checking, and also so that side-effect checking is maintained too. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12block: add secure discardAdrian Hunter
Secure discard is the same as discard except that all copies of the discarded sectors (perhaps created by garbage collection) must also be erased. Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com> Acked-by: Jens Axboe <axboe@kernel.dk> Cc: Kyungmin Park <kmpark@infradead.org> Cc: Madhusudhan Chikkature <madhu.cr@ti.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ben Gardiner <bengardiner@nanometrics.ca> Cc: <linux-mmc@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-12kernel/kfifo.c: add handling of chained scatterlistsStefani Seibold
The current kfifo scatterlist implementation will not work with chained scatterlists. It assumes that struct scatterlist arrays are allocated contiguously, which is not the case when chained scatterlists (struct sg_table) are in use. Signed-off-by: Stefani Seibold <stefani@seibold.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: isofs: Fix lseek() to position beyond 4 GB vfs: remove unused MNT_STRICTATIME vfs: show unreachable paths in getcwd and proc vfs: only add " (deleted)" where necessary vfs: add prepend_path() helper vfs: __d_path: dont prepend the name of the root dentry ia64: perfmon: add d_dname method vfs: add helpers to get root and pwd cachefiles: use path_get instead of lone dget fs/sysv/super.c: add support for non-PDP11 v7 filesystems V7: Adjust sanity checks for some volumes Add v7 alias v9fs: fixup for inode_setattr being removed Manual merge to take Al's version of the fs/sysv/super.c file: it merged cleanly, but Al had removed an unnecessary header include, so his side was better.
2010-08-11kfifo: replace the old non generic APIStefani Seibold
Simply replace the whole kfifo.c and kfifo.h files with the new generic version and fix the kerneldoc API template file. Signed-off-by: Stefani Seibold <stefani@seibold.net> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11kfifo: add the new generic kfifo APIStefani Seibold
Add the new version of the kfifo API files kfifo.c and kfifo.h. Signed-off-by: Stefani Seibold <stefani@seibold.net> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11kexec: return -EFAULT on copy_to_user() failuresDan Carpenter
copy_to/from_user() returns the number of bytes remaining to be copied. It never returns a negative value. The correct return code is -EFAULT and not -EIO. All the callers check for non-zero returns so that's Ok, but the return code is passed to the user so we should fix this. Signed-off-by: Dan Carpenter <error27@gmail.com> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Simon Kagstrom <simon.kagstrom@netinsight.net> Acked-by: WANG Cong <xiyou.wangcong@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11lib/bug.c: add oops end marker to WARN implementationAnton Blanchard
We are missing the oops end marker for the exception based WARN implementation in lib/bug.c. This is useful for logfile analysis tools. Signed-off-by: Anton Blanchard <anton@samba.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Arjan van de Ven <arjan@infradead.org> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11panic: keep blinking in spite of long spin timer modeTAMUKI Shoichi
To keep panic_timeout accuracy when running under a hypervisor, the current implementation only spins on long time (1 second) calls to mdelay. That brings a good effect, but the problem is the keyboard LEDs don't blink at all on that situation. This patch changes to call to panic_blink_enter() between every mdelay and keeps blinking in spite of long spin timer mode. The time to call to mdelay is now 100ms. Even this change will keep panic_timeout accuracy enough when running under a hypervisor. Signed-off-by: TAMUKI Shoichi <tamuki@linet.gr.jp> Cc: Ben Dooks <ben-linux@fluff.org> Cc: Russell King <linux@arm.linux.org.uk> Acked-by: Dmitry Torokhov <dtor@mail.ru> Cc: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11pids: alloc_pidmap: remove the unnecessary boundary checksOleg Nesterov
alloc_pidmap() calculates max_scan so that if the initial offset != 0 we inspect the first map->page twice. This is correct, we want to find the unused bits < offset in this bitmap block. Add the comment. But it doesn't make any sense to stop the find_next_offset() loop when we are looking into this map->page for the second time. We have already already checked the bits >= offset during the first attempt, it is fine to do this again, no matter if we succeed this time or not. Remove this hard-to-understand code. It optimizes the very unlikely case when we are going to fail, but slows down the more likely case. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Salman Qazi <sqazi@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11pids: fix a race in pid generation that causes pids to be reused immediatelySalman
A program that repeatedly forks and waits is susceptible to having the same pid repeated, especially when it competes with another instance of the same program. This is really bad for bash implementation. Furthermore, many shell scripts assume that pid numbers will not be used for some length of time. Race Description: A B // pid == offset == n // pid == offset == n + 1 test_and_set_bit(offset, map->page) test_and_set_bit(offset, map->page); pid_ns->last_pid = pid; pid_ns->last_pid = pid; // pid == n + 1 is freed (wait()) // Next fork()... last = pid_ns->last_pid; // == n pid = last + 1; Code to reproduce it (Running multiple instances is more effective): #include <errno.h> #include <sys/types.h> #include <sys/wait.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> // The distance mod 32768 between two pids, where the first pid is expected // to be smaller than the second. int PidDistance(pid_t first, pid_t second) { return (second + 32768 - first) % 32768; } int main(int argc, char* argv[]) { int failed = 0; pid_t last_pid = 0; int i; printf("%d\n", sizeof(pid_t)); for (i = 0; i < 10000000; ++i) { if (i % 32786 == 0) printf("Iter: %d\n", i/32768); int child_exit_code = i % 256; pid_t pid = fork(); if (pid == -1) { fprintf(stderr, "fork failed, iteration %d, errno=%d", i, errno); exit(1); } if (pid == 0) { // Child exit(child_exit_code); } else { // Parent if (i > 0) { int distance = PidDistance(last_pid, pid); if (distance == 0 || distance > 30000) { fprintf(stderr, "Unexpected pid sequence: previous fork: pid=%d, " "current fork: pid=%d for iteration=%d.\n", last_pid, pid, i); failed = 1; } } last_pid = pid; int status; int reaped = wait(&status); if (reaped != pid) { fprintf(stderr, "Wait return value: expected pid=%d, " "got %d, iteration %d\n", pid, reaped, i); failed = 1; } else if (WEXITSTATUS(status) != child_exit_code) { fprintf(stderr, "Unexpected exit status %x, iteration %d\n", WEXITSTATUS(status), i); failed = 1; } } } exit(failed); } Thanks to Ted Tso for the key ideas of this implementation. Signed-off-by: Salman Qazi <sqazi@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11ptrace: optimize exit_ptrace() for the likely caseOleg Nesterov
exit_ptrace() takes tasklist_lock unconditionally. We need this lock to avoid the race with ptrace_traceme(), it acts as a barrier. Change its caller, forget_original_parent(), to call exit_ptrace() under tasklist_lock. Change exit_ptrace() to drop and reacquire this lock if needed. This allows us to add the fastpath list_empty(ptraced) check. In the likely no-tracees case exit_ptrace() just returns and we avoid the lock() + unlock() sequence. "Zhang, Yanmin" <yanmin_zhang@linux.intel.com> suggested to add this check, and he reports that this change adds about 11% improvement in some tests. Suggested-and-tested-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11cgroups: save space for the terminatorDan Carpenter
The original code didn't leave enough space for a NULL terminator. These strings are copied with strcpy() into fixed length buffers in cgroup_root_from_opts(). Signed-off-by: Dan Carpenter <error27@gmail.com> Acked-by: Serge E. Hallyn <serge@hallyn.com> Reviewd-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Ben Blum <bblum@andrew.cmu.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-08-11param: locking for kernel parametersRusty Russell
There may be cases (most obviously, sysfs-writable charp parameters) where a module needs to prevent sysfs access to parameters. Rather than express this in terms of a big lock, the functions are expressed in terms of what they protect against. This is clearer, esp. if the implementation changes to a module-level or even param-level lock. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Reviewed-by: Takashi Iwai <tiwai@suse.de> Tested-by: Phil Carmody <ext-phil.2.carmody@nokia.com>
2010-08-11param: make param sections const.Rusty Russell
Since this section can be read-only (they're in .rodata), they should always have been const. Minor flow-through various functions. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Tested-by: Phil Carmody <ext-phil.2.carmody@nokia.com>