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* kmemleak: Improve the "Early log buffer exceeded" error messageCatalin Marinas2009-09-111-1/+2
| | | | | | | | Based on a suggestion from Jaswinder, clarify what the user would need to do to avoid this error message from kmemleak. Reported-by: Jaswinder Singh Rajput <jaswinder@kernel.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: fix sparse warning for static declarationsLuis R. Rodriguez2009-09-081-2/+2
| | | | | | | | | | | This fixes these sparse warnings: mm/kmemleak.c:1179:6: warning: symbol 'start_scan_thread' was not declared. Should it be static? mm/kmemleak.c:1194:6: warning: symbol 'stop_scan_thread' was not declared. Should it be static? Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: fix sparse warning over overshadowed flagsLuis R. Rodriguez2009-09-081-4/+3
| | | | | | | | | | | | | A secondary irq_save is not required as a locking before it was already disabling irqs. This fixes this sparse warning: mm/kmemleak.c:512:31: warning: symbol 'flags' shadows an earlier one mm/kmemleak.c:448:23: originally declared here Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: move common painting code togetherLuis R. Rodriguez2009-09-081-28/+41
| | | | | | | | | | When painting grey or black we do the same thing, bring this together into a helper and identify coloring grey or black explicitly with defines. This makes this a little easier to read. Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: add clear command supportLuis R. Rodriguez2009-09-081-0/+26
| | | | | | | | | | | | | | | | | | | | | | | | In an ideal world your kmemleak output will be small, when its not (usually during initial bootup) you can use the clear command to ingore previously reported and unreferenced kmemleak objects. We do this by painting all currently reported unreferenced objects grey. We paint them grey instead of black to allow future scans on the same objects as such objects could still potentially reference newly allocated objects in the future. To test a critical section on demand with a clean /sys/kernel/debug/kmemleak you can do: echo clear > /sys/kernel/debug/kmemleak test your kernel or modules echo scan > /sys/kernel/debug/kmemleak Then as usual to get your report with: cat /sys/kernel/debug/kmemleak Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: use bool for true/false questionsLuis R. Rodriguez2009-09-081-4/+4
| | | | | | Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Do no create the clean-up thread during kmemleak_disable()Catalin Marinas2009-09-081-17/+5
| | | | | | | | | | | The kmemleak_disable() function could be called from various contexts including IRQ. It creates a clean-up thread but the kthread_create() function has restrictions on which contexts it can be called from, mainly because of the kthread_create_lock. The patch changes the kmemleak clean-up thread to a workqueue. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Eric Paris <eparis@redhat.com>
* kmemleak: Scan all thread stacksCatalin Marinas2009-09-041-7/+7
| | | | | | | This patch changes the for_each_process() loop with the do_each_thread()/while_each_thread() pair. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Don't scan uninitialized memory when kmemcheck is enabledPekka Enberg2009-09-041-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ingo Molnar reported the following kmemcheck warning when running both kmemleak and kmemcheck enabled: PM: Adding info for No Bus:vcsa7 WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (f6f6e1a4) d873f9f600000000c42ae4c1005c87f70000000070665f666978656400000000 i i i i u u u u i i i i i i i i i i i i i i i i i i i i i u u u ^ Pid: 3091, comm: kmemleak Not tainted (2.6.31-rc7-tip #1303) P4DC6 EIP: 0060:[<c110301f>] EFLAGS: 00010006 CPU: 0 EIP is at scan_block+0x3f/0xe0 EAX: f40bd700 EBX: f40bd780 ECX: f16b46c0 EDX: 00000001 ESI: f6f6e1a4 EDI: 00000000 EBP: f10f3f4c ESP: c2605fcc DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 CR0: 8005003b CR2: e89a4844 CR3: 30ff1000 CR4: 000006f0 DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 DR6: ffff4ff0 DR7: 00000400 [<c110313c>] scan_object+0x7c/0xf0 [<c1103389>] kmemleak_scan+0x1d9/0x400 [<c1103a3c>] kmemleak_scan_thread+0x4c/0xb0 [<c10819d4>] kthread+0x74/0x80 [<c10257db>] kernel_thread_helper+0x7/0x3c [<ffffffff>] 0xffffffff kmemleak: 515 new suspected memory leaks (see /sys/kernel/debug/kmemleak) kmemleak: 42 new suspected memory leaks (see /sys/kernel/debug/kmemleak) The problem here is that kmemleak will scan partially initialized objects that makes kmemcheck complain. Fix that up by skipping uninitialized memory regions when kmemcheck is enabled. Reported-by: Ingo Molnar <mingo@elte.hu> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
* kmemleak: Printing of the objects hex dumpSergey Senozhatsky2009-08-271-0/+39
| | | | | | | | | | | | Introducing printing of the objects hex dump to the seq file. The number of lines to be printed is limited to HEX_MAX_LINES to prevent seq file spamming. The actual number of printed bytes is less than or equal to (HEX_MAX_LINES * HEX_ROW_SIZE). (slight adjustments by Catalin Marinas) Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@mail.by> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Save the stack trace for early allocationsCatalin Marinas2009-08-271-12/+52
| | | | | | | | | | Before slab is initialised, kmemleak save the allocations in an early log buffer. They are later recorded as normal memory allocations. This patch adds the stack trace saving to the early log buffer, otherwise the information shown for such objects only refers to the kmemleak_init() function. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Mark the early log buffer as __initdataCatalin Marinas2009-08-271-12/+14
| | | | | | | | This buffer isn't needed after kmemleak was initialised so it can be freed together with the .init.data section. This patch also marks functions conditionally accessing the early log variables with __ref. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Dump object information on requestCatalin Marinas2009-08-271-0/+25
| | | | | | | | By writing dump=<addr> to the kmemleak file, kmemleak will look up an object with that address and dump the information it has about it to syslog. This is useful in debugging memory leaks. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Allow rescheduling during an object scanningCatalin Marinas2009-08-271-4/+17
| | | | | | | | | If the object size is bigger than a predefined value (4K in this case), release the object lock during scanning and call cond_resched(). Re-acquire the lock after rescheduling and test whether the object is still valid. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Protect the seq start/next/stop sequence by rcu_read_lock()Catalin Marinas2009-07-291-3/+1
| | | | | | | | | | Objects passed to kmemleak_seq_next() have an incremented reference count (hence not freed) but they may point via object_list.next to other freed objects. To avoid this, the whole start/next/stop sequence must be protected by rcu_read_lock(). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kmemleak: Allow partial freeing of memory blocksCatalin Marinas2009-07-081-14/+81
| | | | | | | | | | | Functions like free_bootmem() are allowed to free only part of a memory block. This patch adds support for this via the kmemleak_free_part() callback which removes the original object and creates one or two additional objects as a result of the memory block split. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
* kmemleak: Scan objects allocated during a scanning episodeCatalin Marinas2009-07-081-3/+40
| | | | | | | | | | | | | | | Many of the false positives in kmemleak happen on busy systems where objects are allocated during a kmemleak scanning episode. These objects aren't scanned by default until the next memory scan. When such object is added, for example, at the head of a list, it is possible that all the other objects in the list become unreferenced until the next scan. This patch adds checking for newly allocated objects at the end of the scan and repeats the scanning on these objects. If Linux allocates new objects at a higher rate than their scanning, it stops after a predefined number of passes. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Do not acquire scan_mutex in kmemleak_open()Catalin Marinas2009-07-081-33/+30
| | | | | | | | | | | Initially, the scan_mutex was acquired in kmemleak_open() and released in kmemleak_release() (corresponding to /sys/kernel/debug/kmemleak operations). This was causing some lockdep reports when the file was closed from a different task than the one opening it. This patch moves the scan_mutex acquiring in kmemleak_write() or kmemleak_seq_start() with releasing in kmemleak_seq_stop(). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Remove the reported leaks number limitationCatalin Marinas2009-07-081-15/+2
| | | | | | | | Since the leaks are no longer printed to the syslog, there is no point in keeping this limitation. All the suspected leaks are shown on /sys/kernel/debug/kmemleak file. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Add more cond_resched() calls in the scanning threadCatalin Marinas2009-07-071-8/+11
| | | | | | | | | | Following recent fix to no longer reschedule in the scan_block() function, the system may become unresponsive with !PREEMPT. This patch re-adds the cond_resched() call to scan_block() but conditioned by the allow_resched parameter. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Ingo Molnar <mingo@elte.hu>
* kmemleak: Renice the scanning thread to +10Catalin Marinas2009-07-071-0/+1
| | | | | | | This is a long-running thread but not high-priority. So it makes sense to renice it to +10. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Fix scheduling-while-atomic bugIngo Molnar2009-07-011-30/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | One of the kmemleak changes caused the following scheduling-while-holding-the-tasklist-lock regression on x86: BUG: sleeping function called from invalid context at mm/kmemleak.c:795 in_atomic(): 1, irqs_disabled(): 0, pid: 1737, name: kmemleak 2 locks held by kmemleak/1737: #0: (scan_mutex){......}, at: [<c10c4376>] kmemleak_scan_thread+0x45/0x86 #1: (tasklist_lock){......}, at: [<c10c3bb4>] kmemleak_scan+0x1a9/0x39c Pid: 1737, comm: kmemleak Not tainted 2.6.31-rc1-tip #59266 Call Trace: [<c105ac0f>] ? __debug_show_held_locks+0x1e/0x20 [<c102e490>] __might_sleep+0x10a/0x111 [<c10c38d5>] scan_yield+0x17/0x3b [<c10c3970>] scan_block+0x39/0xd4 [<c10c3bc6>] kmemleak_scan+0x1bb/0x39c [<c10c4331>] ? kmemleak_scan_thread+0x0/0x86 [<c10c437b>] kmemleak_scan_thread+0x4a/0x86 [<c104d73e>] kthread+0x6e/0x73 [<c104d6d0>] ? kthread+0x0/0x73 [<c100959f>] kernel_thread_helper+0x7/0x10 kmemleak: 834 new suspected memory leaks (see /sys/kernel/debug/kmemleak) The bit causing it is highly dubious: static void scan_yield(void) { might_sleep(); if (time_is_before_eq_jiffies(next_scan_yield)) { schedule(); next_scan_yield = jiffies + jiffies_scan_yield; } } It called deep inside the codepath and in a conditional way, and that is what crapped up when one of the new scan_block() uses grew a tasklist_lock dependency. This minimal patch removes that yielding stuff and adds the proper cond_resched(). The background scanning thread could probably also be reniced to +10. Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kmemleak: Do not warn if an unknown object is freedCatalin Marinas2009-06-291-0/+2
| | | | | | | | | vmap'ed memory blocks are not tracked by kmemleak (yet) but they may be released with vfree() which is tracked. The corresponding kmemleak warning is only enabled in debug mode. Future patch will add support for ioremap and vmap. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Do not report new leaked objects if the scanning was stoppedCatalin Marinas2009-06-291-5/+10
| | | | | | | | If the scanning was stopped with a signal, it is possible that some objects are left with a white colour (potential leaks) and reported. Add a check to avoid reporting such objects. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Slightly change the policy on newly allocated objectsCatalin Marinas2009-06-261-1/+6
| | | | | | | | | | | Newly allocated objects are more likely to be reported as false positives. Kmemleak ignores the reporting of objects younger than 5 seconds. However, this age was calculated after the memory scanning completed which usually takes longer than 5 seconds. This patch make the minimum object age calculation in relation to the start of the memory scanning. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Do not trigger a scan when reading the debug/kmemleak fileCatalin Marinas2009-06-261-50/+40
| | | | | | | | | | Since there is a kernel thread for automatically scanning the memory, it makes sense for the debug/kmemleak file to only show its findings. This patch also adds support for "echo scan > debug/kmemleak" to trigger an intermediate memory scan and eliminates the kmemleak_mutex (scan_mutex covers all the cases now). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Simplify the reports logged by the scanning threadCatalin Marinas2009-06-261-45/+16
| | | | | | | | | Because of false positives, the memory scanning thread may print too much information. This patch changes the scanning thread to only print the number of newly suspected leaks. Further information can be read from the /sys/kernel/debug/kmemleak file. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Enable task stacks scanning by defaultCatalin Marinas2009-06-261-1/+1
| | | | | | This is to reduce the number of false positives reported. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Allow the early log buffer to be configurable.Catalin Marinas2009-06-251-2/+3
| | | | | | | | | | | | | (feature suggested by Sergey Senozhatsky) Kmemleak needs to track all the memory allocations but some of these happen before kmemleak is initialised. These are stored in an internal buffer which may be exceeded in some kernel configurations. This patch adds a configuration option with a default value of 400 and also removes the stack dump when the early log buffer is exceeded. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@mail.by>
* kmemleak: use pr_fmtJoe Perches2009-06-231-28/+24
| | | | | Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Fix some typos in commentsCatalin Marinas2009-06-171-4/+4
| | | | Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
* kmemleak: Rename kmemleak_panic to kmemleak_stopCatalin Marinas2009-06-171-6/+6
| | | | | | | This is to avoid the confusion created by the "panic" word. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
* kmemleak: Only use GFP_KERNEL|GFP_ATOMIC for the internal allocationsCatalin Marinas2009-06-171-2/+5
| | | | | | | | | | | Kmemleak allocates memory for pointer tracking and it tries to avoid using GFP_ATOMIC if the caller doesn't require it. However other gfp flags may be passed by the caller which aren't required by kmemleak. This patch filters the gfp flags so that only GFP_KERNEL | GFP_ATOMIC are used. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
* kmemleak: Add the base supportCatalin Marinas2009-06-111-0/+1498
This patch adds the base support for the kernel memory leak detector. It traces the memory allocation/freeing in a way similar to the Boehm's conservative garbage collector, the difference being that the unreferenced objects are not freed but only shown in /sys/kernel/debug/kmemleak. Enabling this feature introduces an overhead to memory allocations. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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