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Groups > linux.kernel > #1251199
| From | lizf@kernel.org |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 3.4 44/65] mm: kmemleak: allow safe memory scanning during kmemleak disabling |
| Date | 2015-10-20 03:00 +0200 |
| Message-ID | <qltrs-4x1-19@gated-at.bofh.it> (permalink) |
| References | <qlthL-4kA-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
From: Catalin Marinas <catalin.marinas@arm.com>
3.4.110-rc1 review patch. If anyone has any objections, please let me know.
------------------
commit c5f3b1a51a591c18c8b33983908e7fdda6ae417e upstream.
The kmemleak scanning thread can run for minutes. Callbacks like
kmemleak_free() are allowed during this time, the race being taken care
of by the object->lock spinlock. Such lock also prevents a memory block
from being freed or unmapped while it is being scanned by blocking the
kmemleak_free() -> ... -> __delete_object() function until the lock is
released in scan_object().
When a kmemleak error occurs (e.g. it fails to allocate its metadata),
kmemleak_enabled is set and __delete_object() is no longer called on
freed objects. If kmemleak_scan is running at the same time,
kmemleak_free() no longer waits for the object scanning to complete,
allowing the corresponding memory block to be freed or unmapped (in the
case of vfree()). This leads to kmemleak_scan potentially triggering a
page fault.
This patch separates the kmemleak_free() enabling/disabling from the
overall kmemleak_enabled nob so that we can defer the disabling of the
object freeing tracking until the scanning thread completed. The
kmemleak_free_part() is deliberately ignored by this patch since this is
only called during boot before the scanning thread started.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Vignesh Radhakrishnan <vigneshr@codeaurora.org>
Tested-by: Vignesh Radhakrishnan <vigneshr@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
mm/kmemleak.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index ad6ee88..c74827c 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -193,6 +193,8 @@ static struct kmem_cache *scan_area_cache;
/* set if tracing memory operations is enabled */
static atomic_t kmemleak_enabled = ATOMIC_INIT(0);
+/* same as above but only for the kmemleak_free() callback */
+static int kmemleak_free_enabled;
/* set in the late_initcall if there were no errors */
static atomic_t kmemleak_initialized = ATOMIC_INIT(0);
/* enables or disables early logging of the memory operations */
@@ -936,7 +938,7 @@ void __ref kmemleak_free(const void *ptr)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
- if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
+ if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
delete_object_full((unsigned long)ptr);
else if (atomic_read(&kmemleak_early_log))
log_early(KMEMLEAK_FREE, ptr, 0, 0);
@@ -976,7 +978,7 @@ void __ref kmemleak_free_percpu(const void __percpu *ptr)
pr_debug("%s(0x%p)\n", __func__, ptr);
- if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
+ if (kmemleak_free_enabled && ptr && !IS_ERR(ptr))
for_each_possible_cpu(cpu)
delete_object_full((unsigned long)per_cpu_ptr(ptr,
cpu));
@@ -1690,6 +1692,13 @@ static void kmemleak_do_cleanup(struct work_struct *work)
mutex_lock(&scan_mutex);
stop_scan_thread();
+ /*
+ * Once the scan thread has stopped, it is safe to no longer track
+ * object freeing. Ordering of the scan thread stopping and the memory
+ * accesses below is guaranteed by the kthread_stop() function.
+ */
+ kmemleak_free_enabled = 0;
+
if (cleanup) {
rcu_read_lock();
list_for_each_entry_rcu(object, &object_list, object_list)
@@ -1717,6 +1726,8 @@ static void kmemleak_disable(void)
/* check whether it is too early for a kernel thread */
if (atomic_read(&kmemleak_initialized))
schedule_work(&cleanup_work);
+ else
+ kmemleak_free_enabled = 0;
pr_info("Kernel memory leak detector disabled\n");
}
@@ -1782,8 +1793,10 @@ void __init kmemleak_init(void)
if (atomic_read(&kmemleak_error)) {
local_irq_restore(flags);
return;
- } else
+ } else {
atomic_set(&kmemleak_enabled, 1);
+ kmemleak_free_enabled = 1;
+ }
local_irq_restore(flags);
/*
--
1.9.1
--
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[PATCH 3.4 00/65] 3.4.110-rc1 review lizf@kernel.org - 2015-10-20 02:50 +0200
[PATCH 3.4 16/65] usb: core: Fix USB 3.0 devices lost in NOTATTACHED state after a hub port reset lizf@kernel.org - 2015-10-20 02:50 +0200
[PATCH 3.4 50/65] crush: fix a bug in tree bucket decode lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 54/65] KVM: x86: properly restore LVT0 lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 56/65] Revert "drm/i915: Don't skip request retirement if the active list is empty" lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 43/65] stmmac: troubleshoot unexpected bits in des0 & des1 lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 35/65] nfs: increase size of EXCHANGE_ID name string buffer lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 55/65] 9p: forgetting to cancel request on interrupted zero-copy RPC lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 46/65] tracing/filter: Do not WARN on operand count going below zero lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 61/65] usb: dwc3: Reset the transfer resource index on SET_INTERFACE lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 24/65] x86/PCI: Use host bridge _CRS info on Foxconn K8M890-8237A lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 44/65] mm: kmemleak: allow safe memory scanning during kmemleak disabling lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 23/65] regulator: core: fix constraints output buffer lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 60/65] ARM: Fix incorrect backport of 0b59d8806a31 lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 40/65] ext4: don't retry file block mapping on bigalloc fs with non-extent file lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 30/65] jbd2: use GFP_NOFS in jbd2_cleanup_journal_tail() lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 63/65] IB/qib: Change lkey table allocation to support more MRs lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 65/65] vfs: Test for and handle paths that are unreachable from their mnt_root lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 62/65] jbd2: avoid infinite loop when destroying aborted journal lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 37/65] ext4: call sync_blockdev() before invalidate_bdev() in put_super() lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 48/65] __bitmap_parselist: fix bug in empty string handling lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 59/65] crypto: s390/ghash: Fix incorrect backport of a1cae34e23b1 lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 47/65] tracing/filter: Do not allow infix to exceed end of string lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 58/65] drm/radeon: partially revert "fix VM_CONTEXT*_PAGE_TABLE_END_ADDR handling" lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 52/65] ACPICA: Tables: Fix an issue that FACS initialization is performed twice lizf@kernel.org - 2015-10-20 03:00 +0200
RE: [PATCH 3.4 52/65] ACPICA: Tables: Fix an issue that FACS initialization is performed twice "Moore, Robert" <robert.moore@intel.com> - 2015-10-20 15:40 +0200
RE: [PATCH 3.4 52/65] ACPICA: Tables: Fix an issue that FACS initialization is performed twice "Zheng, Lv" <lv.zheng@intel.com> - 2015-10-21 03:30 +0200
[PATCH 3.4 53/65] KVM: x86: make vapics_in_nmi_mode atomic lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 34/65] mmc: card: Fixup request missing in mmc_blk_issue_rw_rq lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 42/65] bridge: multicast: restore router configuration on port link down/up lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 64/65] dcache: Handle escaped paths in prepend_path lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 36/65] bridge: fix br_stp_set_bridge_priority race conditions lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 51/65] fuse: initialize fc->release before calling it lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 38/65] packet: read num_members once in packet_rcv_fanout() lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 57/65] Revert "drm/radeon: Use drm_calloc_ab for CS relocs" lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 49/65] agp/intel: Fix typo in needs_ilk_vtd_wa() lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 27/65] ext4: fix race between truncate and __ext4_journalled_writepage() lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 39/65] packet: avoid out of bounds read in round robin fanout lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 45/65] dell-laptop: Fix allocating & freeing SMI buffer page lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 41/65] watchdog: omap: assert the counter being stopped before reprogramming lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 25/65] dmaengine: mv_xor: bug fix for racing condition in descriptors cleanup lizf@kernel.org - 2015-10-20 03:00 +0200
[PATCH 3.4 33/65] ideapad: fix software rfkill setting lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 19/65] SUNRPC: Fix a memory leak in the backchannel code lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 10/65] rndis_wlan: harmless issue calling set_bit() lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 32/65] jbd2: fix ocfs2 corrupt when updating journal superblock fails lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 12/65] usb: dwc3: gadget: return error if command sent to DEPCMD register fails lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 20/65] ipr: Increase default adapter init stage change timeout lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 26/65] ASoC: wm8960: the enum of "DAC Polarity" should be wm8960_enum[1] lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 06/65] ASoC: wm8955: Fix setting wrong register for WM8955_K_8_0_MASK bits lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 01/65] hrtimer: Allow concurrent hrtimer_start() for self restarting timers lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 09/65] tty/serial: at91: RS485 mode: 0 is valid for delay_rts_after_send lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 28/65] Disable write buffering on Toshiba ToPIC95 lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 13/65] rcu: Correctly handle non-empty Tiny RCU callback list with none ready lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 22/65] ath9k: fix DMA stop sequence for AR9003+ lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 31/65] regmap: Fix regmap_bulk_read in BE mode lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 15/65] staging: rtl8712: prevent buffer overrun in recvbuf2recvframe lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 02/65] mtd: fix: avoid race condition when accessing mtd->usecount lizf@kernel.org - 2015-10-20 03:10 +0200
[PATCH 3.4 29/65] sctp: fix ASCONF list handling lizf@kernel.org - 2015-10-20 03:10 +0200
Re: [PATCH 3.4 00/65] 3.4.110-rc1 review Guenter Roeck <linux@roeck-us.net> - 2015-10-20 04:20 +0200
Re: [PATCH 3.4 00/65] 3.4.110-rc1 review Geert Uytterhoeven <geert@linux-m68k.org> - 2015-10-20 09:10 +0200
Re: [PATCH 3.4 00/65] 3.4.110-rc1 review Geert Uytterhoeven <geert@linux-m68k.org> - 2015-10-20 11:10 +0200
Re: [PATCH 3.4 00/65] 3.4.110-rc1 review Guenter Roeck <linux@roeck-us.net> - 2015-10-20 15:00 +0200
Re: [PATCH 3.4 00/65] 3.4.110-rc1 review Guenter Roeck <linux@roeck-us.net> - 2015-10-20 15:20 +0200
Re: [PATCH 3.4 00/65] 3.4.110-rc1 review Zefan Li <lizefan@huawei.com> - 2015-10-21 10:10 +0200
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