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2012-03-15memcg: free mem_cgroup by RCU to fix oopsHugh Dickins
After fixing the GPF in mem_cgroup_lru_del_list(), three times one machine running a similar load (moving and removing memcgs while swapping) has oopsed in mem_cgroup_zone_nr_lru_pages(), when retrieving memcg zone numbers for get_scan_count() for shrink_mem_cgroup_zone(): this is where a struct mem_cgroup is first accessed after being chosen by mem_cgroup_iter(). Just what protects a struct mem_cgroup from being freed, in between mem_cgroup_iter()'s css_get_next() and its css_tryget()? css_tryget() fails once css->refcnt is zero with CSS_REMOVED set in flags, yes: but what if that memory is freed and reused for something else, which sets "refcnt" non-zero? Hmm, and scope for an indefinite freeze if refcnt is left at zero but flags are cleared. It's tempting to move the css_tryget() into css_get_next(), to make it really "get" the css, but I don't think that actually solves anything: the same difficulty in moving from css_id found to stable css remains. But we already have rcu_read_lock() around the two, so it's easily fixed if __mem_cgroup_free() just uses kfree_rcu() to free mem_cgroup. However, a big struct mem_cgroup is allocated with vzalloc() instead of kzalloc(), and we're not allowed to vfree() at interrupt time: there doesn't appear to be a general vfree_rcu() to help with this, so roll our own using schedule_work(). The compiler decently removes vfree_work() and vfree_rcu() when the config doesn't need them. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Tejun Heo <tj@kernel.org> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-09memcg: revert fix to mapcount check for this releaseHugh Dickins
Respectfully revert commit e6ca7b89dc76 "memcg: fix mapcount check in move charge code for anonymous page" for the 3.3 release, so that it behaves exactly like releases 2.6.35 through 3.2 in this respect. Horiguchi-san's commit is correct in itself, 1 makes much more sense than 2 in that check; but it does not go far enough - swapcount should be considered too - if we really want such a check at all. We appear to have reached agreement now, and expect that 3.4 will remove the mapcount check, but had better not make 3.3 different. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-06vm: avoid using find_vma_prev() unnecessarilyLinus Torvalds
Several users of "find_vma_prev()" were not in fact interested in the previous vma if there was no primary vma to be found either. And in those cases, we're much better off just using the regular "find_vma()", and then "prev" can be looked up by just checking vma->vm_prev. The find_vma_prev() semantics are fairly subtle (see Mikulas' recent commit 83cd904d271b: "mm: fix find_vma_prev"), and the whole "return prev by reference" means that it generates worse code too. Thus this "let's avoid using this inconvenient and clearly too subtle interface when we don't really have to" patch. Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-06mm: fix find_vma_prevMikulas Patocka
Commit 6bd4837de96e ("mm: simplify find_vma_prev()") broke memory management on PA-RISC. After application of the patch, programs that allocate big arrays on the stack crash with segfault, for example, this will crash if compiled without optimization: int main() { char array[200000]; array[199999] = 0; return 0; } The reason is that PA-RISC has up-growing stack and the stack is usually the last memory area. In the above example, a page fault happens above the stack. Previously, if we passed too high address to find_vma_prev, it returned NULL and stored the last VMA in *pprev. After "simplify find_vma_prev" change, it stores NULL in *pprev. Consequently, the stack area is not found and it is not expanded, as it used to be before the change. This patch restores the old behavior and makes it return the last VMA in *pprev if the requested address is higher than address of any other VMA. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-06mmap: EINVAL not ENOMEM when rejecting VM_GROWSHugh Dickins
Currently error is -ENOMEM when rejecting VM_GROWSDOWN|VM_GROWSUP from shared anonymous: hoist the file case's -EINVAL up for both. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-06page_cgroup: fix horrid swap accounting regressionHugh Dickins
Why is memcg's swap accounting so broken? Insane counts, wrong ownership, unfreeable structures, which later get freed and then accessed after free. Turns out to be a tiny a little 3.3-rc1 regression in 9fb4b7cc0724 "page_cgroup: add helper function to get swap_cgroup": the helper function (actually named lookup_swap_cgroup()) returns an address using void* arithmetic, but the structure in question is a short. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Bob Liu <lliubbo@gmail.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05Merge branch 'akpm' (Andrew's patch bomb)Linus Torvalds
Merge the emailed seties of 19 patches from Andrew Morton * akpm: rapidio/tsi721: fix queue wrapping bug in inbound doorbell handler memcg: fix mapcount check in move charge code for anonymous page mm: thp: fix BUG on mm->nr_ptes alpha: fix 32/64-bit bug in futex support memcg: fix GPF when cgroup removal races with last exit debugobjects: Fix selftest for static warnings floppy/scsi: fix setting of BIO flags memcg: fix deadlock by inverting lrucare nesting drivers/rtc/rtc-r9701.c: fix crash in r9701_remove() c2port: class_create() returns an ERR_PTR pps: class_create() returns an ERR_PTR, not NULL hung_task: fix the broken rcu_lock_break() logic vfork: kill PF_STARTING coredump_wait: don't call complete_vfork_done() vfork: make it killable vfork: introduce complete_vfork_done() aio: wake up waiters when freeing unused kiocbs kprobes: return proper error code from register_kprobe() kmsg_dump: don't run on non-error paths by default
2012-03-05memcg: fix mapcount check in move charge code for anonymous pageNaoya Horiguchi
Currently the charge on shared anonyous pages is supposed not to moved in task migration. To implement this, we need to check that mapcount > 1, instread of > 2. So this patch fixes it. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05mm: thp: fix BUG on mm->nr_ptesAndrea Arcangeli
Dave Jones reports a few Fedora users hitting the BUG_ON(mm->nr_ptes...) in exit_mmap() recently. Quoting Hugh's discovery and explanation of the SMP race condition: "mm->nr_ptes had unusual locking: down_read mmap_sem plus page_table_lock when incrementing, down_write mmap_sem (or mm_users 0) when decrementing; whereas THP is careful to increment and decrement it under page_table_lock. Now most of those paths in THP also hold mmap_sem for read or write (with appropriate checks on mm_users), but two do not: when split_huge_page() is called by hwpoison_user_mappings(), and when called by add_to_swap(). It's conceivable that the latter case is responsible for the exit_mmap() BUG_ON mm->nr_ptes that has been reported on Fedora." The simplest way to fix it without having to alter the locking is to make split_huge_page() a noop in nr_ptes terms, so by counting the preallocated pagetables that exists for every mapped hugepage. It was an arbitrary choice not to count them and either way is not wrong or right, because they are not used but they're still allocated. Reported-by: Dave Jones <davej@redhat.com> Reported-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Josh Boyer <jwboyer@redhat.com> Cc: <stable@vger.kernel.org> [3.0.x, 3.1.x, 3.2.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05memcg: fix GPF when cgroup removal races with last exitHugh Dickins
When moving tasks from old memcg (with move_charge_at_immigrate on new memcg), followed by removal of old memcg, hit General Protection Fault in mem_cgroup_lru_del_list() (called from release_pages called from free_pages_and_swap_cache from tlb_flush_mmu from tlb_finish_mmu from exit_mmap from mmput from exit_mm from do_exit). Somewhat reproducible, takes a few hours: the old struct mem_cgroup has been freed and poisoned by SLAB_DEBUG, but mem_cgroup_lru_del_list() is still trying to update its stats, and take page off lru before freeing. A task, or a charge, or a page on lru: each secures a memcg against removal. In this case, the last task has been moved out of the old memcg, and it is exiting: anonymous pages are uncharged one by one from the memcg, as they are zapped from its pagetables, so the charge gets down to 0; but the pages themselves are queued in an mmu_gather for freeing. Most of those pages will be on lru (and force_empty is careful to lru_add_drain_all, to add pages from pagevec to lru first), but not necessarily all: perhaps some have been isolated for page reclaim, perhaps some isolated for other reasons. So, force_empty may find no task, no charge and no page on lru, and let the removal proceed. There would still be no problem if these pages were immediately freed; but typically (and the put_page_testzero protocol demands it) they have to be added back to lru before they are found freeable, then removed from lru and freed. We don't see the issue when adding, because the mem_cgroup_iter() loops keep their own reference to the memcg being scanned; but when it comes to mem_cgroup_lru_del_list(). I believe this was not an issue in v3.2: there, PageCgroupAcctLRU and PageCgroupUsed flags were used (like a trick with mirrors) to deflect view of pc->mem_cgroup to the stable root_mem_cgroup when neither set. 38c5d72f3ebe ("memcg: simplify LRU handling by new rule") mercifully removed those convolutions, but left this General Protection Fault. But it's surprisingly easy to restore the old behaviour: just check PageCgroupUsed in mem_cgroup_lru_add_list() (which decides on which lruvec to add), and reset pc to root_mem_cgroup if page is uncharged. A risky change? just going back to how it worked before; testing, and an audit of uses of pc->mem_cgroup, show no problem. And there's a nice bonus: with mem_cgroup_lru_add_list() itself making sure that an uncharged page goes to root lru, mem_cgroup_reset_owner() no longer has any purpose, and we can safely revert 4e5f01c2b9b9 ("memcg: clear pc->mem_cgroup if necessary"). Calling update_page_reclaim_stat() after add_page_to_lru_list() in swap.c is not strictly necessary: the lru_lock there, with RCU before memcg structures are freed, makes mem_cgroup_get_reclaim_stat_from_page safe without that; but it seems cleaner to rely on one dependency less. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05memcg: fix deadlock by inverting lrucare nestingHugh Dickins
We have forgotten the rules of lock nesting: the irq-safe ones must be taken inside the non-irq-safe ones, otherwise we are open to deadlock: CPU0 CPU1 ---- ---- lock(&(&pc->lock)->rlock); local_irq_disable(); lock(&(&zone->lru_lock)->rlock); lock(&(&pc->lock)->rlock); <Interrupt> lock(&(&zone->lru_lock)->rlock); To check a different locking issue, I happened to add a spin_lock to memcg's bit_spin_lock in lock_page_cgroup(), and lockdep very quickly complained about __mem_cgroup_commit_charge_lrucare() (on CPU1 above). So delete __mem_cgroup_commit_charge_lrucare(), passing a bool lrucare to __mem_cgroup_commit_charge() instead, taking zone->lru_lock under lock_page_cgroup() in the lrucare case. The original was using spin_lock_irqsave, but we'd be in more trouble if it were ever called at interrupt time: unconditional _irq is enough. And ClearPageLRU before del from lru, SetPageLRU before add to lru: no strong reason, but that is the ordering used consistently elsewhere. Fixes 36b62ad539498d00c2d280a151a ("memcg: simplify corner case handling of LRU"). Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05Merge branch 'for-3.3-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu Pull per-cpu patches from Tejun Heo: "This pull request contains four patches. One replaces manual clearing with bitmap_clear(), two fix generic definition of __this_cpu ops so that they don't choose unnecessarily strict arch version. One makes _this_cpu definition use raw_local_irq_*() so that it doesn't end up wrecking irq on/off state tracking when used from inside lockdep. Of the four patches, the raw_local_irq_*() update is the most important, so please feel free to cherry pick only that one patch and ignore the rest if you want to - commit e920d5971d 'percpu: use raw_local_irq_* in _this_cpu op'." * 'for-3.3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: percpu: fix __this_cpu_{sub,inc,dec}_return() definition percpu: use raw_local_irq_* in _this_cpu op percpu: fix generic definition of __this_cpu_add_and_return() percpu: use bitmap_clear
2012-03-05flush_tlb_range() needs ->page_table_lock when ->mmap_sem is not heldAl Viro
All other callers already hold either ->mmap_sem (exclusive) or ->page_table_lock. And we need it because some page table flushing instanced do work explicitly with ge tables. See e.g. arch/powerpc/mm/tlb_hash32.c, flush_tlb_range() and flush_range() in there. The same goes for uml, with a lot more extensive playing with page tables. Almost all callers are actually fine - flush_tlb_range() may have no need to bother playing with page tables, but it can do so safely; again, this caller is the sole exception - everything else either has exclusive ->mmap_sem on the mm in question, or mm->page_table_lock is held. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-05VM_GROWS{UP,DOWN} shouldn't be set on shmem VMAsAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-01memblock: Fix size aligning of memblock_alloc_base_nid()Tejun Heo
memblock allocator aligns @size to @align to reduce the amount of fragmentation. Commit: 7bd0b0f0da ("memblock: Reimplement memblock allocation using reverse free area iterator") Broke it by incorrectly relocating @size aligning to memblock_find_in_range_node(). As the aligned size is not propagated back to memblock_alloc_base_nid(), the actually reserved size isn't aligned. While this increases memory use for memblock reserved array, this shouldn't cause any critical failure; however, it seems that the size aligning was hiding a use-beyond-allocation bug in sparc64 and losing the aligning causes boot failure. The underlying problem is currently being debugged but this is a proper fix in itself, it's already pretty late in -rc cycle for boot failures and reverting the change for debugging isn't difficult. Restore the size aligning moving it to memblock_alloc_base_nid(). Reported-by: Meelis Roos <mroos@linux.ee> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: David S. Miller <davem@davemloft.net> Cc: Grant Likely <grant.likely@secretlab.ca> Cc: Rob Herring <rob.herring@calxeda.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20120228205621.GC3252@dhcp-172-17-108-109.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <alpine.SOC.1.00.1202130942030.1488@math.ut.ee>
2012-02-24NOMMU: Don't need to clear vm_mm when deleting a VMADavid Howells
Don't clear vm_mm in a deleted VMA as it's unnecessary and might conceivably break the filesystem or driver VMA close routine. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-24NOMMU: Lock i_mmap_mutex for access to the VMA prio listDavid Howells
Lock i_mmap_mutex for access to the VMA prio list to prevent concurrent access. Currently, certain parts of the mmap handling are protected by the region mutex, but not all. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-24mm: memcg: Correct unregistring of events attached to the same eventfdAnton Vorontsov
There is an issue when memcg unregisters events that were attached to the same eventfd: - On the first call mem_cgroup_usage_unregister_event() removes all events attached to a given eventfd, and if there were no events left, thresholds->primary would become NULL; - Since there were several events registered, cgroups core will call mem_cgroup_usage_unregister_event() again, but now kernel will oops, as the function doesn't expect that threshold->primary may be NULL. That's a good question whether mem_cgroup_usage_unregister_event() should actually remove all events in one go, but nowadays it can't do any better as cftype->unregister_event callback doesn't pass any private event-associated cookie. So, let's fix the issue by simply checking for threshold->primary. FWIW, w/o the patch the following oops may be observed: BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0 Pid: 574, comm: kworker/0:2 Not tainted 3.3.0-rc4+ #9 Bochs Bochs RIP: 0010:[<ffffffff810be32c>] [<ffffffff810be32c>] mem_cgroup_usage_unregister_event+0x9c/0x1f0 RSP: 0018:ffff88001d0b9d60 EFLAGS: 00010246 Process kworker/0:2 (pid: 574, threadinfo ffff88001d0b8000, task ffff88001de91cc0) Call Trace: [<ffffffff8107092b>] cgroup_event_remove+0x2b/0x60 [<ffffffff8103db94>] process_one_work+0x174/0x450 [<ffffffff8103e413>] worker_thread+0x123/0x2d0 Cc: stable <stable@vger.kernel.org> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-13vfs: fix panic in __d_lookup() with high dentry hashtable countsDimitri Sivanich
When the number of dentry cache hash table entries gets too high (2147483648 entries), as happens by default on a 16TB system, use of a signed integer in the dcache_init() initialization loop prevents the dentry_hashtable from getting initialized, causing a panic in __d_lookup(). Fix this in dcache_init() and similar areas. Signed-off-by: Dimitri Sivanich <sivanich@sgi.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-02-10Merge tag 'writeback-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux fix 1 mysterious divide error fix 3 NULL dereference bugs in writeback tracing, on SD card removal w/o umount * tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux: writeback: fix dereferencing NULL bdi->dev on trace_writeback_queue lib: proportion: lower PROP_MAX_SHIFT to 32 on 64-bit kernel writeback: fix NULL bdi->dev in trace writeback_single_inode backing-dev: fix wakeup timer races with bdi_unregister()
2012-02-08mm: fix UP THP spin_is_locked BUGsHugh Dickins
Fix CONFIG_TRANSPARENT_HUGEPAGE=y CONFIG_SMP=n CONFIG_DEBUG_VM=y CONFIG_DEBUG_SPINLOCK=n kernel: spin_is_locked() is then always false, and so triggers some BUGs in Transparent HugePage codepaths. asm-generic/bug.h mentions this problem, and provides a WARN_ON_SMP(x); but being too lazy to add VM_BUG_ON_SMP, BUG_ON_SMP, WARN_ON_SMP_ONCE, VM_WARN_ON_SMP_ONCE, just test NR_CPUS != 1 in the existing VM_BUG_ONs. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-08mm: compaction: check for overlapping nodes during isolation for migrationMel Gorman
When isolating pages for migration, migration starts at the start of a zone while the free scanner starts at the end of the zone. Migration avoids entering a new zone by never going beyond the free scanned. Unfortunately, in very rare cases nodes can overlap. When this happens, migration isolates pages without the LRU lock held, corrupting lists which will trigger errors in reclaim or during page free such as in the following oops BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: [<ffffffff810f795c>] free_pcppages_bulk+0xcc/0x450 PGD 1dda554067 PUD 1e1cb58067 PMD 0 Oops: 0000 [#1] SMP CPU 37 Pid: 17088, comm: memcg_process_s Tainted: G X RIP: free_pcppages_bulk+0xcc/0x450 Process memcg_process_s (pid: 17088, threadinfo ffff881c2926e000, task ffff881c2926c0c0) Call Trace: free_hot_cold_page+0x17e/0x1f0 __pagevec_free+0x90/0xb0 release_pages+0x22a/0x260 pagevec_lru_move_fn+0xf3/0x110 putback_lru_page+0x66/0xe0 unmap_and_move+0x156/0x180 migrate_pages+0x9e/0x1b0 compact_zone+0x1f3/0x2f0 compact_zone_order+0xa2/0xe0 try_to_compact_pages+0xdf/0x110 __alloc_pages_direct_compact+0xee/0x1c0 __alloc_pages_slowpath+0x370/0x830 __alloc_pages_nodemask+0x1b1/0x1c0 alloc_pages_vma+0x9b/0x160 do_huge_pmd_anonymous_page+0x160/0x270 do_page_fault+0x207/0x4c0 page_fault+0x25/0x30 The "X" in the taint flag means that external modules were loaded but but is unrelated to the bug triggering. The real problem was because the PFN layout looks like this Zone PFN ranges: DMA 0x00000010 -> 0x00001000 DMA32 0x00001000 -> 0x00100000 Normal 0x00100000 -> 0x01e80000 Movable zone start PFN for each node early_node_map[14] active PFN ranges 0: 0x00000010 -> 0x0000009b 0: 0x00000100 -> 0x0007a1ec 0: 0x0007a354 -> 0x0007a379 0: 0x0007f7ff -> 0x0007f800 0: 0x00100000 -> 0x00680000 1: 0x00680000 -> 0x00e80000 0: 0x00e80000 -> 0x01080000 1: 0x01080000 -> 0x01280000 0: 0x01280000 -> 0x01480000 1: 0x01480000 -> 0x01680000 0: 0x01680000 -> 0x01880000 1: 0x01880000 -> 0x01a80000 0: 0x01a80000 -> 0x01c80000 1: 0x01c80000 -> 0x01e80000 The fix is straight-forward. isolate_migratepages() has to make a similar check to isolate_freepage to ensure that it never isolates pages from a zone it does not hold the LRU lock for. This was discovered in a 3.0-based kernel but it affects 3.1.x, 3.2.x and current mainline. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Michal Nazarewicz <mina86@mina86.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-04Merge branch 'akpm'Linus Torvalds
* akpm: mm: compaction: check pfn_valid when entering a new MAX_ORDER_NR_PAGES block during isolation for migration readahead: fix pipeline break caused by block plug kprobes: fix a memory leak in function pre_handler_kretprobe() drivers/tty/vt/vt_ioctl.c: fix KDFONTOP 32bit compatibility layer lkdtm: avoid calling lkdtm_do_action() with spinlock held mm/filemap_xip.c: fix race condition in xip_file_fault() mm/memcontrol.c: fix warning with CONFIG_NUMA=n avr32: select generic atomic64_t support mm: postpone migrated page mapping reset xtensa: fix memscan() MAINTAINERS: update lguest F: patterns MAINTAINERS: remove staging sections MAINTAINERS: remove iMX5 section MAINTAINERS: update partitions block F: patterns
2012-02-03mm: compaction: check pfn_valid when entering a new MAX_ORDER_NR_PAGES block ↵Mel Gorman
during isolation for migration When isolating for migration, migration starts at the start of a zone which is not necessarily pageblock aligned. Further, it stops isolating when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally not aligned. This allows isolate_migratepages() to call pfn_to_page() on an invalid PFN which can result in a crash. This was originally reported against a 3.0-based kernel with the following trace in a crash dump. PID: 9902 TASK: d47aecd0 CPU: 0 COMMAND: "memcg_process_s" #0 [d72d3ad0] crash_kexec at c028cfdb #1 [d72d3b24] oops_end at c05c5322 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60 #3 [d72d3bec] bad_area at c0227fb6 #4 [d72d3c00] do_page_fault at c05c72ec #5 [d72d3c80] error_code (via page_fault) at c05c47a4 EAX: 00000000 EBX: 000c0000 ECX: 00000001 EDX: 00000807 EBP: 000c0000 DS: 007b ESI: 00000001 ES: 007b EDI: f3000a80 GS: 6f50 CS: 0060 EIP: c030b15a ERR: ffffffff EFLAGS: 00010002 #6 [d72d3cb4] isolate_migratepages at c030b15a #7 [d72d3d14] zone_watermark_ok at c02d26cb #8 [d72d3d2c] compact_zone at c030b8de #9 [d72d3d68] compact_zone_order at c030bba1 #10 [d72d3db4] try_to_compact_pages at c030bc84 #11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7 #12 [d72d3e08] __alloc_pages_slowpath at c02d66c7 #13 [d72d3e78] __alloc_pages_nodemask at c02d6a97 #14 [d72d3eb8] alloc_pages_vma at c030a845 #15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb #16 [d72d3f00] handle_mm_fault at c02f36c6 #17 [d72d3f30] do_page_fault at c05c70ed #18 [d72d3fb0] error_code (via page_fault) at c05c47a4 EAX: b71ff000 EBX: 00000001 ECX: 00001600 EDX: 00000431 DS: 007b ESI: 08048950 ES: 007b EDI: bfaa3788 SS: 007b ESP: bfaa36e0 EBP: bfaa3828 GS: 6f50 CS: 0073 EIP: 080487c8 ERR: ffffffff EFLAGS: 00010202 It was also reported by Herbert van den Bergh against 3.1-based kernel with the following snippet from the console log. BUG: unable to handle kernel paging request at 01c00008 IP: [<c0522399>] isolate_migratepages+0x119/0x390 *pdpt = 000000002f7ce001 *pde = 0000000000000000 It is expected that it also affects 3.2.x and current mainline. The problem is that pfn_valid is only called on the first PFN being checked and that PFN is not necessarily aligned. Lets say we have a case like this H = MAX_ORDER_NR_PAGES boundary | = pageblock boundary m = cc->migrate_pfn f = cc->free_pfn o = memory hole H------|------H------|----m-Hoooooo|ooooooH-f----|------H The migrate_pfn is just below a memory hole and the free scanner is beyond the hole. When isolate_migratepages started, it scans from migrate_pfn to migrate_pfn+pageblock_nr_pages which is now in a memory hole. It checks pfn_valid() on the first PFN but then scans into the hole where there are not necessarily valid struct pages. This patch ensures that isolate_migratepages calls pfn_valid when necessary. Reported-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Tested-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Michal Nazarewicz <mina86@mina86.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-03readahead: fix pipeline break caused by block plugShaohua Li
Herbert Poetzl reported a performance regression since 2.6.39. The test is a simple dd read, but with big block size. The reason is: T1: ra (A, A+128k), (A+128k, A+256k) T2: lock_page for page A, submit the 256k T3: hit page A+128K, ra (A+256k, A+384). the range isn't submitted because of plug and there isn't any lock_page till we hit page A+256k because all pages from A to A+256k is in memory T4: hit page A+256k, ra (A+384, A+ 512). Because of plug, the range isn't submitted again. T5: lock_page A+256k, so (A+256k, A+512k) will be submitted. The task is waitting for (A+256k, A+512k) finish. There is no request to disk in T3 and T4, so readahead pipeline breaks. We really don't need block plug for generic_file_aio_read() for buffered I/O. The readahead already has plug and has fine grained control when I/O should be submitted. Deleting plug for buffered I/O fixes the regression. One side effect is plug makes the request size 256k, the size is 128k without it. This is because default ra size is 128k and not a reason we need plug here. Vivek said: : We submit some readahead IO to device request queue but because of nested : plug, queue never gets unplugged. When read logic reaches a page which is : not in page cache, it waits for page to be read from the disk : (lock_page_killable()) and that time we flush the plug list. : : So effectively read ahead logic is kind of broken in parts because of : nested plugging. Removing top level plug (generic_file_aio_read()) for : buffered reads, will allow unplugging queue earlier for readahead. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Reported-by: Herbert Poetzl <herbert@13thfloor.at> Tested-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-03mm/filemap_xip.c: fix race condition in xip_file_fault()Carsten Otte
Fix a race condition that shows in conjunction with xip_file_fault() when two threads of the same user process fault on the same memory page. In this case, the race winner will install the page table entry and the unlucky loser will cause an oops: xip_file_fault calls vm_insert_pfn (via vm_insert_mixed) which drops out at this check: retval = -EBUSY; if (!pte_none(*pte)) goto out_unlock; The resulting -EBUSY return value will trigger a BUG_ON() in xip_file_fault. This fix simply considers the fault as fixed in this case, because the race winner has successfully installed the pte. [akpm@linux-foundation.org: use conventional (and consistent) comment layout] Reported-by: David Sadler <dsadler@us.ibm.com> Signed-off-by: Carsten Otte <cotte@de.ibm.com> Reported-by: Louis Alex Eisner <leisner@cs.ucsd.edu> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-03mm/memcontrol.c: fix warning with CONFIG_NUMA=nAndrew Morton
mm/memcontrol.c: In function 'memcg_check_events': mm/memcontrol.c:779: warning: unused variable 'do_numainfo' Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Hiroyuki KAMEZAWA <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-03mm: postpone migrated page mapping resetKonstantin Khlebnikov
Postpone resetting page->mapping until the final remove_migration_ptes(). Otherwise the expression PageAnon(migration_entry_to_page(entry)) does not work. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-03Merge tag 'kmemleak-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux Trivial kmemleak bug-fixes: - Early logging doesn't stop when kmemleak is off by default. - Zero-size scanning areas should be ignored (currently it prints a warning). * tag 'kmemleak-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux: kmemleak: Disable early logging when kmemleak is off by default kmemleak: Only scan non-zero-size areas
2012-02-02Fix race in process_vm_rw_coreChristopher Yeoh
This fixes the race in process_vm_core found by Oleg (see http://article.gmane.org/gmane.linux.kernel/1235667/ for details). This has been updated since I last sent it as the creation of the new mm_access() function did almost exactly the same thing as parts of the previous version of this patch did. In order to use mm_access() even when /proc isn't enabled, we move it to kernel/fork.c where other related process mm access functions already are. Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-01backing-dev: fix wakeup timer races with bdi_unregister()Rabin Vincent
While 7a401a972df8e18 ("backing-dev: ensure wakeup_timer is deleted") addressed the problem of the bdi being freed with a queued wakeup timer, there are other races that could happen if the wakeup timer expires after/during bdi_unregister(), before bdi_destroy() is called. wakeup_timer_fn() could attempt to wakeup a task which has already has been freed, or could access a NULL bdi->dev via the wake_forker_thread tracepoint. Cc: <stable@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Reported-by: Chanho Min <chanho.min@lge.com> Reviewed-by: Namjae Jeon <linkinjeon@gmail.com> Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2012-01-26Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: rcu: Add missing __cpuinit annotation in rcutorture code sched: Add "const" to is_idle_task() parameter rcu: Make rcutorture bool parameters really bool (core code) memblock: Fix alloc failure due to dumb underflow protection in memblock_find_in_range_node()
2012-01-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
Davem says: 1) Fix JIT code generation on x86-64 for divide by zero, from Eric Dumazet. 2) tg3 header length computation correction from Eric Dumazet. 3) More build and reference counting fixes for socket memory cgroup code from Glauber Costa. 4) module.h snuck back into a core header after all the hard work we did to remove that, from Paul Gortmaker and Jesper Dangaard Brouer. 5) Fix PHY naming regression and add some new PCI IDs in stmmac, from Alessandro Rubini. 6) Netlink message generation fix in new team driver, should only advertise the entries that changed during events, from Jiri Pirko. 7) SRIOV VF registration and unregistration fixes, and also add a missing PCI ID, from Roopa Prabhu. 8) Fix infinite loop in tx queue flush code of brcmsmac, from Stanislaw Gruszka. 9) ftgmac100/ftmac100 build fix, missing interrupt.h include. 10) Memory leak fix in net/hyperv do_set_mutlicast() handling, from Wei Yongjun. 11) Off by one fix in netem packet scheduler, from Vijay Subramanian. 12) TCP loss detection fix from Yuchung Cheng. 13) TCP reset packet MD5 calculation uses wrong address, fix from Shawn Lu. 14) skge carrier assertion and DMA mapping fixes from Stephen Hemminger. 15) Congestion recovery undo performed at the wrong spot in BIC and CUBIC congestion control modules, fix from Neal Cardwell. 16) Ethtool ETHTOOL_GSSET_INFO is unnecessarily restrictive, from Michał Mirosław. 17) Fix triggerable race in ipv6 sysctl handling, from Francesco Ruggeri. 18) Statistics bug fixes in mlx4 from Eugenia Emantayev. 19) rds locking bug fix during info dumps, from your's truly. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (67 commits) rds: Make rds_sock_lock BH rather than IRQ safe. netprio_cgroup.h: dont include module.h from other includes net: flow_dissector.c missing include linux/export.h team: send only changed options/ports via netlink net/hyperv: fix possible memory leak in do_set_multicast() drivers/net: dsa/mv88e6xxx.c files need linux/module.h stmmac: added PCI identifiers llc: Fix race condition in llc_ui_recvmsg stmmac: fix phy naming inconsistency dsa: Add reporting of silicon revision for Marvell 88E6123/88E6161/88E6165 switches. tg3: fix ipv6 header length computation skge: add byte queue limit support mv643xx_eth: Add Rx Discard and Rx Overrun statistics bnx2x: fix compilation error with SOE in fw_dump bnx2x: handle CHIP_REVISION during init_one bnx2x: allow user to change ring size in ISCSI SD mode bnx2x: fix Big-Endianess in ethtool -t bnx2x: fixed ethtool statistics for MF modes bnx2x: credit-leakage fixup on vlan_mac_del_all macvlan: fix a possible use after free ...
2012-01-23mm: fix rss count leakage during migrationKonstantin Khlebnikov
Memory migration fills a pte with a migration entry and it doesn't update the rss counters. Then it replaces the migration entry with the new page (or the old one if migration failed). But between these two passes this pte can be unmaped, or a task can fork a child and it will get a copy of this migration entry. Nobody accounts for this in the rss counters. This patch properly adjust rss counters for migration entries in zap_pte_range() and copy_one_pte(). Thus we avoid extra atomic operations on the migration fast-path. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23SHM_UNLOCK: fix Unevictable pages stranded after swapHugh Dickins
Commit cc39c6a9bbde ("mm: account skipped entries to avoid looping in find_get_pages") correctly fixed an infinite loop; but left a problem that find_get_pages() on shmem would return 0 (appearing to callers to mean end of tree) when it meets a run of nr_pages swap entries. The only uses of find_get_pages() on shmem are via pagevec_lookup(), called from invalidate_mapping_pages(), and from shmctl SHM_UNLOCK's scan_mapping_unevictable_pages(). The first is already commented, and not worth worrying about; but the second can leave pages on the Unevictable list after an unusual sequence of swapping and locking. Fix that by using shmem_find_get_pages_and_swap() (then ignoring the swap) instead of pagevec_lookup(). But I don't want to contaminate vmscan.c with shmem internals, nor shmem.c with LRU locking. So move scan_mapping_unevictable_pages() into shmem.c, renaming it shmem_unlock_mapping(); and rename check_move_unevictable_page() to check_move_unevictable_pages(), looping down an array of pages, oftentimes under the same lock. Leave out the "rotate unevictable list" block: that's a leftover from when this was used for /proc/sys/vm/scan_unevictable_pages, whose flawed handling involved looking at pages at tail of LRU. Was there significance to the sequence first ClearPageUnevictable, then test page_evictable, then SetPageUnevictable here? I think not, we're under LRU lock, and have no barriers between those. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michel Lespinasse <walken@google.com> Cc: <stable@vger.kernel.org> [back to 3.1 but will need respins] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23SHM_UNLOCK: fix long unpreemptible sectionHugh Dickins
scan_mapping_unevictable_pages() is used to make SysV SHM_LOCKed pages evictable again once the shared memory is unlocked. It does this with pagevec_lookup()s across the whole object (which might occupy most of memory), and takes 300ms to unlock 7GB here. A cond_resched() every PAGEVEC_SIZE pages would be good. However, KOSAKI-san points out that this is called under shmem.c's info->lock, and it's also under shm.c's shm_lock(), both spinlocks. There is no strong reason for that: we need to take these pages off the unevictable list soonish, but those locks are not required for it. So move the call to scan_mapping_unevictable_pages() from shmem.c's unlock handling up to shm.c's unlock handling. Remove the recently added barrier, not needed now we have spin_unlock() before the scan. Use get_file(), with subsequent fput(), to make sure we have a reference to mapping throughout scan_mapping_unevictable_pages(): that's something that was previously guaranteed by the shm_lock(). Remove shmctl's lru_add_drain_all(): we don't fault in pages at SHM_LOCK time, and we lazily discover them to be Unevictable later, so it serves no purpose for SHM_LOCK; and serves no purpose for SHM_UNLOCK, since pages still on pagevec are not marked Unevictable. The original code avoided redundant rescans by checking VM_LOCKED flag at its level: now avoid them by checking shp's SHM_LOCKED. The original code called scan_mapping_unevictable_pages() on a locked area at shm_destroy() time: perhaps we once had accounting cross-checks which required that, but not now, so skip the overhead and just let inode eviction deal with them. Put check_move_unevictable_page() and scan_mapping_unevictable_pages() under CONFIG_SHMEM (with stub for the TINY case when ramfs is used), more as comment than to save space; comment them used for SHM_UNLOCK. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23mm/hugetlb.c: undo change to page mapcount in fault handlerHillf Danton
Page mapcount should be updated only if we are sure that the page ends up in the page table otherwise we would leak if we couldn't COW due to reservations or if idx is out of bounds. Signed-off-by: Hillf Danton <dhillf@gmail.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23mm: memcg: update the correct soft limit tree during migrationJohannes Weiner
end_migration() passes the old page instead of the new page to commit the charge. This page descriptor is not used for committing itself, though, since we also pass the (correct) page_cgroup descriptor. But it's used to find the soft limit tree through the page's zone, so the soft limit tree of the old page's zone is updated instead of that of the new page's, which might get slightly out of date until the next charge reaches the ratelimit point. This glitch has been present since 5564e88 ("memcg: condense page_cgroup-to-page lookup points"). This fixes a bug that I introduced in 2.6.38. It's benign enough (to my knowledge) that we probably don't want this for stable. Reported-by: Hugh Dickins <hughd@google.com> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23mm: __count_immobile_pages(): make sure the node is onlineMichal Hocko
page_zone() requires an online node otherwise we are accessing NULL NODE_DATA. This is not an issue at the moment because node_zones are located at the structure beginning but this might change in the future so better be careful about that. Signed-off-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23mm: fix NULL ptr dereference in __count_immobile_pagesMichal Hocko
Fix the following NULL ptr dereference caused by cat /sys/devices/system/memory/memory0/removable Pid: 13979, comm: sed Not tainted 3.0.13-0.5-default #1 IBM BladeCenter LS21 -[7971PAM]-/Server Blade RIP: __count_immobile_pages+0x4/0x100 Process sed (pid: 13979, threadinfo ffff880221c36000, task ffff88022e788480) Call Trace: is_pageblock_removable_nolock+0x34/0x40 is_mem_section_removable+0x74/0xf0 show_mem_removable+0x41/0x70 sysfs_read_file+0xfe/0x1c0 vfs_read+0xc7/0x130 sys_read+0x53/0xa0 system_call_fastpath+0x16/0x1b We are crashing because we are trying to dereference NULL zone which came from pfn=0 (struct page ffffea0000000000). According to the boot log this page is marked reserved: e820 update range: 0000000000000000 - 0000000000010000 (usable) ==> (reserved) and early_node_map confirms that: early_node_map[3] active PFN ranges 1: 0x00000010 -> 0x0000009c 1: 0x00000100 -> 0x000bffa3 1: 0x00100000 -> 0x00240000 The problem is that memory_present works in PAGE_SECTION_MASK aligned blocks so the reserved range sneaks into the the section as well. This also means that free_area_init_node will not take care of those reserved pages and they stay uninitialized. When we try to read the removable status we walk through all available sections and hope that the zone is valid for all pages in the section. But this is not true in this case as the zone and nid are not initialized. We have only one node in this particular case and it is marked as node=1 (rather than 0) and that made the problem visible because page_to_nid will return 0 and there are no zones on the node. Let's check that the zone is valid and that the given pfn falls into its boundaries and mark the section not removable. This might cause some false positives, probably, but we do not have any sane way to find out whether the page is reserved by the platform or it is just not used for whatever other reasons. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-22net: fix socket memcg build with !CONFIG_NETGlauber Costa
There is still a build bug with the sock memcg code, that triggers with !CONFIG_NET, that survived my series of randconfig builds. Signed-off-by: Glauber Costa <glommer@parallels.com> Reported-by: Randy Dunlap <rdunlap@xenotime.net> CC: Hiroyouki Kamezawa <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-01-20percpu: use bitmap_clearAkinobu Mita
Use bitmap_clear rather than clearing individual bits in a memory region. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: Tejun Heo <tj@kernel.org>
2012-01-20kmemleak: Disable early logging when kmemleak is off by defaultCatalin Marinas
Commit b6693005 (kmemleak: When the early log buffer is exceeded, report the actual number) deferred the disabling of the early logging to kmemleak_init(). However, when CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y, the early logging was no longer disabled causing __init kmemleak functions to be called even after the kernel freed the init memory. This patch disables the early logging during kmemleak_init() if kmemleak is left disabled. Reported-by: Dirk Gouders <gouders@et.bocholt.fh-gelsenkirchen.de> Tested-by: Dirk Gouders <gouders@et.bocholt.fh-gelsenkirchen.de> Tested-by: Josh Boyer <jwboyer@gmail.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2012-01-20kmemleak: Only scan non-zero-size areasTiejun Chen
Kmemleak should only track valid scan areas with a non-zero size. Otherwise, such area may reside just at the end of an object and kmemleak would report "Adding scan area to unknown object". Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2012-01-17Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (47 commits) tg3: Fix single-vector MSI-X code openvswitch: Fix multipart datapath dumps. ipv6: fix per device IP snmp counters inetpeer: initialize ->redirect_genid in inet_getpeer() net: fix NULL-deref in WARN() in skb_gso_segment() net: WARN if skb_checksum_help() is called on skb requiring segmentation caif: Remove bad WARN_ON in caif_dev caif: Fix typo in Vendor/Product-ID for CAIF modems bnx2x: Disable AN KR work-around for BCM57810 bnx2x: Remove AutoGrEEEn for BCM84833 bnx2x: Remove 100Mb force speed for BCM84833 bnx2x: Fix PFC setting on BCM57840 bnx2x: Fix Super-Isolate mode for BCM84833 net: fix some sparse errors net: kill duplicate included header net: sh-eth: Fix build error by the value which is not defined net: Use device model to get driver name in skb_gso_segment() bridge: BH already disabled in br_fdb_cleanup() net: move sock_update_memcg outside of CONFIG_INET mwl8k: Fixing Sparse ENDIAN CHECK warning ...
2012-01-17net: move sock_update_memcg outside of CONFIG_INETGlauber Costa
Although only used currently for tcp sockets, this function is now used in common sock code (for sock_clone()) Commit 475f1b52645a29936b9df1d8fcd45f7e56bd4a9f moved the declaration of sock_update_clone() to inside sock.c, but this only fixes the problem when CONFIG_CGROUP_MEM_RES_CTLR_KMEM is also not defined. This patch here is verified to fix both problems, although reverting the previous one is not necessary. Signed-off-by: Glauber Costa <glommer@parallels.com> CC: David S. Miller <davem@davemloft.net> CC: Stephen Rothwell <sfr@canb.auug.org.au> Reported-by: Randy Dunlap <rdunlap@xenotime.net> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-01-16memblock: Fix alloc failure due to dumb underflow protection in ↵Tejun Heo
memblock_find_in_range_node() 7bd0b0f0da ("memblock: Reimplement memblock allocation using reverse free area iterator") implemented a simple top-down allocator using a reverse memblock iterator. To avoid underflow in the allocator loop, it simply raised the lower boundary to the requested size under the assumption that requested size would be far smaller than available memblocks. This causes early page table allocation failure under certain configurations in Xen. Fix it by checking for underflow directly instead of bumping up lower bound. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: rjw@sisk.pl Cc: xen-devel@lists.xensource.com Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20120113181412.GA11112@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-14Merge tag 'kmemleak' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux Kmemleak patches Main features: - Handle percpu memory allocations (only scanning them, not actually reporting). - Memory hotplug support. Usability improvements: - Show the origin of early allocations. - Report previously found leaks even if kmemleak has been disabled by some error. * tag 'kmemleak' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux: kmemleak: Add support for memory hotplug kmemleak: Handle percpu memory allocation kmemleak: Report previously found leaks even after an error kmemleak: When the early log buffer is exceeded, report the actual number kmemleak: Show where early_log issues come from
2012-01-12mm/vmalloc.c: eliminate extra loop in pcpu_get_vm_areas error pathKautuk Consul
If either of the vas or vms arrays are not properly kzalloced, then the code jumps to the err_free label. The err_free label runs a loop to check and free each of the array members of the vas and vms arrays which is not required for this situation as none of the array members have been allocated till this point. Eliminate the extra loop we have to go through by introducing a new label err_free2 and then jumping to it. [akpm@linux-foundation.org: remove now-unneeded tests] Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-12mm: rearrange putback_inactive_pagesHugh Dickins
There is sometimes confusion between the global putback_lru_pages() in migrate.c and the static putback_lru_pages() in vmscan.c: rename the latter putback_inactive_pages(): it helps shrink_inactive_list() rather as move_active_pages_to_lru() helps shrink_active_list(). Remove unused scan_control arg from putback_inactive_pages() and from update_isolated_counts(). Move clear_active_flags() inside update_isolated_counts(). Move NR_ISOLATED accounting up into shrink_inactive_list() itself, so the balance is clearer. Do the spin_lock_irq() before calling putback_inactive_pages() and spin_unlock_irq() after return from it, so that it better matches update_isolated_counts() and move_active_pages_to_lru(). Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>