summaryrefslogtreecommitdiff
path: root/include/linux/pagemap.h
diff options
context:
space:
mode:
authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2017-03-24 14:13:05 +0300
committerIngo Molnar <mingo@kernel.org>2017-03-28 08:23:27 +0200
commit591a3d7c09fa08baff48ad86c2347dbd28a52753 (patch)
tree355ce2dc252363a8f83c692f18022bdc76316e5e /include/linux/pagemap.h
parentf2a6a7050109e0a5c7a84c70aa6010f682b2f1ee (diff)
mm: Fix false-positive VM_BUG_ON() in page_cache_{get,add}_speculative()
0day testing by Fengguang Wu triggered this crash while running Trinity: kernel BUG at include/linux/pagemap.h:151! ... CPU: 0 PID: 458 Comm: trinity-c0 Not tainted 4.11.0-rc2-00251-g2947ba0 #1 ... Call Trace: __get_user_pages_fast() get_user_pages_fast() get_futex_key() futex_requeue() do_futex() SyS_futex() do_syscall_64() entry_SYSCALL64_slow_path() It' VM_BUG_ON() due to false-negative in_atomic(). We call page_cache_get_speculative() with disabled local interrupts. It should be atomic enough. So let's check for disabled interrupts in the VM_BUG_ON() condition too, to resolve this. ( This got triggered by the conversion of the x86 GUP code to the generic GUP code. ) Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: LKP <lkp@01.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170324114709.pcytvyb3d6ajux33@black.fi.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/pagemap.h')
-rw-r--r--include/linux/pagemap.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 84943e8057ef..316a19f6b635 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -148,7 +148,7 @@ static inline int page_cache_get_speculative(struct page *page)
#ifdef CONFIG_TINY_RCU
# ifdef CONFIG_PREEMPT_COUNT
- VM_BUG_ON(!in_atomic());
+ VM_BUG_ON(!in_atomic() && !irqs_disabled());
# endif
/*
* Preempt must be disabled here - we rely on rcu_read_lock doing
@@ -186,7 +186,7 @@ static inline int page_cache_add_speculative(struct page *page, int count)
#if !defined(CONFIG_SMP) && defined(CONFIG_TREE_RCU)
# ifdef CONFIG_PREEMPT_COUNT
- VM_BUG_ON(!in_atomic());
+ VM_BUG_ON(!in_atomic() && !irqs_disabled());
# endif
VM_BUG_ON_PAGE(page_count(page) == 0, page);
page_ref_add(page, count);