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| author |   Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2017-03-24 14:13:05 +0300 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2017-03-28 08:23:27 +0200 |
| commit | 591a3d7c09fa08baff48ad86c2347dbd28a52753 (patch) | |
| tree | 355ce2dc252363a8f83c692f18022bdc76316e5e /include/linux/pagemap.h | |
| parent | x86: Convert the rest of the code to support p4d_t (diff) | |
| download | wireguard-linux-591a3d7c09fa08baff48ad86c2347dbd28a52753.tar.xz wireguard-linux-591a3d7c09fa08baff48ad86c2347dbd28a52753.zip | |
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.h | 4 |
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); |