3.18-stable review patch. If anyone has any objections, please let me know.
------------------ From: "Kirill A. Shutemov" <[email protected]> [ Upstream commit 591a3d7c09fa08baff48ad86c2347dbd28a52753 ] 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 <[email protected]> Signed-off-by: Kirill A. Shutemov <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Aneesh Kumar K.V <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: LKP <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- include/linux/pagemap.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -146,7 +146,7 @@ static inline int page_cache_get_specula #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 @@ -184,7 +184,7 @@ static inline int page_cache_add_specula #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); atomic_add(count, &page->_count);
