Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking fixes from Ingo Molnar:
 "Two fixes:

   - a file locks fix (missing critical section, bug introduced in this
     merge window)

   - an x86 down_write() stack frame annotation"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking, fs/locks: Add missing file_sem locks
  locking/rwsem/x86: Add stack frame dependency for ____down_write()

2 files changed, 10 insertions, 2 deletions

diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h
index 3d33a719f5c1..a34e0d4b957d 100644
--- a/arch/x86/include/asm/rwsem.h
+++ b/arch/x86/include/asm/rwsem.h
@@ -103,8 +103,10 @@ static inline bool __down_read_trylock(struct rw_semaphore *sem)
 ({                                                      \
         long tmp;                                       \
         struct rw_semaphore* ret;                       \
+        register void *__sp asm(_ASM_SP);               \
+                                                        \
         asm volatile("# beginning down_write\n\t"       \
-                     LOCK_PREFIX "  xadd      %1,(%3)\n\t"      \
+                     LOCK_PREFIX "  xadd      %1,(%4)\n\t"      \
                      /* adds 0xffff0001, returns the old value */ \
                      "  test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" \
                      /* was the active mask 0 before? */\
@@ -112,7 +114,7 @@ static inline bool __down_read_trylock(struct rw_semaphore *sem)
                      "  call " slow_path "\n"           \
                      "1:\n"                             \
                      "# ending down_write"              \
-                     : "+m" (sem->count), "=d" (tmp), "=a" (ret)        \
+                     : "+m" (sem->count), "=d" (tmp), "=a" (ret), "+r" (__sp) \
                      : "a" (sem), "1" (RWSEM_ACTIVE_WRITE_BIAS) \
                      : "memory", "cc");                 \
         ret;                                            \
diff --git a/fs/locks.c b/fs/locks.c
index ce93b416b490..22c5b4aa4961 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1609,6 +1609,7 @@ int fcntl_getlease(struct file *filp)
 
         ctx = smp_load_acquire(&inode->i_flctx);
         if (ctx && !list_empty_careful(&ctx->flc_lease)) {
+                percpu_down_read_preempt_disable(&file_rwsem);
                 spin_lock(&ctx->flc_lock);
                 time_out_leases(inode, &dispose);
                 list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
@@ -1618,6 +1619,8 @@ int fcntl_getlease(struct file *filp)
                         break;
                 }
                 spin_unlock(&ctx->flc_lock);
+                percpu_up_read_preempt_enable(&file_rwsem);
+
                 locks_dispose_list(&dispose);
         }
         return type;
@@ -2529,11 +2532,14 @@ locks_remove_lease(struct file *filp, struct file_lock_context *ctx)
         if (list_empty(&ctx->flc_lease))
                 return;
 
+        percpu_down_read_preempt_disable(&file_rwsem);
         spin_lock(&ctx->flc_lock);
         list_for_each_entry_safe(fl, tmp, &ctx->flc_lease, fl_list)
                 if (filp == fl->fl_file)
                         lease_modify(fl, F_UNLCK, &dispose);
         spin_unlock(&ctx->flc_lock);
+        percpu_up_read_preempt_enable(&file_rwsem);
+
         locks_dispose_list(&dispose);
 }