On Fri, Oct 07, 2016 at 07:26:36PM -0400, Jeff Layton wrote:
> Well spotted. Yeah, I think you're right. The assertion is this:
>
> percpu_rwsem_assert_held(&file_rwsem);
>
> I'm guessing this is probably fallout from the lglock to rwsem
> conversion (commit aba376607383).
>
> From a quick glance, I think we probably just need to down_read the
> file_rwsem in locks_remove_lease, prior to taking the flc_lock, and
> release it just afterward.
Correct on all that.
> I do want to go over the code a little more
> closely though to make sure other codepaths aren't missing that lock
> though.
Urg, sorry for missing these, I went through it again and found the
below to be missing.
---
Subject: fs/locks: Add missing file_sem locks
I overlooked a few code-paths that can lead to
locks_delete_global_locks().
Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
diff --git a/fs/locks.c b/fs/locks.c
index 133fb2543d21..c623490863a9 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1604,6 +1604,7 @@ 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(file_inode(filp), &dispose);
list_for_each_entry(fl, &ctx->flc_lease, fl_list) {
@@ -1613,6 +1614,8 @@ 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;
@@ -2522,11 +2525,14 @@ 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);
}
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
