[v6,5/6] loop: be paranoid on exit and prevent new additions / removals
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Message ID 20200608170127.20419-6-mcgrof@kernel.org
State New
Headers show
Series
  • block: fix blktrace debugfs use after free
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Commit Message

Luis Chamberlain June 8, 2020, 5:01 p.m. UTC
Be pedantic on removal as well and hold the mutex.
This should prevent uses of addition while we exit.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 drivers/block/loop.c | 4 ++++
 1 file changed, 4 insertions(+)

Patch
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diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index c33bbbfd1bd9..d55e1b52f076 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -2402,6 +2402,8 @@  static void __exit loop_exit(void)
 
 	range = max_loop ? max_loop << part_shift : 1UL << MINORBITS;
 
+	mutex_lock(&loop_ctl_mutex);
+
 	idr_for_each(&loop_index_idr, &loop_exit_cb, NULL);
 	idr_destroy(&loop_index_idr);
 
@@ -2409,6 +2411,8 @@  static void __exit loop_exit(void)
 	unregister_blkdev(LOOP_MAJOR, "loop");
 
 	misc_deregister(&loop_misc);
+
+	mutex_unlock(&loop_ctl_mutex);
 }
 
 module_init(loop_init);