6.12-stable review patch. If anyone has any objections, please let me know.
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From: Damien Le Moal dlemoal@kernel.org
commit c2b8d20628ca789640f64074a642f9440eefc623 upstream.
For zoned block devices that do not need zone write plugs (e.g. most device mapper devices that support zones), the disk hash table of zone write plugs is NULL. For such devices, blk_zone_reset_all_bio_endio() should not attempt to scan this has table as that causes a NULL pointer dereference.
Fix this by checking that the disk does have zone write plugs using the atomic counter. This is equivalent to checking for a non-NULL hash table but has the advantage to also speed up the execution of blk_zone_reset_all_bio_endio() for devices that do use zone write plugs but do not have any plug in the hash table (e.g. a disk with only full zones).
Fixes: efae226c2ef1 ("block: handle zone management operations completions") Reported-by: Shin'ichiro Kawasaki shinichiro.kawasaki@wdc.com Signed-off-by: Damien Le Moal dlemoal@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- block/blk-zoned.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-)
--- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -746,17 +746,20 @@ static void blk_zone_reset_all_bio_endio unsigned long flags; unsigned int i;
- /* Update the condition of all zone write plugs. */ - rcu_read_lock(); - for (i = 0; i < disk_zone_wplugs_hash_size(disk); i++) { - hlist_for_each_entry_rcu(zwplug, &disk->zone_wplugs_hash[i], - node) { - spin_lock_irqsave(&zwplug->lock, flags); - disk_zone_wplug_set_wp_offset(disk, zwplug, 0); - spin_unlock_irqrestore(&zwplug->lock, flags); + if (atomic_read(&disk->nr_zone_wplugs)) { + /* Update the condition of all zone write plugs. */ + rcu_read_lock(); + for (i = 0; i < disk_zone_wplugs_hash_size(disk); i++) { + hlist_for_each_entry_rcu(zwplug, + &disk->zone_wplugs_hash[i], + node) { + spin_lock_irqsave(&zwplug->lock, flags); + disk_zone_wplug_set_wp_offset(disk, zwplug, 0); + spin_unlock_irqrestore(&zwplug->lock, flags); + } } + rcu_read_unlock(); } - rcu_read_unlock(); }
static void blk_zone_finish_bio_endio(struct bio *bio)