6.15-stable review patch. If anyone has any objections, please let me know.
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From: Benjamin Marzinski bmarzins@redhat.com
[ Upstream commit 37f53a2c60d03743e0eacf7a0c01c279776fef4e ]
If dm_get_live_table() returned NULL, dm_put_live_table() was never called. Also, it is possible that md->zone_revalidate_map will change while calling this function. Only read it once, so that we are always using the same value. Otherwise we might miss a call to dm_put_live_table().
Finally, while md->zone_revalidate_map is set and a process is calling blk_revalidate_disk_zones() to set up the zone append emulation resources, it is possible that another process, perhaps triggered by blkdev_report_zones_ioctl(), will call dm_blk_report_zones(). If blk_revalidate_disk_zones() fails, these resources can be freed while the other process is still using them, causing a use-after-free error.
blk_revalidate_disk_zones() will only ever be called when initially setting up the zone append emulation resources, such as when setting up a zoned dm-crypt table for the first time. Further table swaps will not set md->zone_revalidate_map or call blk_revalidate_disk_zones(). However it must be called using the new table (referenced by md->zone_revalidate_map) and the new queue limits while the DM device is suspended. dm_blk_report_zones() needs some way to distinguish between a call from blk_revalidate_disk_zones(), which must be allowed to use md->zone_revalidate_map to access this not yet activated table, and all other calls to dm_blk_report_zones(), which should not be allowed while the device is suspended and cannot use md->zone_revalidate_map, since the zone resources might be freed by the process currently calling blk_revalidate_disk_zones().
Solve this by tracking the process that sets md->zone_revalidate_map in dm_revalidate_zones() and only allowing that process to make use of it in dm_blk_report_zones().
Fixes: f211268ed1f9b ("dm: Use the block layer zone append emulation") Reviewed-by: Damien Le Moal dlemoal@kernel.org Tested-by: Damien Le Moal dlemoal@kernel.org Signed-off-by: Benjamin Marzinski bmarzins@redhat.com Signed-off-by: Mikulas Patocka mpatocka@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/md/dm-core.h | 1 + drivers/md/dm-zone.c | 25 +++++++++++++++++-------- 2 files changed, 18 insertions(+), 8 deletions(-)
diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h index 3637761f35853..f3a3f2ef63226 100644 --- a/drivers/md/dm-core.h +++ b/drivers/md/dm-core.h @@ -141,6 +141,7 @@ struct mapped_device { #ifdef CONFIG_BLK_DEV_ZONED unsigned int nr_zones; void *zone_revalidate_map; + struct task_struct *revalidate_map_task; #endif
#ifdef CONFIG_IMA diff --git a/drivers/md/dm-zone.c b/drivers/md/dm-zone.c index 681058feb63b5..ff9a1a94eea96 100644 --- a/drivers/md/dm-zone.c +++ b/drivers/md/dm-zone.c @@ -56,24 +56,31 @@ int dm_blk_report_zones(struct gendisk *disk, sector_t sector, { struct mapped_device *md = disk->private_data; struct dm_table *map; - int srcu_idx, ret; + struct dm_table *zone_revalidate_map = md->zone_revalidate_map; + int srcu_idx, ret = -EIO; + bool put_table = false;
- if (!md->zone_revalidate_map) { - /* Regular user context */ + if (!zone_revalidate_map || md->revalidate_map_task != current) { + /* + * Regular user context or + * Zone revalidation during __bind() is in progress, but this + * call is from a different process + */ if (dm_suspended_md(md)) return -EAGAIN;
map = dm_get_live_table(md, &srcu_idx); - if (!map) - return -EIO; + put_table = true; } else { /* Zone revalidation during __bind() */ - map = md->zone_revalidate_map; + map = zone_revalidate_map; }
- ret = dm_blk_do_report_zones(md, map, sector, nr_zones, cb, data); + if (map) + ret = dm_blk_do_report_zones(md, map, sector, nr_zones, cb, + data);
- if (!md->zone_revalidate_map) + if (put_table) dm_put_live_table(md, srcu_idx);
return ret; @@ -175,7 +182,9 @@ int dm_revalidate_zones(struct dm_table *t, struct request_queue *q) * our table for dm_blk_report_zones() to use directly. */ md->zone_revalidate_map = t; + md->revalidate_map_task = current; ret = blk_revalidate_disk_zones(disk); + md->revalidate_map_task = NULL; md->zone_revalidate_map = NULL;
if (ret) {