[PATCH v2] btrfs: zoned: free zone_cache when freeing zone_info

[PATCH v2] btrfs: zoned: free zone_cache when freeing zone_info

[Johannes Thumshirn]

Kmemleak was reporting the following memory leak on fstests btrfs/224 on my
zoned test setup:

 unreferenced object 0xffffc900001a9000 (size 4096):
   comm "mount", pid 1781, jiffies 4295339102 (age 5.740s)
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 00 00 08 00 00 00 00 00  ................
     00 00 08 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
   backtrace:
     [<00000000b0ef6261>] __vmalloc_node_range+0x240/0x3d0
     [<00000000aa06ac88>] vzalloc+0x3c/0x50
     [<000000001824c35c>] btrfs_get_dev_zone_info+0x426/0x7e0 [btrfs]
     [<0000000004ba8d9d>] btrfs_get_dev_zone_info_all_devices+0x52/0x80 [btrfs]
     [<0000000054bc27eb>] open_ctree+0x1022/0x1709 [btrfs]
     [<0000000074fe7dc0>] btrfs_mount_root.cold+0x13/0xe5 [btrfs]
     [<00000000a54ca18b>] legacy_get_tree+0x22/0x40
     [<00000000ce480896>] vfs_get_tree+0x1b/0x80
     [<000000006423c6bd>] vfs_kern_mount.part.0+0x6c/0xa0
     [<000000003cf6fc28>] btrfs_mount+0x10d/0x380 [btrfs]
     [<00000000a54ca18b>] legacy_get_tree+0x22/0x40
     [<00000000ce480896>] vfs_get_tree+0x1b/0x80
     [<00000000995da674>] path_mount+0x6b6/0xa10
     [<00000000a5b4b6ec>] __x64_sys_mount+0xde/0x110
     [<00000000fe985c23>] do_syscall_64+0x43/0x90
     [<00000000c6071ff4>] entry_SYSCALL_64_after_hwframe+0x44/0xae

The allocated object in question is the zone_cache.

Free it when freeing a btrfs_device's zone_info.

Also as the cleanup code in btrfs_get_dev_zone_info() utilizes the same
pattern btrfs_destroy_dev_zone_info() is using directly call
btrfs_destroy_dev_zone_info() instead of open-coding it.

Fixes: dea0e0d65459 ("btrfs: cache reported zone during mount")
Cc: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

---
Changes to v1:
- call btrfs_destroy_dev_zone_info in btrfs_get_dev_zone_info's cleanup
  path
---
 fs/btrfs/zoned.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 9cdef5e8f6b7..6a00f49a397c 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -592,12 +592,7 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache)
 out:
 	kfree(zones);
 out_free_zone_info:
-	bitmap_free(zone_info->active_zones);
-	bitmap_free(zone_info->empty_zones);
-	bitmap_free(zone_info->seq_zones);
-	vfree(zone_info->zone_cache);
-	kfree(zone_info);
-	device->zone_info = NULL;
+	btrfs_destroy_dev_zone_info(device);
 
 	return ret;
 }
@@ -612,6 +607,7 @@ void btrfs_destroy_dev_zone_info(struct btrfs_device *device)
 	bitmap_free(zone_info->active_zones);
 	bitmap_free(zone_info->seq_zones);
 	bitmap_free(zone_info->empty_zones);
+	vfree(zone_info->zone_cache);
 	kfree(zone_info);
 	device->zone_info = NULL;
 }
-- 
2.31.1

Re: [PATCH v2] btrfs: zoned: free zone_cache when freeing zone_info

[David Sterba]

On Tue, Dec 07, 2021 at 05:58:13AM -0800, Johannes Thumshirn wrote:
> Kmemleak was reporting the following memory leak on fstests btrfs/224 on my
> zoned test setup:
> 
>  unreferenced object 0xffffc900001a9000 (size 4096):
>    comm "mount", pid 1781, jiffies 4295339102 (age 5.740s)
>    hex dump (first 32 bytes):
>      00 00 00 00 00 00 00 00 00 00 08 00 00 00 00 00  ................
>      00 00 08 00 00 00 00 00 01 00 00 00 00 00 00 00  ................
>    backtrace:
>      [<00000000b0ef6261>] __vmalloc_node_range+0x240/0x3d0
>      [<00000000aa06ac88>] vzalloc+0x3c/0x50
>      [<000000001824c35c>] btrfs_get_dev_zone_info+0x426/0x7e0 [btrfs]
>      [<0000000004ba8d9d>] btrfs_get_dev_zone_info_all_devices+0x52/0x80 [btrfs]
>      [<0000000054bc27eb>] open_ctree+0x1022/0x1709 [btrfs]
>      [<0000000074fe7dc0>] btrfs_mount_root.cold+0x13/0xe5 [btrfs]
>      [<00000000a54ca18b>] legacy_get_tree+0x22/0x40
>      [<00000000ce480896>] vfs_get_tree+0x1b/0x80
>      [<000000006423c6bd>] vfs_kern_mount.part.0+0x6c/0xa0
>      [<000000003cf6fc28>] btrfs_mount+0x10d/0x380 [btrfs]
>      [<00000000a54ca18b>] legacy_get_tree+0x22/0x40
>      [<00000000ce480896>] vfs_get_tree+0x1b/0x80
>      [<00000000995da674>] path_mount+0x6b6/0xa10
>      [<00000000a5b4b6ec>] __x64_sys_mount+0xde/0x110
>      [<00000000fe985c23>] do_syscall_64+0x43/0x90
>      [<00000000c6071ff4>] entry_SYSCALL_64_after_hwframe+0x44/0xae
> 
> The allocated object in question is the zone_cache.
> 
> Free it when freeing a btrfs_device's zone_info.
> 
> Also as the cleanup code in btrfs_get_dev_zone_info() utilizes the same
> pattern btrfs_destroy_dev_zone_info() is using directly call
> btrfs_destroy_dev_zone_info() instead of open-coding it.
> 
> Fixes: dea0e0d65459 ("btrfs: cache reported zone during mount")
> Cc: Naohiro Aota <naohiro.aota@wdc.com>
> Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>

Added to misc-next, thanks.