Re: [PATCH 2/2] md: free unused memory after bitmap resize
From: Guoqing Jiang <hidden>
Date: 2017-11-09 03:57:44
On 11/08/2017 08:44 PM, Zdenek Kabelac wrote:
quoted hunk ↗ jump to hunk
When bitmap is resized, the old kalloced chunks just are not released once the resized bitmap starts to use new space. This fixes in particular kmemleak reports like this one: unreferenced object 0xffff8f4311e9c000 (size 4096): comm "lvm", pid 19333, jiffies 4295263268 (age 528.265s) hex dump (first 32 bytes): 02 80 02 80 02 80 02 80 02 80 02 80 02 80 02 80 ................ 02 80 02 80 02 80 02 80 02 80 02 80 02 80 02 80 ................ backtrace: [<ffffffffa69471ca>] kmemleak_alloc+0x4a/0xa0 [<ffffffffa628c10e>] kmem_cache_alloc_trace+0x14e/0x2e0 [<ffffffffa676cfec>] bitmap_checkpage+0x7c/0x110 [<ffffffffa676d0c5>] bitmap_get_counter+0x45/0xd0 [<ffffffffa676d6b3>] bitmap_set_memory_bits+0x43/0xe0 [<ffffffffa676e41c>] bitmap_init_from_disk+0x23c/0x530 [<ffffffffa676f1ae>] bitmap_load+0xbe/0x160 [<ffffffffc04c47d3>] raid_preresume+0x203/0x2f0 [dm_raid] [<ffffffffa677762f>] dm_table_resume_targets+0x4f/0xe0 [<ffffffffa6774b52>] dm_resume+0x122/0x140 [<ffffffffa6779b9f>] dev_suspend+0x18f/0x290 [<ffffffffa677a3a7>] ctl_ioctl+0x287/0x560 [<ffffffffa677a693>] dm_ctl_ioctl+0x13/0x20 [<ffffffffa62d6b46>] do_vfs_ioctl+0xa6/0x750 [<ffffffffa62d7269>] SyS_ioctl+0x79/0x90 [<ffffffffa6956d41>] entry_SYSCALL_64_fastpath+0x1f/0xc2 Signed-off-by: Zdenek Kabelac <redacted> --- drivers/md/bitmap.c | 9 +++++++++ 1 file changed, 9 insertions(+)diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index d2121637b4ab..58ee21027709 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c
The bitmap.c is renamed to md-bitmap.c now.
quoted hunk ↗ jump to hunk
@@ -2152,6 +2152,7 @@ int bitmap_resize(struct bitmap *bitmap, sector_t blocks, for (k = 0; k < page; k++) { kfree(new_bp[k].map); } + kfree(new_bp);
Agreed.
quoted hunk ↗ jump to hunk
/* restore some fields from old_counts */ bitmap->counts.bp = old_counts.bp;@@ -2202,6 +2203,14 @@ int bitmap_resize(struct bitmap *bitmap, sector_t blocks, block += old_blocks; } + if (bitmap->counts.bp != old_counts.bp) { + unsigned long k;
Just nit-picking, maybe you can move belows to
+ for (k = 0; k < old_counts.pages; k++)
+ if (!old_counts.bp[k].hijacked)
+ kfree(old_counts.bp[k].map);
+ kfree(old_counts.bp);
+ }
+
if (!init) {
int i;here and reuse the 'i'. Thanks, Guoqing