Commit 89a459e0 authored Nov 08, 2017 by Zdenek Kabelac Committed by Greg Kroah-Hartman Dec 17, 2017

md: free unused memory after bitmap resize




[ Upstream commit 0868b99c214a3d55486c700de7c3f770b7243e7c ]

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 <zkabelac@redhat.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 2c727856

drivers/md/bitmap.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -2158,6 +2158,7 @@ int bitmap_resize(struct bitmap *bitmap, sector_t blocks,
		for (k = 0; k < page; k++) {
		kfree(new_bp[k].map);
		}
		kfree(new_bp);

		/* restore some fields from old_counts */
		bitmap->counts.bp = old_counts.bp;
		@@ -2208,6 +2209,14 @@ int bitmap_resize(struct bitmap *bitmap, sector_t blocks,
		block += old_blocks;
		}

		if (bitmap->counts.bp != old_counts.bp) {
		unsigned long k;
		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;
		while (block < (chunks << chunkshift)) {