From: Zeng Zhaoming<zengzm.kernel@xxxxxxxxx>
please check the discuss with allocator guys.
http://marc.info/?l=linux-kernel&m=129004890020256&w=2
Get a memory leak about ext4:
comm "mount", pid 1159, jiffies 4294904647 (age 6077.804s)
hex dump (first 32 bytes):
65 78 74 34 5f 67 72 6f 75 70 69 6e 66 6f 5f 31 ext4_groupinfo_1
30 00 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 0.kkkkkkkkkkkkk.
backtrace:
[<c068ade3>] kmemleak_alloc+0x93/0xd0
[<c024e54c>] __kmalloc_track_caller+0x30c/0x380
[<c02269d3>] kstrdup+0x33/0x60
[<c0318a70>] ext4_mb_init+0x4e0/0x550
[<c0304e0e>] ext4_fill_super+0x1e6e/0x2f60
[<c0261140>] mount_bdev+0x1c0/0x1f0
[<c02fc00f>] ext4_mount+0x1f/0x30
[<c02603d8>] vfs_kern_mount+0x78/0x250
[<c026060e>] do_kern_mount+0x3e/0x100
[<c027b4c2>] do_mount+0x2e2/0x780
[<c027ba04>] sys_mount+0xa4/0xd0
[<c010429f>] sysenter_do_call+0x12/0x38
[<ffffffff>] 0xffffffff
ext4 allocate memory for cache name by:
namep = kstrdup(name, GFP_KERNEL);
and reclaim it by:
name = kmem_cache_name(cache);
kfree(name)
This is ok if allocator only reference to the cache name memory, and return
the name memory pass to kmem_cache_create() by kmem_cache_name();
But not true in slub, when using slub, memory leak and double free error appears.
In this patch, we track the cache name memory in ext4, rather than allocator.
Signed-off-by: Zeng Zhaoming<zengzm.kernel@xxxxxxxxx>
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