On 11/22/10 12:02 AM, zeng.zhaoming@xxxxxxxxxxxxx wrote:
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> ---
Hmm. Maybe it's better to change SLAB and SLOB to do kstrdup() internally so we can drop it from ext4 code. Matt, are you OK with that?
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