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v4.4-rc3 ext4 memory leak

DISCUSSION Bart Van Assche 2 participants 3 messages Dec 3, 2015 – Dec 4, 2015

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Bart Van Assche

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#0 lore raw

Hello,

Running xfstests on top of an ext4 filesystem causes kmemleak to report the following memory leak multiple times:

unreferenced object 0xffff880408709730 (size 96):
comm "fsstress", pid 35588, jiffies 4295006079 (age 11865.680s) hex dump (first 32 bytes):

    00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8151056a>] kmemleak_alloc+0x7a/0xc0
    [<ffffffff81165e6e>] __kmalloc+0xde/0x140
    [<ffffffffa022472e>] ext4_find_extent+0x26e/0x310 [ext4]
    [<ffffffffa0227f15>] ext4_insert_range+0x255/0x3c0 [ext4]
    [<ffffffffa022aca1>] ext4_fallocate+0x1f1/0x210 [ext4]
    [<ffffffff81175fb6>] vfs_fallocate+0x156/0x1e0
    [<ffffffff8117608e>] SyS_fallocate+0x4e/0x80
    [<ffffffff8151b617>] entry_SYSCALL_64_fastpath+0x12/0x6f
    [<ffffffffffffffff>] 0xffffffffffffffff

Bart.

#1 lore raw
Quoted 8 lines · Bart Van Assche

Hello,

Running xfstests on top of an ext4 filesystem causes kmemleak to report the following memory leak multiple times:

unreferenced object 0xffff880408709730 (size 96):
comm "fsstress", pid 35588, jiffies 4295006079 (age 11865.680s) hex dump (first 32 bytes):

Quoted 12 lines
    00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8151056a>] kmemleak_alloc+0x7a/0xc0
    [<ffffffff81165e6e>] __kmalloc+0xde/0x140
    [<ffffffffa022472e>] ext4_find_extent+0x26e/0x310 [ext4]
    [<ffffffffa0227f15>] ext4_insert_range+0x255/0x3c0 [ext4]
    [<ffffffffa022aca1>] ext4_fallocate+0x1f1/0x210 [ext4]
    [<ffffffff81175fb6>] vfs_fallocate+0x156/0x1e0
    [<ffffffff8117608e>] SyS_fallocate+0x4e/0x80
    [<ffffffff8151b617>] entry_SYSCALL_64_fastpath+0x12/0x6f
    [<ffffffffffffffff>] 0xffffffffffffffff

Is this something new? i..e, was this reproducible on v4.3?

And can you isolate this to a specific test in xfstests?

Thanks,

- Ted

author
#2 lore raw
Quoted 22 lines · Theodore Ts'o
Quoted 6 lines · Bart Van Assche

Hello,

Running xfstests on top of an ext4 filesystem causes kmemleak to report the following memory leak multiple times:

unreferenced object 0xffff880408709730 (size 96):

Quoted 14 lines
   comm "fsstress", pid 35588, jiffies 4295006079 (age 11865.680s)
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00  ................
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
   backtrace:
     [<ffffffff8151056a>] kmemleak_alloc+0x7a/0xc0
     [<ffffffff81165e6e>] __kmalloc+0xde/0x140
     [<ffffffffa022472e>] ext4_find_extent+0x26e/0x310 [ext4]
     [<ffffffffa0227f15>] ext4_insert_range+0x255/0x3c0 [ext4]
     [<ffffffffa022aca1>] ext4_fallocate+0x1f1/0x210 [ext4]
     [<ffffffff81175fb6>] vfs_fallocate+0x156/0x1e0
     [<ffffffff8117608e>] SyS_fallocate+0x4e/0x80
     [<ffffffff8151b617>] entry_SYSCALL_64_fastpath+0x12/0x6f
     [<ffffffffffffffff>] 0xffffffffffffffff
Quoted 3 lines

Is this something new? i..e, was this reproducible on v4.3?

And can you isolate this to a specific test in xfstests?

Hello Ted,

So far I only ran xfstests against the 4.4-rc3 kernel so I do not know whether this also occurred with previous kernel versions.

kmemleak scans periodically for memory leaks. kmemleak started reporting these leaks after test generic/037 had started. So I think one of the first 37 tests triggered this leak.

Bart.