Re: bfq - suspected memory leaks

Il giorno 15 set 2021, alle ore 14:56, Jens Axboe [off-list ref] ha scritto:

On 9/8/21 10:07 PM, Guoqing Jiang wrote:

quoted

Hi,

With latest kernel (commit 4ac6d90867a4 "Merge tag 'docs-5.15' of 
git://git.lwn.net/linux"),
I got lots of kmemleak reports during compile kernel source code.

# dmesg |grep kmemleak
[18234.655491] kmemleak: 1 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[18890.247552] kmemleak: 2 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[19745.602271] kmemleak: 2 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[20390.965851] kmemleak: 4 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[21150.173950] kmemleak: 4 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[21929.951448] kmemleak: 15 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[23589.726859] kmemleak: 2 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[24416.441263] kmemleak: 1 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[30400.835853] kmemleak: 10 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[68673.737862] kmemleak: 2 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[72770.498898] kmemleak: 1 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)
[77046.434369] kmemleak: 7 new suspected memory leaks (see 
/sys/kernel/debug/kmemleak)

All of them  have similar trace as follows.

  comm "sh", pid 27054, jiffies 4302241171 (age 47562.964s)
  hex dump (first 32 bytes):
    01 00 00 00 00 00 00 00 00 b0 20 02 80 88 ff ff  .......... .....
    04 00 02 00 04 00 02 00 00 00 00 00 00 00 00 00 ................
  backtrace:
    [<000000004fa2550b>] bfq_get_queue+0x2a8/0xfd0
    [<00000000b1757a70>] bfq_get_bfqq_handle_split+0xa4/0x240
    [<00000000ac263274>] bfq_init_rq+0x1f7/0x1d10
    [<00000000110283e1>] bfq_insert_requests+0xf7/0x5f0
    [<000000002ed06e79>] blk_mq_sched_insert_requests+0xfe/0x350
    [<000000000ebf38ac>] blk_mq_flush_plug_list+0x256/0x3e0
    [<00000000bc647b2b>] blk_flush_plug_list+0x1ff/0x240
    [<000000004e7e49f8>] blk_finish_plug+0x3c/0x60
    [<000000008802f1e4>] read_pages+0x28f/0x580
    [<000000009986d1f4>] page_cache_ra_unbounded+0x266/0x3a0
    [<00000000492c494f>] filemap_fault+0x8a8/0xfe0
    [<000000009cbd8d38>] __do_fault+0x70/0x150
    [<000000002740a35f>] do_fault+0x112/0x670
    [<00000000a74facab>] __handle_mm_fault+0x57e/0xcc0
    [<0000000024009667>] handle_mm_fault+0xd6/0x330
    [<00000000fb1e0780>] do_user_addr_fault+0x2a9/0x8b0
unreferenced object 0xffff888021e5dd90 (size 560):

Paolo, are you on top of this one?

Thanks Guoqing for reporting this.  I'm overloaded at the moment,
please give me a little time and I'll have a look.

Paolo

-- 
Jens Axboe