Re: [mm] 4e2c82a409: ltp.overcommit_memory01.fail

[Feng Tang]

Hi,

On Thu, Jul 02, 2020 at 02:32:01PM +0800, kernel test robot wrote:
> Greeting,
> 
> FYI, we noticed the following commit (built with gcc-9):
> 
> commit: 4e2c82a40911c19419349918e675aa202b113b4d ("[PATCH v5 3/3] mm: adjust vm_committed_as_batch according to vm overcommit policy")
> url: https://github.com/0day-ci/linux/commits/Feng-Tang/make-vm_committed_as_batch-aware-of-vm-overcommit-policy/20200621-153906
> 
> 
> in testcase: ltp
> with following parameters:
> 
> 	disk: 1HDD
> 	test: mm-01
> 
> test-description: The LTP testsuite contains a collection of tools for testing the Linux kernel and related features.
> test-url: http://linux-test-project.github.io/
> 
> 
> on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G
> 
> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):
> 
> 
> 
> 
> If you fix the issue, kindly add following tag
> Reported-by: kernel test robot <rong.a.chen@xxxxxxxxx>
> 
> 
> 
> <<<test_start>>>
> tag=overcommit_memory01 stime=1593425044
> cmdline="overcommit_memory"
> contacts=""
> analysis=exit
> <<<test_output>>>
> tst_test.c:1247: INFO: Timeout per run is 0h 05m 00s
> overcommit_memory.c:116: INFO: MemTotal is 16394252 kB
> overcommit_memory.c:118: INFO: SwapTotal is 268435452 kB
> overcommit_memory.c:122: INFO: CommitLimit is 276632576 kB
> mem.c:817: INFO: set overcommit_ratio to 50
> mem.c:817: INFO: set overcommit_memory to 2
> overcommit_memory.c:187: INFO: malloc 551061440 kB failed
> overcommit_memory.c:208: PASS: alloc failed as expected
> overcommit_memory.c:183: INFO: malloc 276632576 kB successfully
> overcommit_memory.c:210: FAIL: alloc passed, expected to fail

Thanks for the report!

I took a rough look, and it all happens after changing the
overcommit policy from a looser one to OVERCOMMIT_NEVER. I suspect 
it is due to the same cause as the previous warning message reported
by Qian Cai https://lore.kernel.org/lkml/20200526181459.GD991@xxxxxx/ 

Will further check it.

Thanks,
Feng

> overcommit_memory.c:183: INFO: malloc 137765294 kB successfully
> overcommit_memory.c:202: PASS: alloc passed as expected
> mem.c:817: INFO: set overcommit_memory to 0
> overcommit_memory.c:183: INFO: malloc 140770308 kB successfully
> overcommit_memory.c:202: PASS: alloc passed as expected
> overcommit_memory.c:187: INFO: malloc 569659408 kB failed
> overcommit_memory.c:208: PASS: alloc failed as expected
> mem.c:817: INFO: set overcommit_memory to 1
> overcommit_memory.c:183: INFO: malloc 142414852 kB successfully
> overcommit_memory.c:202: PASS: alloc passed as expected
> overcommit_memory.c:183: INFO: malloc 284829704 kB successfully
> overcommit_memory.c:202: PASS: alloc passed as expected
> overcommit_memory.c:183: INFO: malloc 569659408 kB successfully
> overcommit_memory.c:202: PASS: alloc passed as expected
> mem.c:817: INFO: set overcommit_memory to 0
> mem.c:817: INFO: set overcommit_ratio to 50
> 
> Summary:
> passed   7
> failed   1
> skipped  0
> warnings 0
> <<<execution_status>>>
> initiation_status="ok"
> duration=0 termination_type=exited termination_id=1 corefile=no
> cutime=0 cstime=1
> <<<test_end>>>
> <<<test_start>>>
> tag=overcommit_memory02 stime=1593425044
> cmdline="overcommit_memory -R 0"
> contacts=""
> analysis=exit
> <<<test_output>>>
> tst_test.c:1247: INFO: Timeout per run is 0h 05m 00s
> overcommit_memory.c:116: INFO: MemTotal is 16394252 kB
> overcommit_memory.c:118: INFO: SwapTotal is 268435452 kB
> overcommit_memory.c:122: INFO: CommitLimit is 276632576 kB
> mem.c:817: INFO: set overcommit_ratio to 0
> mem.c:817: INFO: set overcommit_memory to 2
> overcommit_memory.c:187: INFO: malloc 534667184 kB failed
> overcommit_memory.c:208: PASS: alloc failed as expected
> overcommit_memory.c:183: INFO: malloc 268435452 kB successfully
> overcommit_memory.c:210: FAIL: alloc passed, expected to fail
> overcommit_memory.c:183: INFO: malloc 133666730 kB successfully
> overcommit_memory.c:202: PASS: alloc passed as expected
> mem.c:817: INFO: set overcommit_memory to 0
> overcommit_memory.c:183: INFO: malloc 140770304 kB successfully
> overcommit_memory.c:202: PASS: alloc passed as expected
> overcommit_memory.c:187: INFO: malloc 569659408 kB failed
> overcommit_memory.c:208: PASS: alloc failed as expected
> mem.c:817: INFO: set overcommit_memory to 1
> overcommit_memory.c:183: INFO: malloc 142414852 kB successfully
> overcommit_memory.c:202: PASS: alloc passed as expected
> overcommit_memory.c:183: INFO: malloc 284829704 kB successfully
> overcommit_memory.c:202: PASS: alloc passed as expected
> overcommit_memory.c:183: INFO: malloc 569659408 kB successfully
> overcommit_memory.c:202: PASS: alloc passed as expected
> mem.c:817: INFO: set overcommit_memory to 0
> mem.c:817: INFO: set overcommit_ratio to 50
>