[igt-dev] [PATCH i-g-t] tests/xe/debugfs: fix double-free in test_base

[Matthew Auld]

On Wed, 15 Mar 2023 at 15:02, Matthew Auld <matthew.auld at intel.com> wrote:
>
> Looks to incorrectly free the xe_dev->config, even though there is still
> a cached entry pointing to it. The test fixture will also call
> xe_device_put() at the end, freeing the same pointer (might now point to
> valid memory), which hopefully explains why we see strange looking
> crashes in CI:
>
> Starting subtest: base
> Subtest base: SUCCESS (0.005s)
> Received signal SIGABRT.
> Stack trace:
>  #0 [fatal_sig_handler+0x10f]
>  #1 [killpg+0x40]
>  #2 [gsignal+0xcb]
>  #3 [abort+0x12b]
>  #4 [__fsetlocking+0x42e]
>  #5 [pthread_attr_setschedparam+0x54c]
>  #6 [pthread_attr_setschedparam+0xd28]
>  #7 [pthread_attr_setschedparam+0x2ed3]
>  #8 [__libc_malloc+0x74]
>  #9 [_IO_file_doallocate+0x94]
>  #10 [_IO_doallocbuf+0x50]
>  #11 [_IO_file_overflow+0x1b0]
>  #12 [_IO_file_xsputn+0xe5]
>  #13 [psiginfo+0x13512]
>  #14 [igt_kmsg+0xc9]
>  #15 [igt_exit+0xd3]
>  #16 [main+0x44]
>  #17 [__libc_start_main+0xf3]
>  #18 [_start+0x2e]
>
> Keep the xe_device stuff in test_base, since that looks be the only user
> here.
>
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> Cc: Zbigniew Kempczynski <zbigniew.kempczynski at intel.com>
> Cc: Mauro Carvalho Chehab <mchehab at kernel.org>

Ping? Any takers for this one?

> ---
>  tests/xe/xe_debugfs.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/tests/xe/xe_debugfs.c b/tests/xe/xe_debugfs.c
> index 38c8becc..ddb01568 100644
> --- a/tests/xe/xe_debugfs.c
> +++ b/tests/xe/xe_debugfs.c
> @@ -146,7 +146,7 @@ test_base(int fd)
>
>         validate_entries(fd, "", expected_files, ARRAY_SIZE(expected_files));
>
> -       free(config);
> +       xe_device_put(fd);
>  }
>
>  /**
> @@ -250,7 +250,6 @@ igt_main_args("", long_options, help_str, opt_handler, NULL)
>
>         igt_fixture {
>                 fd = drm_open_driver(DRIVER_XE);
> -               xe_device_get(fd);
>                 __igt_debugfs_dump(fd, "info", IGT_LOG_INFO);
>         }
>
> @@ -272,7 +271,6 @@ igt_main_args("", long_options, help_str, opt_handler, NULL)
>         }
>
>         igt_fixture {
> -               xe_device_put(fd);
>                 close(fd);
>         }
>  }
> --
> 2.39.2
>