From: Mirsad Todorovac <mirsad.todorovac@alu.unizg.hr>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: iommu@lists.linux.dev, Kevin Tian <kevin.tian@intel.com>,
Shuah Khan <shuah@kernel.org>,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [BUG] seltests/iommu: runaway ./iommufd consuming 99% CPU after a failed assert()
Date: Sat, 23 Mar 2024 21:13:01 +0100 [thread overview]
Message-ID: <a692d5d7-11d5-4c1b-9abc-208d2194ccde@alu.unizg.hr> (raw)
In-Reply-To: <20240319135852.GA393211@nvidia.com>
On 3/19/24 14:58, Jason Gunthorpe wrote:
> On Tue, Mar 12, 2024 at 07:35:40AM +0100, Mirsad Todorovac wrote:
>> Hi,
>>
>> (This is verified on the second test box.)
>>
>> In the most recent 6.8.0 release of torvalds tree kernel with selftest configs on,
>> process ./iommufd appears to consume 99% of a CPU core for quote a while in an
>> endless loop:
>
> There is a "bug" in the ksefltest framework where if you call a
> kselftest assertion from the setup/teardown it infinite loops
>
> The fix I know is to replace kselftest assertions with normal assert()
>
> But I don't see an obvious thing here saying you are hitting that..
>
> Jason
Hi,
I'm not that deep into kselftest for that intervention.
Yet, with the v6.8-11743-ga4145ce1e7bc build, the problem with ./iommufd did not stuck.
Instead I got these 10 failed tests:
# # RUN iommufd_dirty_tracking.domain_dirty128M_huge.enforce_dirty ...
# iommufd: iommufd.c:1749: iommufd_dirty_tracking_setup: Assertion `vrc == self->buffer' failed.
# # enforce_dirty: Test terminated by assertion
# # FAIL iommufd_dirty_tracking.domain_dirty128M_huge.enforce_dirty
# not ok 156 iommufd_dirty_tracking.domain_dirty128M_huge.enforce_dirty
# # RUN iommufd_dirty_tracking.domain_dirty128M_huge.set_dirty_tracking ...
# iommufd: iommufd.c:1749: iommufd_dirty_tracking_setup: Assertion `vrc == self->buffer' failed.
# # set_dirty_tracking: Test terminated by assertion
# # FAIL iommufd_dirty_tracking.domain_dirty128M_huge.set_dirty_tracking
# not ok 157 iommufd_dirty_tracking.domain_dirty128M_huge.set_dirty_tracking
# # RUN iommufd_dirty_tracking.domain_dirty128M_huge.device_dirty_capability ...
# iommufd: iommufd.c:1749: iommufd_dirty_tracking_setup: Assertion `vrc == self->buffer' failed.
# # device_dirty_capability: Test terminated by assertion
# # FAIL iommufd_dirty_tracking.domain_dirty128M_huge.device_dirty_capability
# not ok 158 iommufd_dirty_tracking.domain_dirty128M_huge.device_dirty_capability
# # RUN iommufd_dirty_tracking.domain_dirty128M_huge.get_dirty_bitmap ...
# iommufd: iommufd.c:1749: iommufd_dirty_tracking_setup: Assertion `vrc == self->buffer' failed.
# # get_dirty_bitmap: Test terminated by assertion
# # FAIL iommufd_dirty_tracking.domain_dirty128M_huge.get_dirty_bitmap
# not ok 159 iommufd_dirty_tracking.domain_dirty128M_huge.get_dirty_bitmap
# # RUN iommufd_dirty_tracking.domain_dirty128M_huge.get_dirty_bitmap_no_clear ...
# iommufd: iommufd.c:1749: iommufd_dirty_tracking_setup: Assertion `vrc == self->buffer' failed.
# # get_dirty_bitmap_no_clear: Test terminated by assertion
# # FAIL iommufd_dirty_tracking.domain_dirty128M_huge.get_dirty_bitmap_no_clear
# not ok 160 iommufd_dirty_tracking.domain_dirty128M_huge.get_dirty_bitmap_no_clear
.
.
.
# # RUN iommufd_dirty_tracking.domain_dirty256M_huge.enforce_dirty ...
# iommufd: iommufd.c:1749: iommufd_dirty_tracking_setup: Assertion `vrc == self->buffer' failed.
# # enforce_dirty: Test terminated by assertion
# # FAIL iommufd_dirty_tracking.domain_dirty256M_huge.enforce_dirty
# not ok 166 iommufd_dirty_tracking.domain_dirty256M_huge.enforce_dirty
# # RUN iommufd_dirty_tracking.domain_dirty256M_huge.set_dirty_tracking ...
# iommufd: iommufd.c:1749: iommufd_dirty_tracking_setup: Assertion `vrc == self->buffer' failed.
# # set_dirty_tracking: Test terminated by assertion
# # FAIL iommufd_dirty_tracking.domain_dirty256M_huge.set_dirty_tracking
# not ok 167 iommufd_dirty_tracking.domain_dirty256M_huge.set_dirty_tracking
# # RUN iommufd_dirty_tracking.domain_dirty256M_huge.device_dirty_capability ...
# iommufd: iommufd.c:1749: iommufd_dirty_tracking_setup: Assertion `vrc == self->buffer' failed.
# # device_dirty_capability: Test terminated by assertion
# # FAIL iommufd_dirty_tracking.domain_dirty256M_huge.device_dirty_capability
# not ok 168 iommufd_dirty_tracking.domain_dirty256M_huge.device_dirty_capability
# # RUN iommufd_dirty_tracking.domain_dirty256M_huge.get_dirty_bitmap ...
# iommufd: iommufd.c:1749: iommufd_dirty_tracking_setup: Assertion `vrc == self->buffer' failed.
# # get_dirty_bitmap: Test terminated by assertion
# # FAIL iommufd_dirty_tracking.domain_dirty256M_huge.get_dirty_bitmap
# not ok 169 iommufd_dirty_tracking.domain_dirty256M_huge.get_dirty_bitmap
# # RUN iommufd_dirty_tracking.domain_dirty256M_huge.get_dirty_bitmap_no_clear ...
# iommufd: iommufd.c:1749: iommufd_dirty_tracking_setup: Assertion `vrc == self->buffer' failed.
# # get_dirty_bitmap_no_clear: Test terminated by assertion
# # FAIL iommufd_dirty_tracking.domain_dirty256M_huge.get_dirty_bitmap_no_clear
# not ok 170 iommufd_dirty_tracking.domain_dirty256M_huge.get_dirty_bitmap_no_clear
.
.
.
# # FAILED: 170 / 180 tests passed.
# # Totals: pass:170 fail:10 xfail:0 xpass:0 skip:0 error:0
not ok 1 selftests: iommu: iommufd # exit=1
It seems like the same assertion failed in all 10 failed tests?
However, I am not smart enough to figure out why ...
Apparently, from the source, mmap() fails to allocate pages on the desired address:
1746 assert((uintptr_t)self->buffer % HUGEPAGE_SIZE == 0);
1747 vrc = mmap(self->buffer, variant->buffer_size, PROT_READ | PROT_WRITE,
1748 mmap_flags, -1, 0);
→ 1749 assert(vrc == self->buffer);
1750
But I am not that deep into the source to figure our what was intended and what went
wrong :-/
Best regards,
Mirsad Todorovac
next prev parent reply other threads:[~2024-03-23 20:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-12 6:35 [BUG] seltests/iommu: runaway ./iommufd consuming 99% CPU after a failed assert() Mirsad Todorovac
2024-03-19 13:58 ` Jason Gunthorpe
2024-03-23 20:13 ` Mirsad Todorovac [this message]
2024-03-25 12:17 ` Joao Martins
2024-03-25 13:52 ` Jason Gunthorpe
2024-03-27 10:41 ` Joao Martins
2024-03-27 11:40 ` Jason Gunthorpe
2024-03-27 15:04 ` Joao Martins
2024-03-27 16:38 ` Jason Gunthorpe
2024-03-28 0:05 ` Shuah Khan
2024-04-02 11:33 ` Jason Gunthorpe
2024-03-27 20:04 ` Mirsad Todorovac
2024-03-28 13:54 ` Joao Martins
2024-04-04 16:54 ` Shuah Khan
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