e923b0537d
In rseq_test, there are two threads, which are vCPU thread and migration
worker separately. Unfortunately, the test has the wrong PID passed to
sched_setaffinity() in the migration worker. It forces migration on the
migration worker because zeroed PID represents the calling thread, which
is the migration worker itself. It means the vCPU thread is never enforced
to migration and it can migrate at any time, which eventually leads to
failure as the following logs show.
host# uname -r
5.19.0-rc6-gavin+
host# # cat /proc/cpuinfo | grep processor | tail -n 1
processor : 223
host# pwd
/home/gavin/sandbox/linux.main/tools/testing/selftests/kvm
host# for i in `seq 1 100`; do \
echo "--------> $i"; ./rseq_test; done
--------> 1
--------> 2
--------> 3
--------> 4
--------> 5
--------> 6
==== Test Assertion Failure ====
rseq_test.c:265: rseq_cpu == cpu
pid=3925 tid=3925 errno=4 - Interrupted system call
1 0x0000000000401963: main at rseq_test.c:265 (discriminator 2)
2 0x0000ffffb044affb: ?? ??:0
3 0x0000ffffb044b0c7: ?? ??:0
4 0x0000000000401a6f: _start at ??:?
rseq CPU = 4, sched CPU = 27
Fix the issue by passing correct parameter, TID of the vCPU thread, to
sched_setaffinity() in the migration worker.
Fixes: 61e52f1630f5 ("KVM: selftests: Add a test for KVM_RUN+rseq to detect task migration bugs")
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Message-Id: <20220719020830.3479482-1-gshan@redhat.com>
Reviewed-by: Andrew Jones <andrew.jones@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.