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| author | Eric W. Biederman <ebiederm@xmission.com> | 2021-04-30 17:06:01 -0500 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2021-05-18 16:17:03 -0500 |
| commit | add0b32ef9146a8559a60aed54c37692a5f9d34f (patch) | |
| tree | 2fae531f39ba89ce5e1fb6ffc0212f83df8c0c6a /kernel | |
| parent | 42dec9a936e7696bea1f27d3c5a0068cd9aa95fd (diff) | |
| download | linux-stable-add0b32ef9146a8559a60aed54c37692a5f9d34f.tar.gz linux-stable-add0b32ef9146a8559a60aed54c37692a5f9d34f.tar.bz2 linux-stable-add0b32ef9146a8559a60aed54c37692a5f9d34f.zip | |
siginfo: Move si_trapno inside the union inside _si_fault
It turns out that linux uses si_trapno very sparingly, and as such it
can be considered extra information for a very narrow selection of
signals, rather than information that is present with every fault
reported in siginfo.
As such move si_trapno inside the union inside of _si_fault. This
results in no change in placement, and makes it eaiser
to extend _si_fault in the future as this reduces the number of
special cases. In particular with si_trapno included in the union it
is no longer a concern that the union must be pointer aligned on most
architectures because the union follows immediately after si_addr
which is a pointer.
This change results in a difference in siginfo field placement on
sparc and alpha for the fields si_addr_lsb, si_lower, si_upper,
si_pkey, and si_perf. These architectures do not implement the
signals that would use si_addr_lsb, si_lower, si_upper, si_pkey, and
si_perf. Further these architecture have not yet implemented the
userspace that would use si_perf.
The point of this change is in fact to correct these placement issues
before sparc or alpha grow userspace that cares. This change was
discussed[1] and the agreement is that this change is currently safe.
[1]: https://lkml.kernel.org/r/CAK8P3a0+uKYwL1NhY6Hvtieghba2hKYGD6hcKx5n8=4Gtt+pHA@mail.gmail.com
Acked-by: Marco Elver <elver@google.com>
v1: https://lkml.kernel.org/r/m1tunns7yf.fsf_-_@fess.ebiederm.org
v2: https://lkml.kernel.org/r/20210505141101.11519-5-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20210517195748.8880-1-ebiederm@xmission.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/signal.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index c3017aa8024a..65888aec65a0 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -4607,6 +4607,7 @@ static inline void siginfo_buildtime_checks(void) /* sigfault */ CHECK_OFFSET(si_addr); + CHECK_OFFSET(si_trapno); CHECK_OFFSET(si_addr_lsb); CHECK_OFFSET(si_lower); CHECK_OFFSET(si_upper); |