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| author | Mark Johnston <markj@FreeBSD.org> | 2023-10-16 17:23:40 +0000 |
|---|---|---|
| committer | Mark Johnston <markj@FreeBSD.org> | 2023-10-24 13:20:55 +0000 |
| commit | 53f62d1c9a9cce1ba1e04fe68c5ae3e5a9a2e656 (patch) | |
| tree | 44170876d8dc6368025ed88d76d512c53d30ebbc | |
| parent | 501e1152d2a047f8ff8fba6e6efbd2d5e9872738 (diff) | |
| download | src-53f62d1c9a9cce1ba1e04fe68c5ae3e5a9a2e656.tar.gz src-53f62d1c9a9cce1ba1e04fe68c5ae3e5a9a2e656.zip | |
witness: Unconditionally initialize out-params for witness_save()
As of LLVM 16, the -fsanitize-memory-param-retval option is set to true
by default, meaning that MSan will eagerly report uninitialized function
parameters and return values, even if they are not used. A
witness_save()/witness_restore() call pair fails this test since
witness_save() may return before saving file and line number
information.
Modify witness_save() to initialize the out-params unconditionally; this
appears to be the only instance of the problem triggered when booting to
a login prompt, so let's just address it directly.
Sponsored by: Klara, Inc.
Sponsored by: Juniper Networks, Inc.
MFC after: 1 week
(cherry picked from commit 7123222220aa563dc16bf1989d335722e4ff57a6)
| -rw-r--r-- | sys/kern/subr_witness.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/sys/kern/subr_witness.c b/sys/kern/subr_witness.c index d4ab085197f4..5b9f8afd9565 100644 --- a/sys/kern/subr_witness.c +++ b/sys/kern/subr_witness.c @@ -2362,6 +2362,10 @@ witness_save(struct lock_object *lock, const char **filep, int *linep) struct lock_instance *instance; struct lock_class *class; + /* Initialize for KMSAN's benefit. */ + *filep = NULL; + *linep = 0; + /* * This function is used independently in locking code to deal with * Giant, SCHEDULER_STOPPED() check can be removed here after Giant |