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| author | Stefan Liebler <stli@linux.ibm.com> | 2024-07-11 11:28:53 +0200 |
|---|---|---|
| committer | Stefan Liebler <stli@linux.ibm.com> | 2024-07-11 15:08:57 +0200 |
| commit | 9b7651410375ec8848a1944992d663d514db4ba7 (patch) | |
| tree | 8fffd0aee3fc1510bdfb93b96f44a2ceafc90bbb | |
| parent | 2e456ccf0c34a056e3ccafac4a0c7effef14d918 (diff) | |
| download | glibc-9b7651410375ec8848a1944992d663d514db4ba7.zip glibc-9b7651410375ec8848a1944992d663d514db4ba7.tar.gz glibc-9b7651410375ec8848a1944992d663d514db4ba7.tar.bz2 | |
s390x: Fix segfault in wcsncmp [BZ #31934]
The z13/vector-optimized wcsncmp implementation segfaults if n=1
and there is only one character (equal on both strings) before
the page end. Then it loads and compares one character and misses
to check n again. The following load fails.
This patch removes the extra load and compare of the first character
and just start with the loop which uses vector-load-to-block-boundary.
This code-path also checks n.
With this patch both tests are passing:
- the simplified one mentioned in the bugzilla 31934
- the full one in Florian Weimer's patch:
"manual: Document a GNU extension for strncmp/wcsncmp"
(https://patchwork.sourceware.org/project/glibc/patch/874j9eml6y.fsf@oldenburg.str.redhat.com/):
On s390x-linux-gnu (z16), the new wcsncmp test fails due to bug 31934.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
| -rw-r--r-- | sysdeps/s390/wcsncmp-vx.S | 10 |
1 files changed, 1 insertions, 9 deletions
diff --git a/sysdeps/s390/wcsncmp-vx.S b/sysdeps/s390/wcsncmp-vx.S index bf6dfa6..8b08156 100644 --- a/sysdeps/s390/wcsncmp-vx.S +++ b/sysdeps/s390/wcsncmp-vx.S @@ -59,14 +59,7 @@ ENTRY(WCSNCMP_Z13) sllg %r4,%r4,2 /* Convert character-count to byte-count. */ locgrne %r4,%r1 /* Use max byte-count, if bit 0/1 was one. */ - /* Check first character without vector load. */ - lghi %r5,4 /* current_len = 4 bytes. */ - /* Check s1/2[0]. */ - lt %r0,0(%r2) - l %r1,0(%r3) - je .Lend_cmp_one_char - crjne %r0,%r1,.Lend_cmp_one_char - + lghi %r5,0 /* current_len = 0 bytes. */ .Lloop: vlbb %v17,0(%r5,%r3),6 /* Load s2 to block boundary. */ vlbb %v16,0(%r5,%r2),6 /* Load s1 to block boundary. */ @@ -167,7 +160,6 @@ ENTRY(WCSNCMP_Z13) srl %r4,2 /* And convert it to character-index. */ vlgvf %r0,%v16,0(%r4) /* Load character-values. */ vlgvf %r1,%v17,0(%r4) -.Lend_cmp_one_char: cr %r0,%r1 je .Lend_equal lghi %r2,1 |