path: root/grep.c
diff options
authorÆvar Arnfjörð Bjarmason <>2017-11-23 14:16:58 (GMT)
committerJunio C Hamano <>2017-11-24 07:12:26 (GMT)
commita25b9085043b8029169b4d5b172b78ca3f38fb37 (patch)
tree806946c9755062cb3a37f2c68f81429e01311ead /grep.c
parentce9a257031ca1cf3496c5bb1cd0d4b5ecb8379f2 (diff)
grep: fix segfault under -P + PCRE2 <=10.30 + (*NO_JIT)
Fix a bug in the compilation of PCRE2 patterns under JIT (the most common runtime configuration). Any pattern with a (*NO_JIT) verb would segfault in any currently released PCRE2 version: $ git grep -P '(*NO_JIT)hi.*there' Segmentation fault That this segfaulted was a bug in PCRE2 itself, after reporting it[1] on pcre-dev it's been fixed in a yet-to-be-released version of PCRE (presumably released first as 10.31). Now it'll die with: $ git grep -P '(*NO_JIT)hi.*there' fatal: pcre2_jit_match failed with error code -45: bad JIT option But the cause of the bug is in our own code dating back to my 94da9193a6 ("grep: add support for PCRE v2", 2017-06-01). As explained at more length in the comment being added here, it isn't sufficient to just check pcre2_config() to see whether the JIT should be used, pcre2_pattern_info() also has to be asked. This is something I discovered myself when fiddling around with PCRE2 verbs in patterns passed to git. I don't expect that any user of git has encountered this given the obscurity of passing PCRE2 verbs through to the library, along with the relative obscurity of (*NO_JIT) itself. 1. "How am I supposed to use PCRE2 JIT in the face of (*NO_JIT) ?" (<> & on the pcre-dev mailing list Signed-off-by: Ævar Arnfjörð Bjarmason <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'grep.c')
1 files changed, 26 insertions, 0 deletions
diff --git a/grep.c b/grep.c
index d0b9b6c..e8ae0b5 100644
--- a/grep.c
+++ b/grep.c
@@ -477,6 +477,8 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
int options = PCRE2_MULTILINE;
const uint8_t *character_tables = NULL;
int jitret;
+ int patinforet;
+ size_t jitsizearg;
@@ -511,6 +513,30 @@ static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt
jitret = pcre2_jit_compile(p->pcre2_pattern, PCRE2_JIT_COMPLETE);
if (jitret)
die("Couldn't JIT the PCRE2 pattern '%s', got '%d'\n", p->pattern, jitret);
+ /*
+ * The pcre2_config(PCRE2_CONFIG_JIT, ...) call just
+ * tells us whether the library itself supports JIT,
+ * but to see whether we're going to be actually using
+ * JIT we need to extract PCRE2_INFO_JITSIZE from the
+ * pattern *after* we do pcre2_jit_compile() above.
+ *
+ * This is because if the pattern contains the
+ * (*NO_JIT) verb (see pcre2syntax(3))
+ * pcre2_jit_compile() will exit early with 0. If we
+ * then proceed to call pcre2_jit_match() further down
+ * the line instead of pcre2_match() we'll either
+ * segfault (pre PCRE 10.31) or run into a fatal error
+ * (post PCRE2 10.31)
+ */
+ patinforet = pcre2_pattern_info(p->pcre2_pattern, PCRE2_INFO_JITSIZE, &jitsizearg);
+ if (patinforet)
+ BUG("pcre2_pattern_info() failed: %d", patinforet);
+ if (jitsizearg == 0) {
+ p->pcre2_jit_on = 0;
+ return;
+ }
p->pcre2_jit_stack = pcre2_jit_stack_create(1, 1024 * 1024, NULL);
if (!p->pcre2_jit_stack)
die("Couldn't allocate PCRE2 JIT stack");