| Message ID | 20090916050845.GA5805@linux-sh.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
CC: Paulo Marques <pmarques@grupopie.com> (who reviewed that patch) Paul Mundt wrote: > [ I'm not sure who exactly this should go to, so I've attempted to get all of > the interested parties in the Cc. ] > > This is a re-send of a problem that I reported on August 7th, both Sam and Lai > have been unresponsive, so hopefully someone else can take a look at this. > Lai is off office and won't be back in 2 weeks, so I'm afraid he won't be responsive.. > Commit b478b782e110fdb4135caa3062b6d687e989d994 "kallsyms, tracing: > output more proper symbol name" introduces a "bugfix" that introduces > a segfault in kallsyms in my configurations. > > The cause is the introduction of prefix_underscores_count() which > attempts to count underscores, even in symbols that do not have them. > As a result, it just uselessly runs past the end of the buffer until it > crashes: > But the fix looks obviously correct, as long as @str is guaranteed to be NULL-terminated. ... > @@ -584,9 +538,14 @@ static int may_be_linker_script_provide_symbol(const struct sym_entry *se) > static int prefix_underscores_count(const char *str) > { > const char *tail = str; > + size_t len = strlen(str); > + > + while (*tail != '_') { > + if (!len--) > + return 0; > > - while (*tail != '_') > tail++; > + } Can be simplified as: while (*tail != '\0' && *tail != '_') tail++; But..as the name "prefix_underscores_count" suggests, shouldn't it be: while (*tail == '_') tail++; ?? > > return tail - str; > } -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/scripts/kallsyms.c b/scripts/kallsyms.c index 64343cc..f1d44b2 100644 --- a/scripts/kallsyms.c +++ b/scripts/kallsyms.c @@ -584,9 +538,14 @@ static int may_be_linker_script_provide_symbol(const struct sym_entry *se) static int prefix_underscores_count(const char *str) { const char *tail = str; + size_t len = strlen(str); + + while (*tail != '_') { + if (!len--) + return 0; - while (*tail != '_') tail++; + } return tail - str; }
[ I'm not sure who exactly this should go to, so I've attempted to get all of the interested parties in the Cc. ] This is a re-send of a problem that I reported on August 7th, both Sam and Lai have been unresponsive, so hopefully someone else can take a look at this. Commit b478b782e110fdb4135caa3062b6d687e989d994 "kallsyms, tracing: output more proper symbol name" introduces a "bugfix" that introduces a segfault in kallsyms in my configurations. The cause is the introduction of prefix_underscores_count() which attempts to count underscores, even in symbols that do not have them. As a result, it just uselessly runs past the end of the buffer until it crashes: CC init/version.o LD init/built-in.o LD .tmp_vmlinux1 KSYM .tmp_kallsyms1.S /bin/sh: line 1: 16934 Done sh-linux-gnu-nm -n .tmp_vmlinux1 16935 Segmentation fault | scripts/kallsyms > .tmp_kallsyms1.S make: *** [.tmp_kallsyms1.S] Error 139 This adds a strlen iterator that bails out if nothing is found in the string, which fixes up the observed segfaults. Signed-off-by: Paul Mundt <lethal@linux-sh.org> --- I've uploaded a sample problematic symbol list to: http://userweb.kernel.org/~lethal/symbol-list.gz that one can pipe in to scripts/kallsyms to reproduce the fault, incase someone wants to make a better fix. I'm at a loss as to why no one else has reported this yet. scripts/kallsyms.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html