Re: git fails: segfault at 0 ip 00000000004076d5 sp 00007fff7806ebc0
- From
Erik Faye-Lund <kusmabite@gmail.com>
- Date
- Oct 12, 2012, 16:29 UTC
- Message-ID
- <CABPQNSYyh-gk8aD9SKLzo0MDBkGECthdGZiT1mB1pA0ajdB8Cw@mail.gmail.com>
- In-Reply-To
- <CAJa+X0MefHXTu_D7-SN8itQVO4sMyc4O7=bK=-sUP+W4GHOu9g@mail.gmail.com>
On Fri, Oct 12, 2012 at 6:58 AM, Brad Hein <linuxbrad@gmail.com> wrote:
Show 25 quoted lines
> In Fedora 17 > With git-1.7.11.7-1.fc17.x86_64 (rpm) > > I try to clone a particular repository but git just returns, having > not cloned the repo. Seems like a bug. Details follow: > $ git clone http://gnuradio.org/git/gnuradio.git > > While the command fails a message is logged to syslog. Repeated > attempts to clone the repo yield the same result: > Oct 11 21:38:25 localhost kernel: [662703.442645] > git-remote-http[25796]: segfault at 0 ip 00000000004076d5 sp > 00007fff7806ebc0 error 4 in git-remote-http[400000+96000] > Oct 11 21:39:00 localhost kernel: [662737.899829] > git-remote-http[25837]: segfault at 0 ip 00000000004076d5 sp > 00007fff37c5ef20 error 4 in git-remote-http[400000+96000] > Oct 11 21:39:25 localhost kernel: [662763.341248] > git-remote-http[25873]: segfault at 0 ip 00000000004076d5 sp > 00007fff6310d470 error 4 in git-remote-http[400000+96000] > > A tcpdump reveals that the last thing the client does is requests a > file that doesn't exist on the server (404). Details are in my post on > FedoraForums: http://forums.fedoraforum.org/showthread.php?p=1607891&posted=1#post1607891 > > Problem mitigated by downgrade to "git-1.7.10.1-1.fc17.x86_64" or > "git-1.7.11.4-3.fc17.x86_64" or try to clone a different repository.
Thanks for reporting. I gave it a quick go, and the issue seems to also be present in the current 'master'.
The problem is a NULL-pointer dereferencing introduced in 8809703 ("http: factor out http error code handling"), where the code assume that slot->results still points to http_request::results. This assumption seems to be wrong.
This seems to step around the issue, but I don't know if http_request::results should be set to NULL in the first place. Jeff?
diff --git a/http.c b/http.c index 345c171..ac3ab16 100644 --- a/http.c +++ b/http.c @@ -745,10 +745,8 @@ char *get_remote_object_url(const char *url, const char *hex, return strbuf_detach(&buf, NULL); } -int handle_curl_result(struct active_request_slot *slot) +int handle_curl_result(struct active_request_slot *slot, struct slot_results *results) { - struct slot_results *results = slot->results; - if (results->curl_result == CURLE_OK) { credential_approve(&http_auth); return HTTP_OK; @@ -822,7 +820,7 @@ static int http_request(const char *url, void *result, int target, int options) if (start_active_slot(slot)) { run_active_slot(slot); - ret = handle_curl_result(slot); + ret = handle_curl_result(slot, &results); } else { error("Unable to start HTTP request for %s", url); ret = HTTP_START_FAILED; diff --git a/http.h b/http.h index 12de255..12c27fa 100644 --- a/http.h +++ b/http.h @@ -78,7 +78,7 @@ extern int start_active_slot(struct active_request_slot *slot); extern void run_active_slot(struct active_request_slot *slot); extern void finish_active_slot(struct active_request_slot *slot); extern void finish_all_active_slots(void); -extern int handle_curl_result(struct active_request_slot *slot); +extern int handle_curl_result(struct active_request_slot *slot, struct slot_results *results); #ifdef USE_CURL_MULTI extern void fill_active_slots(void); diff --git a/remote-curl.c b/remote-curl.c index 10fa8f1..42716c5 100644 --- a/remote-curl.c +++ b/remote-curl.c @@ -356,7 +356,7 @@ static int run_slot(struct active_request_slot *slot) slot->curl_result = curl_easy_perform(slot->curl); finish_active_slot(slot); - err = handle_curl_result(slot); + err = handle_curl_result(slot, &results); if (err != HTTP_OK && err != HTTP_REAUTH) { error("RPC failed; result=%d, HTTP code = %ld", results.curl_result, results.http_code);