From: Martin Ågren Date: Wed, 1 Nov 2017 20:45:06 +0000 (+0100) Subject: grep: take the read-lock when adding a submodule X-Git-Tag: v2.15.1~34^2 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=9560e6245a1a0b7483a57d7018e5b7a852fdba62;p=thirdparty%2Fgit.git grep: take the read-lock when adding a submodule With --recurse-submodules, we add each submodule that we encounter to the list of alternate object databases. With threading, our changes to the list are not protected against races. Indeed, ThreadSanitizer reports a race when we call `add_to_alternates_memory()` around the same time that another thread is reading in the list through `read_sha1_file()`. Take the grep read-lock while adding the submodule. The lock is used to serialize uses of non-thread-safe parts of Git's API, including `read_sha1_file()`. Helped-by: Brandon Williams Signed-off-by: Martin Ågren Acked-by: Brandon Williams Reviewed-by: Jeff King Signed-off-by: Junio C Hamano --- diff --git a/builtin/grep.c b/builtin/grep.c index cd0e51f3c0..6946cf4bbc 100644 --- a/builtin/grep.c +++ b/builtin/grep.c @@ -431,7 +431,9 @@ static int grep_submodule(struct grep_opt *opt, struct repository *superproject, * store is no longer global and instead is a member of the repository * object. */ + grep_read_lock(); add_to_alternates_memory(submodule.objectdir); + grep_read_unlock(); if (oid) { struct object *object;