On 12/14/2016 3:47 PM, Jake Fehr (jfehr) wrote:
Thank you for the review and the links. The crash is random. The crash
reports are coming from our error reporting system. I have gone
through our code and noticed something that might be of concern. Is it
OK to do this? All calls are on the same thread:
1.Call curl_easy_init()
2.Make a couple calls curl_easy_escape()
3.Cleanup the handle from curl_easy_init() with curl_easy_cleanup()
4.Call curl_global_init()
5.Make further calls to curl_easy_init()
The first 3 steps are used to encode proxy urls that get used in steps
5 and later. I know that this violates the guidance in the thread
safety guide below and I will fix that but I just wanted to confirm if
this could lead to errors in curl_hash_add()?
Is where it crashes random or is when it crashes random? Are you sure
you're not calling curl_easy_cleanup multiple times on the same handle?
What you're describing now is different from what you described earlier.
Calling curl_easy_escape has no bearing on the connection cache. If
you're using a CURLOPT_CONV_TO_NETWORK_FUNCTION try disabling it.
curl_global_init is not thread safe and should be called once at the
beginning of the program before other threads are created. Internally it
increments a static variable but if that variable is == 0 then goes on
to initialize libcurl and its dependencies which may not be thread safe.
If you call curl_easy_init before curl_global_init then you have the
same problem.
Try building your program and libcurl with sanitization checks, like
this for example
CFLAGS="-fsanitize=address,undefined -fno-sanitize-recover -Wformat
-Werror=format-security -Werror=array-bounds -g" \
CXXFLAGS="-fsanitize=address,undefined -fno-sanitize-recover -Wformat
-Werror=format-security -Werror=array-bounds -g" \
LDFLAGS="-fsanitize=address,undefined -fno-sanitize-recover " \
./configure --enable-debug ...
You don't need to install the debug libcurl just
LD_PRELOAD=libasan.so.2:/curlpath/lib/.libs/libcurl.so /your/app
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