On 2015-02-07 13:07PM Randall S. Becker wrote: >On 2015-02-07 12:30PM Torsten Bögershausen wrote: >>On 2015-02-07 17.45, Joachim Schmitz wrote: >>> Hi there >>> >>> While investigating the problem with hung git-upload-pack we think to >>> have found a bug in wrapper.c: >>> >>> #define MAX_IO_SIZE (8*1024*1024) >>> >>> This is then used in xread() to split read()s into suitable chunks. >>> So far so good, but read() is only guaranteed to read as much as >>> SSIZE_MAX bytes at a time. And on our platform that is way lower than >>> those 8MB (only 52kB, POSIX allows it to be as small as 32k), and as a >>> (rather strange) consequence mmap() (from compat/mmap.c) fails with >>> EACCESS (why EACCESS?), because xpread() returns something > 0. >>> >>> How large is SSIZE_MAX on other platforms? What happens there if you >>> try to >>> read() more? Should't we rather use SSIZE_MAX on all platforms? If I'm >>> reading the header files right, on Linux it is LONG_MAX (2TB?), so I >>> guess we should really go for MIN(8*1024*1024,SSIZE_MAX)? >>How about changing wrapper.c like this: >>#ifndef MAX_IO_SIZE >> #define MAX_IO_SIZE (8*1024*1024) >>#endif >>---------------------
Although I do agree with Jojo, that MAX_IO_SIZE seems to be a platform constant and should be defined in terms of SSIZE_MAX. So something like: #ifndef MAX_IO_SIZE # ifdef SSIZE_MAX # define MAX_IO_SIZE (SSIZE_MAX) # else # define MAX_IO_SIZE (8*1024*1024) # endif #endif would be desirable. Cheers, Randall -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
