huge_count_read_write.c:23:9: warning: 'write' reading 4294967295 bytes from a region of size 1

From: kernel test robot
Date: Wed Jun 08 2022 - 09:29:03 EST


tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 9886142c7a2226439c1e3f7d9b69f9c7094c3ef6
commit: 678f0cdc572c5fda940cb038d70eebb8d818adc8 selftests/damon: add damon to selftests root Makefile
date: 6 weeks ago
reproduce: make O=/tmp/kselftest -C tools/testing/selftests

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

huge_count_read_write.c: In function 'write_read_with_huge_count':
>> huge_count_read_write.c:23:9: warning: 'write' reading 4294967295 bytes from a region of size 1 [-Wstringop-overread]
23 | write(filedesc, "", 0xfffffffful);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from huge_count_read_write.c:8:
/usr/include/unistd.h:367:16: note: in a call to function 'write' declared with attribute 'access (read_only, 2, 3)'
367 | extern ssize_t write (int __fd, const void *__buf, size_t __n) __wur
| ^~~~~
>> huge_count_read_write.c:25:15: warning: 'read' writing 4294967295 bytes into a region of size 25 overflows the destination [-Wstringop-overflow=]
25 | ret = read(filedesc, buf, 0xfffffffful);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
huge_count_read_write.c:14:14: note: destination object 'buf' of size 25
14 | char buf[25];
| ^~~
In file included from huge_count_read_write.c:8:
/usr/include/unistd.h:360:16: note: in a call to function 'read' declared with attribute 'access (write_only, 2, 3)'
360 | extern ssize_t read (int __fd, void *__buf, size_t __nbytes) __wur
| ^~~~

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