(If this is not a correct way of reporting bug, let me know.)
[Description of the problem (cosmetic)]
If RLIMIT_FSIZE is set in the range
2**63 <= lim < RLIM_INFINITY = 2**64 - 1
then the process can't write to a file.
[Possible cause of the problem]
I guess the problem is in the function generic_write_check_limits().
In fs/read_write.c, at line 1607:
loff_t limit = rlimit(RLIMIT_FSIZE);
loff_t is signed 64 bit, and the variable 'limit' gets negative value.
But just replacing loff_t by 'unsigned long' (rlmin_t) may not work?
(due to signed --> unsigned conversion, for example).
Another possibility would be to lower RLIM_INFINITY to 2**63 - 1.
[How to reproduce]
Compile and run the following C-code:
#include <sys/resource.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
int main() {
struct rlimit rlim;
int fd;
/* set RLIMIT_FSIZE to 2**63 */
rlim.rlim_cur = rlim.rlim_max = (rlim_t)1 << 63;
if(setrlimit(RLIMIT_FSIZE, &rlim) < 0) {
perror("setrlimit"); return 1;
}
if(getrlimit(RLIMIT_FSIZE, &rlim) < 0) {
perror("getrlimit"); return 1;
}
printf("rlim_cur=%#lx\n", rlim.rlim_cur);
if((fd = creat("tmp.txt", 0600)) < 0) {
perror("creat"); return 1;
}
if(write(fd, "A", 1) < 0) { /* coredump here */
perror("write"); return 1;
}
close(fd);
return 0;
}
$ ./a.out
rlim_cur=0x8000000000000000
[1] 185552 file size limit exceeded (core dumped) ./a.out
------------------------------------------------
Jun-ichi Takimoto <takimoto-j@xxxxxxxxxxxxxxxxx>
