On Tue, 2 Feb 2016, Dmitry Vyukov wrote: > If the following program run in a parallel loop, eventually it leaves > hanged uninterruptable tasks on mmap_sem.
I am now able to reproduce the issue and will be looking into it. [ .. snip .. ] > // autogenerated by syzkaller (http://github.com/google/syzkaller) > #include <pthread.h> > #include <stdint.h> > #include <string.h> > #include <sys/syscall.h> > #include <unistd.h> > > #ifndef SYS_mlock2 > #define SYS_mlock2 325 > #endif > > long r[7]; > > void* thr(void* arg) > { > switch ((long)arg) { > case 0: > r[0] = syscall(SYS_mmap, 0x20000000ul, 0x1000ul, 0x3ul, 0x32ul, > 0xfffffffffffffffful, 0x0ul); > break; > case 1: > memcpy((void*)0x20000000, "\x2f\x64\x65\x76\x2f\x66\x64\x23", 8); The memcpy() can be removed and the problem still triggers reliably for me. > case 3: > r[4] = syscall(SYS_mmap, 0x20002000ul, 0x1000ul, 0x3ul, 0x812ul, > r[2], 0x0ul); 0x812 made me wonder (it's not really meaningful flags value), but the bug triggers also with 0x12. -- Jiri Kosina SUSE Labs
