> In QEMU with -R <high> > > $ qemu-arm -R $(( 0x10000000 )) ./brk > mmap: 0x935000 > current brk: 0xffffffff > 00000000-00008000 ---p 00000000 00:00 0 > 00008000-00009000 r-xp 00000000 08:09 1248935408 /brk > 00009000-00010000 ---p 00000000 00:00 0 > 00010000-00011000 r--p 00000000 08:09 1248935408 /brk > 00011000-00012000 rw-p 00001000 08:09 1248935408 /brk > 00012000-00013000 ---p 00000000 00:00 0 > 00013000-00813000 rw-p 00000000 00:00 0
Would tell us a lot more if (a) you gave us the map before the strace call, and (b) the requested size wasn't the same as the default stack size. > > qemu's strace says: > 15545 mmap2(NULL,4096,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANONYMOUS,-1,0) > = 0x00834000 [...] > 15545 > mmap2(0x00005000,65536,PROT_READ|PROT_WRITE,MAP_PRIVATE|MAP_ANONYMOUS,0,0) > = 0x00935000 [...] > 15545 brk(NULL) = 0x00012000 > 15545 brk(0x00812000) = 0x00012000 This is your bug. According to the trace above, the brk call fails, but returns success anyway. A quick look at do_brk confirms this suspicion. Paul
