The patch titled brk: fix min_brk lower bound computation for COMPAT_BRK has been removed from the -mm tree. Its filename was brk-fix-min_brk-lower-bound-computation-for-compat_brk.patch This patch was dropped because it was merged into mainline or a subsystem tree The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: brk: fix min_brk lower bound computation for COMPAT_BRK From: Jiri Kosina <jkosina@xxxxxxx> Even if CONFIG_COMPAT_BRK is set in the kernel configuration, it can still be overriden by randomize_va_space sysctl. If this is the case, the min_brk computation in sys_brk() implementation is wrong, as it solely takes into account COMPAT_BRK setting, assuming that brk start is not randomized. But that might not be the case if randomize_va_space sysctl has been set to '2' at the time the binary has been loaded from disk. In such case, the check has to be done in a same way as in !CONFIG_COMPAT_BRK case. In addition to that, the check for the COMPAT_BRK case introduced back in a5b4592c ("brk: make sys_brk() honor COMPAT_BRK when computing lower bound") is slightly wrong -- the lower bound shouldn't be mm->end_code, but mm->end_data instead, as that's where the legacy applications expect brk section to start (i.e. immediately after last global variable). [akpm@xxxxxxxxxxxxxxxxxxxx: fix comment] Signed-off-by: Jiri Kosina <jkosina@xxxxxxx> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/mmap.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff -puN mm/mmap.c~brk-fix-min_brk-lower-bound-computation-for-compat_brk mm/mmap.c --- a/mm/mmap.c~brk-fix-min_brk-lower-bound-computation-for-compat_brk +++ a/mm/mmap.c @@ -254,7 +254,15 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) down_write(&mm->mmap_sem); #ifdef CONFIG_COMPAT_BRK - min_brk = mm->end_code; + /* + * CONFIG_COMPAT_BRK can still be overridden by setting + * randomize_va_space to 2, which will still cause mm->start_brk + * to be arbitrarily shifted + */ + if (mm->start_brk > PAGE_ALIGN(mm->end_data)) + min_brk = mm->start_brk; + else + min_brk = mm->end_data; #else min_brk = mm->start_brk; #endif _ Patches currently in -mm which might be from jkosina@xxxxxxx are origin.patch linux-next.patch jbd-remove-dependency-on-__gfp_nofail.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html