From ab8a3e14e6f8e567560f664bbd29aefb306a274e Mon Sep 17 00:00:00 2001 From: KOSAKI Motohiro Date: Mon, 26 Oct 2009 16:49:58 -0700 Subject: mbind(): fix leak of never putback pages If mbind() receives an invalid address, do_mbind leaks a page. The following test program detects this leak. This patch fixes it. migrate_efault.c ======================================= #include #include #include #include #include #include #include static unsigned long pagesize; static void* make_hole_mapping(void) { void* addr; addr = mmap(NULL, pagesize*3, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, 0, 0); if (addr == MAP_FAILED) return NULL; /* make page populate */ memset(addr, 0, pagesize*3); /* make memory hole */ munmap(addr+pagesize, pagesize); return addr; } int main(int argc, char** argv) { void* addr; int ch; int node; struct bitmask *nmask = numa_allocate_nodemask(); int err; int node_set = 0; while ((ch = getopt(argc, argv, "n:")) != -1){ switch (ch){ case 'n': node = strtol(optarg, NULL, 0); numa_bitmask_setbit(nmask, node); node_set = 1; break; default: ; } } argc -= optind; argv += optind; if (!node_set) numa_bitmask_setbit(nmask, 0); pagesize = getpagesize(); addr = make_hole_mapping(); err = mbind(addr, pagesize*3, MPOL_BIND, nmask->maskp, nmask->size, MPOL_MF_MOVE_ALL); if (err) perror("mbind "); return 0; } ======================================= Signed-off-by: KOSAKI Motohiro Acked-by: Christoph Lameter Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mempolicy.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 7dd9d9f80694..d49956d30259 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1058,7 +1058,8 @@ static long do_mbind(unsigned long start, unsigned long len, if (!err && nr_failed && (flags & MPOL_MF_STRICT)) err = -EIO; - } + } else + putback_lru_pages(&pagelist); up_write(&mm->mmap_sem); mpol_put(new); -- cgit v1.2.3