The patch titled Subject: lib: fix stall in __bitmap_parselist() has been added to the -mm tree. Its filename is lib-fix-stall-in-__bitmap_parselist.patch

This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/lib-fix-stall-in-__bitmap_parselist... and later at http://ozlabs.org/~akpm/mmotm/broken-out/lib-fix-stall-in-__bitmap_parselist...

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------------------------------------------------------ From: Yury Norov ynorov@caviumnetworks.com Subject: lib: fix stall in __bitmap_parselist()

syzbot is catching stalls at __bitmap_parselist() (https://syzkaller.appspot.com/bug?id=ad7e0351fbc90535558514a71cd3edc11681997...). The trigger is

unsigned long v = 0; bitmap_parselist("7:,", &v, BITS_PER_LONG);

which results in hitting infinite loop at

while (a <= b) { off = min(b - a + 1, used_size); bitmap_set(maskp, a, off); a += group_size; }

due to used_size == group_size == 0.

Link: http://lkml.kernel.org/r/20180404162647.15763-1-ynorov@caviumnetworks.com Fixes: 0a5ce0831d04382a ("lib/bitmap.c: make bitmap_parselist() thread-safe and much faster") Signed-off-by: Yury Norov ynorov@caviumnetworks.com Reported-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Reported-by: syzbot syzbot+6887cbb011c8054e8a3d@syzkaller.appspotmail.com Cc: Noam Camus noamca@mellanox.com Cc: Rasmus Villemoes linux@rasmusvillemoes.dk Cc: Matthew Wilcox mawilcox@microsoft.com Cc: Mauro Carvalho Chehab mchehab@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

lib/bitmap.c | 2 +- lib/test_bitmap.c | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-)

diff -puN lib/bitmap.c~lib-fix-stall-in-__bitmap_parselist lib/bitmap.c --- a/lib/bitmap.c~lib-fix-stall-in-__bitmap_parselist +++ a/lib/bitmap.c @@ -607,7 +607,7 @@ static int __bitmap_parselist(const char /* if no digit is after '-', it's wrong*/ if (at_start && in_range) return -EINVAL; - if (!(a <= b) || !(used_size <= group_size)) + if (!(a <= b) || group_size == 0 || !(used_size <= group_size)) return -EINVAL; if (b >= nmaskbits) return -ERANGE; diff -puN lib/test_bitmap.c~lib-fix-stall-in-__bitmap_parselist lib/test_bitmap.c --- a/lib/test_bitmap.c~lib-fix-stall-in-__bitmap_parselist +++ a/lib/test_bitmap.c @@ -255,6 +255,10 @@ static const struct test_bitmap_parselis {-EINVAL, "-1", NULL, 8, 0}, {-EINVAL, "-0", NULL, 8, 0}, {-EINVAL, "10-1", NULL, 8, 0}, + {-EINVAL, "0-31:", NULL, 8, 0}, + {-EINVAL, "0-31:0", NULL, 8, 0}, + {-EINVAL, "0-31:0/0", NULL, 8, 0}, + {-EINVAL, "0-31:1/0", NULL, 8, 0}, {-EINVAL, "0-31:10/1", NULL, 8, 0}, };

_

Patches currently in -mm which might be from ynorov@caviumnetworks.com are

lib-fix-stall-in-__bitmap_parselist.patch