From: zhongjiang <zhongjiang@xxxxxxxxxx> Subject: kernel/signal.c: avoid undefined behaviour in kill_something_info When running kill(72057458746458112, 0) in userspace I hit the following issue. [ 304.606353] UBSAN: Undefined behaviour in kernel/signal.c:1462:11 [ 304.612622] negation of -2147483648 cannot be represented in type 'int': [ 304.619516] CPU: 226 PID: 9849 Comm: test Tainted: G B ---- ------- 3.10.0-327.53.58.70.x86_64_ubsan+ #116 [ 304.630692] Hardware name: Huawei Technologies Co., Ltd. RH8100 V3/BC61PBIA, BIOS BLHSV028 11/11/2014 [ 304.640168] ffffffff825ded30 000000005dc276fa ffff883c3a4b7ce0 ffffffff81d6eb06 [ 304.647870] ffff883c3a4b7cf8 ffffffff81d6ebb9 ffffffff825ded20 ffff883c3a4b7de8 [ 304.655584] ffffffff81d6fc89 0000000041b58ab3 ffffffff8228d6d8 ffffffff81d6fb80 [ 304.663299] Call Trace: [ 304.665827] [<ffffffff81d6eb06>] dump_stack+0x19/0x1b [ 304.671115] [<ffffffff81d6ebb9>] ubsan_epilogue+0xd/0x50 [ 304.676668] [<ffffffff81d6fc89>] __ubsan_handle_negate_overflow+0x109/0x14e [ 304.683917] [<ffffffff81d6fb80>] ? __ubsan_handle_divrem_overflow+0x1df/0x1df [ 304.691353] [<ffffffff8134a129>] ? __inc_zone_state+0x29/0xf0 [ 304.697358] [<ffffffff813272df>] ? __lru_cache_add+0x8f/0xe0 [ 304.703272] [<ffffffff8132764e>] ? lru_cache_add+0xe/0x10 [ 304.708921] [<ffffffff812263bd>] ? map_id_up+0xad/0xe0 [ 304.714306] [<ffffffff8113126e>] SYSC_kill+0x43e/0x4d0 [ 304.725359] [<ffffffff8116e630>] ? lg_local_unlock+0x20/0xd0 [ 304.736978] [<ffffffff81130e30>] ? kill_pid+0x20/0x20 [ 304.747928] [<ffffffff81366f90>] ? __pmd_alloc+0x180/0x180 [ 304.759273] [<ffffffff8143f80b>] ? mntput+0x3b/0x70 [ 304.769919] [<ffffffff81d85c3c>] ? __do_page_fault+0x2bc/0x650 [ 304.781462] [<ffffffff8123bb47>] ? __audit_syscall_entry+0x1f7/0x2a0 [ 304.793476] [<ffffffff8113535e>] SyS_kill+0xe/0x10 [ 304.803859] [<ffffffff81d91109>] system_call_fastpath+0x16/0x1b Add code to avoid the UBSAN detection. [akpm@xxxxxxxxxxxxxxxxxxxx: tweak comment] Link: http://lkml.kernel.org/r/1496670008-59084-1-git-send-email-zhongjiang@xxxxxxxxxx Signed-off-by: zhongjiang <zhongjiang@xxxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- kernel/signal.c | 4 ++++ 1 file changed, 4 insertions(+) diff -puN kernel/signal.c~signal-avoid-undefined-behaviour-in-kill_something_info kernel/signal.c --- a/kernel/signal.c~signal-avoid-undefined-behaviour-in-kill_something_info +++ a/kernel/signal.c @@ -1402,6 +1402,10 @@ static int kill_something_info(int sig, return ret; } + /* -INT_MIN is undefined. Exclude this case to avoid a UBSAN warning */ + if (pid == INT_MIN) + return -ESRCH; + read_lock(&tasklist_lock); if (pid != -1) { ret = __kill_pgrp_info(sig, info, _ -- 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
