On Tue, Sep 5, 2017 at 9:30 PM, Shankara Pailoor <[email protected]> wrote: > Hi, > > I encountered this bug while fuzzing linux kernel 4.13-rc7 with syzkaller. > > ================================================================================ > UBSAN: Undefined behaviour in ./include/linux/time.h:233:27 > signed integer overflow: > 8391720337152500783 * 1000000000 cannot be represented in type 'long int' > CPU: 0 PID: 31798 Comm: syz-executor2 Not tainted 4.13.0-rc7 #2 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > Ubuntu-1.8.2-1ubuntu1 04/01/2014 > Call Trace: > __dump_stack lib/dump_stack.c:16 [inline] > dump_stack+0xf7/0x1ae lib/dump_stack.c:52 > ubsan_epilogue+0x12/0x8f lib/ubsan.c:164 > handle_overflow+0x21e/0x292 lib/ubsan.c:195 > __ubsan_handle_mul_overflow+0x2a/0x3e lib/ubsan.c:219 > timespec_to_ns include/linux/time.h:233 [inline] > posix_cpu_timer_set+0xb5c/0xf20 kernel/time/posix-cpu-timers.c:686 > do_timer_settime+0x1f4/0x390 kernel/time/posix-timers.c:890 > SYSC_timer_settime kernel/time/posix-timers.c:916 [inline] > SyS_timer_settime+0xea/0x170 kernel/time/posix-timers.c:902 > entry_SYSCALL_64_fastpath+0x18/0xad > RIP: 0033:0x451e59 > RSP: 002b:00007fb62af4fc08 EFLAGS: 00000216 ORIG_RAX: 00000000000000df > RAX: ffffffffffffffda RBX: 0000000000718000 RCX: 0000000000451e59 > RDX: 0000000020006000 RSI: 0000000000000000 RDI: 0000000000000000 > RBP: 0000000000000046 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000020003fe0 R11: 0000000000000216 R12: 00000000004be920 > R13: 00000000ffffffff R14: ffffffffffffffff R15: 0000000000000000 > ================================================================================
Looks similar to the issue Thomas fixed here: https://patchwork.kernel.org/patch/9799827/ Thomas: Should we change timespec_to_ns() to use the same transition internally rather then trying to track all the callers? thanks -john
