On Mon 07-12-15 11:27:07, Dmitry Vyukov wrote: > Hello, > > While running syzkaller fuzzer on commit > 31ade3b83e1821da5fbb2f11b5b3d4ab2ec39db8, I've hit the following UBSAN > warning. I think it can lead to an unexpected active wait loop, if > user-space expects such io_getevents to wait for a long duration but > instead it returns immediately, so user-space reissues the same call > again and again. Andrey suggested that read_events should validate > timeout with timespec_valid_strict before using it. Yup, looks correct. Will you send a patch? Honza > UBSAN: Undefined behaviour in include/linux/ktime.h:55:49 > signed integer overflow: > 1449363382000000000 + 8584381026499825158 cannot be represented in > type 'long long int' > CPU: 0 PID: 27992 Comm: syzkaller_execu Not tainted 4.4.0-rc3+ #150 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 > 0000000000000000 ffff880062ab7ae0 ffffffff82c6f2a8 0000000041b58ab3 > ffffffff8788bf8d ffffffff82c6f1f6 ffff880062ab7aa8 ffffffff88479680 > ffff880062ab7be0 7721d90fc5200e06 0000000000000001 ffff880062ab7af0 > Call Trace: > [< inline >] __dump_stack lib/dump_stack.c:15 > [<ffffffff82c6f2a8>] dump_stack+0xb2/0xfa lib/dump_stack.c:50 > [<ffffffff82d622e7>] ubsan_epilogue+0x12/0x8f lib/ubsan.c:160 > [<ffffffff82d63e58>] handle_overflow+0x22f/0x276 lib/ubsan.c:191 > [<ffffffff82d63ec9>] __ubsan_handle_add_overflow+0x2a/0x31 lib/ubsan.c:199 > [< inline >] ktime_set include/linux/ktime.h:55 > [< inline >] timespec_to_ktime include/linux/ktime.h:83 > [<ffffffff8190ca77>] read_events+0x4b7/0x560 fs/aio.c:1273 > [< inline >] SYSC_io_getevents fs/aio.c:1737 > [<ffffffff81913567>] SyS_io_getevents+0xc7/0x340 fs/aio.c:1726 > [<ffffffff868dae76>] entry_SYSCALL_64_fastpath+0x16/0x7a > arch/x86/entry/entry_64.S:185 > > Thank you > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
