Re: BUG: KASAN: stack-out-of-bounds in unwind_next_frame()

[Thomas Gleixner]

Alex,

On Mon, 1 Apr 2019, 573149609 wrote:

> In 5.1-rc2:
> [   66.801925] BUG: KASAN: stack-out-of-bounds in unwind_next_frame+0x177b/0x19e0
> [   66.801925] Read of size 8 at addr ffff88806d007c50 by task syz-executor374/5016
> [   66.801925] CPU: 0 PID: 5016 Comm: syz-executor374 Not tainted 5.1.0-rc2 #1
> [   66.801925]  dump_stack+0xca/0x13e
> [   66.801925]  ? unwind_next_frame+0x177b/0x19e0
> [   66.801925]  ? entry_SYSCALL_64_after_hwframe+0x49/0xbe
> [   66.801925]  ? perf_prepare_sample+0x83a/0x15a0
> [   66.801925]  ? deref_stack_reg+0xe0/0xe0
> [   66.801925]  ? lock_downgrade+0x620/0x620
> [   66.801925]  ? entry_SYSCALL_64_after_hwframe+0x49/0xbe
> [   66.801925]  perf_callchain_kernel+0x400/0x5b0
> .......
> [   66.801925] Memory state around the buggy address:
> [   66.801925]  ffff88806d007b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [   66.801925]  ffff88806d007b80: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
> [   66.801925] >ffff88806d007c00: 04 f2 f2 f2 f2 f2 f2 f2 00 f2 f2 f2 00 00 00 00
> [   66.801925]                                                  ^
> [   66.801925]  ffff88806d007c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> [   66.801925]  ffff88806d007d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> 
> And I also tested this problem on 5.1-rc3:

> [65.871020]BUG: KASAN: stack-out-of-bounds in unwind_next_frame+0x177b/0x19e0
> [65.871020]Read of size 8 at addr ffff888067657988 by task syz-executor798/206

....

Unfortunately this does not reproduce. Please provide your kernel config.

Thanks,

	tglx