Messages in this thread | | | Subject | Re: [PATCH] trace, kasan: silence Kasan warning in check_stack | From | Andrey Ryabinin <> | Date | Tue, 9 Feb 2016 16:40:12 +0300 |
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On 02/08/2016 09:39 PM, Yang Shi wrote: > When enabling stack trace via "echo 1 > /proc/sys/kernel/stack_tracer_enabled", > the below KASAN warning is triggered: > > BUG: KASAN: stack-out-of-bounds in check_stack+0x344/0x848 at addr ffffffc0689ebab8 > Read of size 8 by task ksoftirqd/4/29 > page:ffffffbdc3a27ac0 count:0 mapcount:0 mapping: (null) index:0x0 > flags: 0x0() > page dumped because: kasan: bad access detected > CPU: 4 PID: 29 Comm: ksoftirqd/4 Not tainted 4.5.0-rc1 #129 > Hardware name: Freescale Layerscape 2085a RDB Board (DT) > Call trace: > [<ffffffc000091300>] dump_backtrace+0x0/0x3a0 > [<ffffffc0000916c4>] show_stack+0x24/0x30 > [<ffffffc0009bbd78>] dump_stack+0xd8/0x168 > [<ffffffc000420bb0>] kasan_report_error+0x6a0/0x920 > [<ffffffc000421688>] kasan_report+0x70/0xb8 > [<ffffffc00041f7f0>] __asan_load8+0x60/0x78 > [<ffffffc0002e05c4>] check_stack+0x344/0x848 > [<ffffffc0002e0c8c>] stack_trace_call+0x1c4/0x370 > [<ffffffc0002af558>] ftrace_ops_no_ops+0x2c0/0x590 > [<ffffffc00009f25c>] ftrace_graph_call+0x0/0x14 > [<ffffffc0000881bc>] fpsimd_thread_switch+0x24/0x1e8 > [<ffffffc000089864>] __switch_to+0x34/0x218 > [<ffffffc0011e089c>] __schedule+0x3ac/0x15b8 > [<ffffffc0011e1f6c>] schedule+0x5c/0x178 > [<ffffffc0001632a8>] smpboot_thread_fn+0x350/0x960 > [<ffffffc00015b518>] kthread+0x1d8/0x2b0 > [<ffffffc0000874d0>] ret_from_fork+0x10/0x40 > Memory state around the buggy address: > ffffffc0689eb980: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f4 f4 f4 > ffffffc0689eba00: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 >> ffffffc0689eba80: 00 00 f1 f1 f1 f1 00 f4 f4 f4 f3 f3 f3 f3 00 00 > ^ > ffffffc0689ebb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffffffc0689ebb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > > The stacker tracer traverses the whole kernel stack when saving the max stack > trace. It may touch the stack red zones to cause the warning. So, just disable > the instrumentation to silence the warning. > > Signed-off-by: Yang Shi <yang.shi@linaro.org>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
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