On 2/9/2016 9:23 AM, Will Deacon wrote:
On Tue, Feb 09, 2016 at 09:17:12AM -0800, Shi, Yang wrote:
On 2/9/2016 8:54 AM, Will Deacon wrote:
On Mon, Feb 08, 2016 at 09:13:09AM -0800, Yang Shi wrote:
When boot arm64 kernel with KASAN enabled, the below error is reported by kasan:
BUG: KASAN: out-of-bounds in unwind_frame+0xec/0x260 at addr ffffffc064d57ba0 Read of size 8 by task pidof/499 page:ffffffbdc39355c0 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x0() page dumped because: kasan: bad access detected CPU: 2 PID: 499 Comm: pidof Not tainted 4.5.0-rc1 #119 Hardware name: Freescale Layerscape 2085a RDB Board (DT) Call trace: [<ffffffc00008d078>] dump_backtrace+0x0/0x290 [<ffffffc00008d32c>] show_stack+0x24/0x30 [<ffffffc0006a981c>] dump_stack+0x8c/0xd8 [<ffffffc0002e4400>] kasan_report_error+0x558/0x588 [<ffffffc0002e4958>] kasan_report+0x60/0x70 [<ffffffc0002e3188>] __asan_load8+0x60/0x78 [<ffffffc00008c92c>] unwind_frame+0xec/0x260 [<ffffffc000087e60>] get_wchan+0x110/0x160 [<ffffffc0003b647c>] do_task_stat+0xb44/0xb68 [<ffffffc0003b7730>] proc_tgid_stat+0x40/0x50 [<ffffffc0003ac840>] proc_single_show+0x88/0xd8 [<ffffffc000345be8>] seq_read+0x370/0x770 [<ffffffc00030aba0>] __vfs_read+0xc8/0x1d8 [<ffffffc00030c0ec>] vfs_read+0x94/0x168 [<ffffffc00030d458>] SyS_read+0xb8/0x128 [<ffffffc000086530>] el0_svc_naked+0x24/0x28 Memory state around the buggy address: ffffffc064d57a80: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 f4 f4 ffffffc064d57b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffffffc064d57b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
^ffffffc064d57c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffffc064d57c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Since the shadow byte pointed by the report is 0, so it may mean it is just hit oob in non-current task. So, disable the instrumentation to silence these warnings.
Curious, but how did you trigger this? I'm just trying to confirm that mainline is affected, but my machine boots happily with KASAN and STACKTRACE selected and I can cat /proc/self/{stack,stat} quite happily.
What am I missing?
I'm using mainline 4.5-rc1 kernel with gcc 5.2. And, my rootfs is NFS mounted.
Not sure if other kernel configs, i.e tracing stuff will have impact on the trigger since I'm not using the defconfig.
If you could put your .config somewhere, that would be helpful, please.
Attached it. BTW, I run the test on LS2085a RDB board which has 8 A57 cores. Not sure if it could be reproduced on other boards easily.
Yang
Will