Dmitry Vyukov 75edb54a1d x86: Fix KASAN false positives in thread_saved_pc() ... thread_saved_pc() reads stack of a potentially running task. This can cause false KASAN stack-out-of-bounds reports, because the running task concurrently poisons and unpoisons own stack. The same happens in get_wchan(), and get get_wchan() was fixed by using READ_ONCE_NOCHECK(). Do the same here. Example KASAN report triggered by sysrq-t: BUG: KASAN: out-of-bounds in sched_show_task+0x306/0x3b0 at addr ffff880043c97c18 Read of size 8 by task syz-executor/23839 [...] page dumped because: kasan: bad access detected [...] Call Trace: [<ffffffff8175ea0e>] __asan_report_load8_noabort+0x3e/0x40 [<ffffffff813e7a26>] sched_show_task+0x306/0x3b0 [<ffffffff813e7bf4>] show_state_filter+0x124/0x1a0 [<ffffffff82d2ca00>] fn_show_state+0x10/0x20 [<ffffffff82d2cf98>] k_spec+0xa8/0xe0 [<ffffffff82d3354f>] kbd_event+0xb9f/0x4000 [<ffffffff843ca8a7>] input_to_handler+0x3a7/0x4b0 [<ffffffff843d1954>] input_pass_values.part.5+0x554/0x6b0 [<ffffffff843d29bc>] input_handle_event+0x2ac/0x1070 [<ffffffff843d3a47>] input_inject_event+0x237/0x280 [<ffffffff843e8c28>] evdev_write+0x478/0x680 [<ffffffff817ac653>] __vfs_write+0x113/0x480 [<ffffffff817ae0e7>] vfs_write+0x167/0x4a0 [<ffffffff817b13d1>] SyS_write+0x111/0x220 Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: glider@google.com Cc: kasan-dev@googlegroups.com Cc: kcc@google.com Cc: linux-kernel@vger.kernel.org Cc: ryabinin.a.a@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>		2016-02-05 08:41:52 +01:00
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asm	x86: Fix KASAN false positives in thread_saved_pc()	2016-02-05 08:41:52 +01:00
uapi/asm	* s390: Support for runtime instrumentation within guests,	2016-01-12 13:22:12 -08:00