x86/unwind/orc: Fix error handling in __unwind_start()
authorJosh Poimboeuf <jpoimboe@redhat.com>
Thu, 14 May 2020 20:31:10 +0000 (15:31 -0500)
committerPeter Zijlstra <peterz@infradead.org>
Fri, 15 May 2020 08:35:08 +0000 (10:35 +0200)
commit71c95825289f585014fe9741b051d32a7a916680
treeb2bd84791c9e99317e70244bdcb6da2bd1e51465
parent2ef96a5bb12be62ef75b5828c0aab838ebb29cb8
x86/unwind/orc: Fix error handling in __unwind_start()

The unwind_state 'error' field is used to inform the reliable unwinding
code that the stack trace can't be trusted.  Set this field for all
errors in __unwind_start().

Also, move the zeroing out of the unwind_state struct to before the ORC
table initialization check, to prevent the caller from reading
uninitialized data if the ORC table is corrupted.

Fixes: af085d9084b4 ("stacktrace/x86: add function for detecting reliable stack traces")
Fixes: d3a09104018c ("x86/unwinder/orc: Dont bail on stack overflow")
Fixes: 98d0c8ebf77e ("x86/unwind/orc: Prevent unwinding before ORC initialization")
Reported-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/d6ac7215a84ca92b895fdd2e1aa546729417e6e6.1589487277.git.jpoimboe@redhat.com
arch/x86/kernel/unwind_orc.c