stacktrace: Unbreak stack_trace_save_tsk_reliable()
Miroslav reported that the livepatch self-tests were failing, specifically a case in which the consistency model ensures that a current executing function is not allowed to be patched, "TEST: busy target module". Recent renovations of stack_trace_save_tsk_reliable() left it returning only an -ERRNO success indication in some configuration combinations: klp_check_stack() ret = stack_trace_save_tsk_reliable() #ifdef CONFIG_ARCH_STACKWALK && CONFIG_HAVE_RELIABLE_STACKTRACE stack_trace_save_tsk_reliable() ret = arch_stack_walk_reliable() return 0 return -EINVAL ... return ret; ... if (ret < 0) /* stack_trace_save_tsk_reliable error */ nr_entries = ret; << 0 Previously (and currently for !CONFIG_ARCH_STACKWALK && CONFIG_HAVE_RELIABLE_STACKTRACE) stack_trace_save_tsk_reliable() returned the number of entries that it consumed in the passed storage array. In the case of the above config and trace, be sure to return the stacktrace_cookie.len on stack_trace_save_tsk_reliable() success. Fixes: 25e39e32 ("livepatch: Simplify stack trace retrieval") Reported-by:Miroslav Benes <mbenes@suse.cz> Signed-off-by:
Joe Lawrence <joe.lawrence@redhat.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Reviewed-by:
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Acked-by:
Josh Poimboeuf <jpoimboe@redhat.com> Cc: live-patching@vger.kernel.org Cc: jikos@kernel.org Cc: pmladek@suse.com Link: https://lkml.kernel.org/r/20190517185117.24642-1-joe.lawrence@redhat.com
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