[SRU][jammy][PATCH v2 5/5] s390/unwind: fix fgraph return address recovery

[John Cabaj]

From: Sumanth Korikkar <sumanthk at linux.ibm.com>

BugLink: https://bugs.launchpad.net/bugs/2013603 (Kernel livepatch ftrace graph fix)

When HAVE_FUNCTION_GRAPH_RET_ADDR_PTR is defined, the return
address to the fgraph caller is recovered by tagging it along with the
stack pointer of ftrace stack. This makes the stack unwinding more
reliable.

When the fgraph return address is modified to return_to_handler,
ftrace_graph_ret_addr tries to restore it to the original
value using tagged stack pointer.

Fix this by passing tagged sp to ftrace_graph_ret_addr.

Fixes: d81675b60d09 ("s390/unwind: recover kretprobe modified return address in stacktrace")
Cc: <stable at vger.kernel.org> # 5.18
Reviewed-by: Vasily Gorbik <gor at linux.ibm.com>
Signed-off-by: Sumanth Korikkar <sumanthk at linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev at linux.ibm.com>
(cherry picked from commit ded466e1806686794b403ebf031133bbaca76bb2)
Signed-off-by: John Cabaj <john.cabaj at canonical.com>
---
 arch/s390/include/asm/unwind.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/include/asm/unwind.h b/arch/s390/include/asm/unwind.h
index 0bf06f1682d8..02462e7100c1 100644
--- a/arch/s390/include/asm/unwind.h
+++ b/arch/s390/include/asm/unwind.h
@@ -47,7 +47,7 @@ struct unwind_state {
 static inline unsigned long unwind_recover_ret_addr(struct unwind_state *state,
 						    unsigned long ip)
 {
-	ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, ip, NULL);
+	ip = ftrace_graph_ret_addr(state->task, &state->graph_idx, ip, (void *)state->sp);
 	if (is_kretprobe_trampoline(ip))
 		ip = kretprobe_find_ret_addr(state->task, (void *)state->sp, &state->kr_cur);
 	return ip;
-- 
2.34.1