s390/ftrace: Fix return address recovery of traced function
When fgraph is enabled the traced function return address is replaced with
trampoline return_to_handler(). The original return address of the traced
function is saved in per task return stack along with a stack pointer for
reliable stack unwinding via function_graph_enter_regs().
During stack unwinding e.g. for livepatching, ftrace_graph_ret_addr()
identifies the original return address of the traced function with the
saved stack pointer.
With a recent change, the stack pointers passed to ftrace_graph_ret_addr()
and function_graph_enter_regs() do not match anymore, and therefore the
original return address is not found.
Pass the correct stack pointer to function_graph_enter_regs() to fix this.
Fixes: 7495e179b478 ("s390/tracing: Enable HAVE_FTRACE_GRAPH_FUNC")
Reviewed-by: Heiko Carstens <[email protected]>
Signed-off-by: Sumanth Korikkar <[email protected]>
Signed-off-by: Vasily Gorbik <[email protected]>
1 file changed
