tree f25360ff71d3cfaa7367fa48767744713aa3eda0
parent 0b1ceda838b6a576dbd1aa782efa4eae4bcaa4bf
author Masami Hiramatsu <mhiramat@kernel.org> 1634777717 +0900
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1637923228 +0100

ARM: clang: Do not rely on lr register for stacktrace

[ Upstream commit b3ea5d56f212ad81328c82454829a736197ebccc ]

Currently the stacktrace on clang compiled arm kernel uses the 'lr'
register to find the first frame address from pt_regs. However, that
is wrong after calling another function, because the 'lr' register
is used by 'bl' instruction and never be recovered.

As same as gcc arm kernel, directly use the frame pointer (r11) of
the pt_regs to find the first frame address.

Note that this fixes kretprobe stacktrace issue only with
CONFIG_UNWINDER_FRAME_POINTER=y. For the CONFIG_UNWINDER_ARM,
we need another fix.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>