Hi, Greg,
Please use: https://lore.kernel.org/loongarch/20260106031300.961198-1-chenhuacai@loongso...
Huacai
-----原始邮件----- 发件人: gregkh@linuxfoundation.org 发送时间:2026-01-05 20:58:41 (星期一) 收件人: duanchenghao@kylinos.cn, chenhuacai@loongson.cn 抄送: stable@vger.kernel.org 主题: FAILED: patch "[PATCH] LoongArch: Refactor register restoration in" failed to apply to 6.6-stable tree
The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 45cb47c628dfbd1994c619f3eac271a780602826 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2026010541-varmint-tablet-f295@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 45cb47c628dfbd1994c619f3eac271a780602826 Mon Sep 17 00:00:00 2001 From: Chenghao Duan duanchenghao@kylinos.cn Date: Wed, 31 Dec 2025 15:19:20 +0800 Subject: [PATCH] LoongArch: Refactor register restoration in ftrace_common_return
Refactor the register restoration sequence in the ftrace_common_return function to clearly distinguish between the logic of normal returns and direct call returns in function tracing scenarios. The logic is as follows:
- In the case of a normal return, the execution flow returns to the
traced function, and ftrace must ensure that the register data is consistent with the state when the function was entered.
ra = parent return address; t0 = traced function return address.
- In the case of a direct call return, the execution flow jumps to the
custom trampoline function, and ftrace must ensure that the register data is consistent with the state when ftrace was entered.
ra = traced function return address; t0 = parent return address.
Cc: stable@vger.kernel.org Fixes: 9cdc3b6a299c ("LoongArch: ftrace: Add direct call support") Signed-off-by: Chenghao Duan duanchenghao@kylinos.cn Signed-off-by: Huacai Chen chenhuacai@loongson.cn
diff --git a/arch/loongarch/kernel/mcount_dyn.S b/arch/loongarch/kernel/mcount_dyn.S index d6b474ad1d5e..5729c20e5b8b 100644 --- a/arch/loongarch/kernel/mcount_dyn.S +++ b/arch/loongarch/kernel/mcount_dyn.S @@ -94,7 +94,6 @@ SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL)
- at the callsite, so there is no need to restore the T series regs.
*/ ftrace_common_return:
- PTR_L ra, sp, PT_R1 PTR_L a0, sp, PT_R4 PTR_L a1, sp, PT_R5 PTR_L a2, sp, PT_R6
@@ -104,12 +103,17 @@ ftrace_common_return: PTR_L a6, sp, PT_R10 PTR_L a7, sp, PT_R11 PTR_L fp, sp, PT_R22
- PTR_L t0, sp, PT_ERA PTR_L t1, sp, PT_R13
- PTR_ADDI sp, sp, PT_SIZE bnez t1, .Ldirect
- PTR_L ra, sp, PT_R1
- PTR_L t0, sp, PT_ERA
- PTR_ADDI sp, sp, PT_SIZE jr t0
.Ldirect:
- PTR_L t0, sp, PT_R1
- PTR_L ra, sp, PT_ERA
- PTR_ADDI sp, sp, PT_SIZE jr t1
SYM_CODE_END(ftrace_common) @@ -161,6 +165,8 @@ SYM_CODE_END(return_to_handler) #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS SYM_CODE_START(ftrace_stub_direct_tramp) UNWIND_HINT_UNDEFINED
- jr t0
- move t1, ra
- move ra, t0
- jr t1
SYM_CODE_END(ftrace_stub_direct_tramp) #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
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