FAILED: patch "[PATCH] riscv: kprobes: Fix incorrect address calculation" failed to apply to 6.6-stable tree

[<gregkh@linuxfoundation.org>]

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 13134cc949148e1dfa540a0fe5dc73569bc62155
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025011231-bakery-sterling-1f23@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 13134cc949148e1dfa540a0fe5dc73569bc62155 Mon Sep 17 00:00:00 2001
From: Nam Cao <namcao@linutronix.de>
Date: Tue, 19 Nov 2024 12:10:56 +0100
Subject: [PATCH] riscv: kprobes: Fix incorrect address calculation

p->ainsn.api.insn is a pointer to u32, therefore arithmetic operations are
multiplied by four. This is clearly undesirable for this case.

Cast it to (void *) first before any calculation.

Below is a sample before/after. The dumped memory is two kprobe slots, the
first slot has

  - c.addiw a0, 0x1c (0x7125)
  - ebreak           (0x00100073)

and the second slot has:

  - c.addiw a0, -4   (0x7135)
  - ebreak           (0x00100073)

Before this patch:

(gdb) x/16xh 0xff20000000135000
0xff20000000135000:	0x7125	0x0000	0x0000	0x0000	0x7135	0x0010	0x0000	0x0000
0xff20000000135010:	0x0073	0x0010	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000

After this patch:

(gdb) x/16xh 0xff20000000125000
0xff20000000125000:	0x7125	0x0073	0x0010	0x0000	0x7135	0x0073	0x0010	0x0000
0xff20000000125010:	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000	0x0000

Fixes: b1756750a397 ("riscv: kprobes: Use patch_text_nosync() for insn slots")
Signed-off-by: Nam Cao <namcao@linutronix.de>
Cc: stable@vger.kernel.org
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20241119111056.2554419-1-namcao@linutronix.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index 380a0e8cecc0..c0738d6c6498 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -30,7 +30,7 @@ static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
 	p->ainsn.api.restore = (unsigned long)p->addr + len;
 
 	patch_text_nosync(p->ainsn.api.insn, &p->opcode, len);
-	patch_text_nosync(p->ainsn.api.insn + len, &insn, GET_INSN_LENGTH(insn));
+	patch_text_nosync((void *)p->ainsn.api.insn + len, &insn, GET_INSN_LENGTH(insn));
 }
 
 static void __kprobes arch_prepare_simulate(struct kprobe *p)