Patch "parisc: Fix stack unwinder" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    parisc: Fix stack unwinder

to the 6.6-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     parisc-fix-stack-unwinder.patch
and it can be found in the queue-6.6 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 8d1f493be47a1f52eeaa525e02b92d0b92ca726e
Author: Guenter Roeck <linux@xxxxxxxxxxxx>
Date:   Thu Feb 15 13:51:45 2024 -0800

    parisc: Fix stack unwinder
    
    [ Upstream commit 882a2a724ee964c1ebe7268a91d5c8c8ddc796bf ]
    
    Debugging shows a large number of unaligned access traps in the unwinder
    code. Code analysis reveals a number of issues with this code:
    
    - handle_interruption is passed twice through
      dereference_kernel_function_descriptor()
    - ret_from_kernel_thread, syscall_exit, intr_return,
      _switch_to_ret, and _call_on_stack are passed through
      dereference_kernel_function_descriptor() even though they are
      not declared as function pointers.
    
    To fix the problems, drop one of the calls to
    dereference_kernel_function_descriptor() for handle_interruption,
    and compare the other pointers directly.
    
    Fixes: 6414b30b39f9 ("parisc: unwind: Avoid missing prototype warning for handle_interruption()")
    Fixes: 8e0ba125c2bf ("parisc/unwind: fix unwinder when CONFIG_64BIT is enabled")
    Cc: Helge Deller <deller@xxxxxx>
    Cc: Sven Schnelle <svens@xxxxxxxxxxxxxx>
    Cc: John David Anglin <dave.anglin@xxxxxxxx>
    Cc: Charlie Jenkins <charlie@xxxxxxxxxxxx>
    Cc: David Laight <David.Laight@xxxxxxxxxx>
    Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
    Signed-off-by: Helge Deller <deller@xxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/arch/parisc/kernel/unwind.c b/arch/parisc/kernel/unwind.c
index 27ae40a443b80..f7e0fee5ee55a 100644
--- a/arch/parisc/kernel/unwind.c
+++ b/arch/parisc/kernel/unwind.c
@@ -228,10 +228,8 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int
 #ifdef CONFIG_IRQSTACKS
 	extern void * const _call_on_stack;
 #endif /* CONFIG_IRQSTACKS */
-	void *ptr;
 
-	ptr = dereference_kernel_function_descriptor(&handle_interruption);
-	if (pc_is_kernel_fn(pc, ptr)) {
+	if (pc_is_kernel_fn(pc, handle_interruption)) {
 		struct pt_regs *regs = (struct pt_regs *)(info->sp - frame_size - PT_SZ_ALGN);
 		dbg("Unwinding through handle_interruption()\n");
 		info->prev_sp = regs->gr[30];
@@ -239,13 +237,13 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int
 		return 1;
 	}
 
-	if (pc_is_kernel_fn(pc, ret_from_kernel_thread) ||
-	    pc_is_kernel_fn(pc, syscall_exit)) {
+	if (pc == (unsigned long)&ret_from_kernel_thread ||
+	    pc == (unsigned long)&syscall_exit) {
 		info->prev_sp = info->prev_ip = 0;
 		return 1;
 	}
 
-	if (pc_is_kernel_fn(pc, intr_return)) {
+	if (pc == (unsigned long)&intr_return) {
 		struct pt_regs *regs;
 
 		dbg("Found intr_return()\n");
@@ -257,14 +255,14 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int
 	}
 
 	if (pc_is_kernel_fn(pc, _switch_to) ||
-	    pc_is_kernel_fn(pc, _switch_to_ret)) {
+	    pc == (unsigned long)&_switch_to_ret) {
 		info->prev_sp = info->sp - CALLEE_SAVE_FRAME_SIZE;
 		info->prev_ip = *(unsigned long *)(info->prev_sp - RP_OFFSET);
 		return 1;
 	}
 
 #ifdef CONFIG_IRQSTACKS
-	if (pc_is_kernel_fn(pc, _call_on_stack)) {
+	if (pc == (unsigned long)&_call_on_stack) {
 		info->prev_sp = *(unsigned long *)(info->sp - FRAME_SIZE - REG_SZ);
 		info->prev_ip = *(unsigned long *)(info->sp - FRAME_SIZE - RP_OFFSET);
 		return 1;