fix-crash.patch

From 6752571d8d782d07537a258a1ec8919ebd1308ad Mon Sep 17 00:00:00 2001
From: Lianbo Jiang <lijiang@redhat.com>
Date: Wed, 5 Jun 2024 16:28:58 +0800
Subject: [PATCH] X86 64: fix for crash session loading failure

Kernel commit 223b5e57d0d5 ("mm/execmem, arch: convert remaining
overrides of module_alloc to execmem") makes crash session loading
failure as below:

  # ./crash -s
  crash: seek error: kernel virtual address: ffffffff826bb418  type: "page_offset_base"

For X86 64 architecture, currently crash will search for symbol
"module_load_offset" to determine if the KASLR is enabled, and go
into the relevant code block. But the symbols "module_load_offset"
has been removed since Linux v6.10-rc1, which caused the current
failure.

And this issue can occur with live debugging and core dump file
debugging.

Let's check the symbol "kaslr_regions" instead of "module_load_offset"
to fix it.

Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
---
 symbols.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/symbols.c b/symbols.c
index 107920f0..f3c94b0a 100644
--- a/symbols.c
+++ b/symbols.c
@@ -619,9 +619,9 @@ strip_symbol_end(const char *name, char *buf)
  *  or in /proc/kallsyms on a live system.
  *
  *  Setting KASLR_CHECK will trigger a search for "module_load_offset"
- *  during the initial symbol sort operation, and if found, will
- *  set (RELOC_AUTO|KASLR).  On live systems, the search is done
- *  here by checking /proc/kallsyms.
+ *  or "kaslr_regions" during the initial symbol sort operation, and
+ *  if found, will set (RELOC_AUTO|KASLR).  On live systems, the search
+ *  is done here by checking /proc/kallsyms.
  */
 static void
 kaslr_init(void)
@@ -646,7 +646,8 @@ kaslr_init(void)
 		st->_stext_vmlinux = UNINITIALIZED;
 
 	if (ACTIVE() &&   /* Linux 3.15 */
-	    (symbol_value_from_proc_kallsyms("module_load_offset") != BADVAL)) {
+	    ((symbol_value_from_proc_kallsyms("kaslr_regions") != BADVAL) ||
+	    (symbol_value_from_proc_kallsyms("module_load_offset") != BADVAL))) {
 		kt->flags2 |= (RELOC_AUTO|KASLR);
 		st->_stext_vmlinux = UNINITIALIZED;
 	}
@@ -14251,7 +14252,9 @@ numeric_forward(const void *P_x, const void *P_y)
 			st->_stext_vmlinux = valueof(y);
 	}
 	if (kt->flags2 & KASLR_CHECK) {
-		if (STREQ(x->name, "module_load_offset") || 
+		if (STREQ(x->name, "kaslr_regions") ||
+		    STREQ(y->name, "kaslr_regions") ||
+		    STREQ(x->name, "module_load_offset") ||
 		    STREQ(y->name, "module_load_offset")) {
 			kt->flags2 &= ~KASLR_CHECK;
 			kt->flags2 |= (RELOC_AUTO|KASLR);