Merge tag 'x86_urgent_for_v6.2_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:

 - Two fixes to correct how kprobes handles INT3 now that they're added
   by other functionality like the rethunks and not only kgdb

 - Remove __init section markings of two functions which are referenced
   by a function in the .text section

* tag 'x86_urgent_for_v6.2_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kprobes: Fix optprobe optimization check with CONFIG_RETHUNK
  x86/kprobes: Fix kprobes instruction boudary check with CONFIG_RETHUNK
  x86/calldepth: Fix incorrect init section references

3 files changed, 17 insertions, 25 deletions

diff --git a/arch/x86/kernel/callthunks.c b/arch/x86/kernel/callthunks.c
index 7d2c75ec9a8c..ffea98f9064b 100644
--- a/arch/x86/kernel/callthunks.c
+++ b/arch/x86/kernel/callthunks.c
@@ -119,7 +119,7 @@ static bool is_coretext(const struct core_text *ct, void *addr)
 	return within_module_coretext(addr);
 }
 
-static __init_or_module bool skip_addr(void *dest)
+static bool skip_addr(void *dest)
 {
 	if (dest == error_entry)
 		return true;
@@ -181,7 +181,7 @@ static const u8 nops[] = {
 	0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90, 0x90,
 };
 
-static __init_or_module void *patch_dest(void *dest, bool direct)
+static void *patch_dest(void *dest, bool direct)
 {
 	unsigned int tsize = SKL_TMPL_SIZE;
 	u8 *pad = dest - tsize;
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 66299682b6b7..b36f3c367cb2 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -37,6 +37,7 @@
 #include <linux/extable.h>
 #include <linux/kdebug.h>
 #include <linux/kallsyms.h>
+#include <linux/kgdb.h>
 #include <linux/ftrace.h>
 #include <linux/kasan.h>
 #include <linux/moduleloader.h>
@@ -281,12 +282,15 @@ static int can_probe(unsigned long paddr)
 		if (ret < 0)
 			return 0;
 
+#ifdef CONFIG_KGDB
 		/*
-		 * Another debugging subsystem might insert this breakpoint.
-		 * In that case, we can't recover it.
+		 * If there is a dynamically installed kgdb sw breakpoint,
+		 * this function should not be probed.
 		 */
-		if (insn.opcode.bytes[0] == INT3_INSN_OPCODE)
+		if (insn.opcode.bytes[0] == INT3_INSN_OPCODE &&
+		    kgdb_has_hit_break(addr))
 			return 0;
+#endif
 		addr += insn.length;
 	}
 
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index e6b8c5362b94..e57e07b0edb6 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -15,6 +15,7 @@
 #include <linux/extable.h>
 #include <linux/kdebug.h>
 #include <linux/kallsyms.h>
+#include <linux/kgdb.h>
 #include <linux/ftrace.h>
 #include <linux/objtool.h>
 #include <linux/pgtable.h>
@@ -279,19 +280,6 @@ static int insn_is_indirect_jump(struct insn *insn)
 	return ret;
 }
 
-static bool is_padding_int3(unsigned long addr, unsigned long eaddr)
-{
-	unsigned char ops;
-
-	for (; addr < eaddr; addr++) {
-		if (get_kernel_nofault(ops, (void *)addr) < 0 ||
-		    ops != INT3_INSN_OPCODE)
-			return false;
-	}
-
-	return true;
-}
-
 /* Decode whole function to ensure any instructions don't jump into target */
 static int can_optimize(unsigned long paddr)
 {
@@ -334,15 +322,15 @@ static int can_optimize(unsigned long paddr)
 		ret = insn_decode_kernel(&insn, (void *)recovered_insn);
 		if (ret < 0)
 			return 0;
-
+#ifdef CONFIG_KGDB
 		/*
-		 * In the case of detecting unknown breakpoint, this could be
-		 * a padding INT3 between functions. Let's check that all the
-		 * rest of the bytes are also INT3.
+		 * If there is a dynamically installed kgdb sw breakpoint,
+		 * this function should not be probed.
 		 */
-		if (insn.opcode.bytes[0] == INT3_INSN_OPCODE)
-			return is_padding_int3(addr, paddr - offset + size) ? 1 : 0;
-
+		if (insn.opcode.bytes[0] == INT3_INSN_OPCODE &&
+		    kgdb_has_hit_break(addr))
+			return 0;
+#endif
 		/* Recover address */
 		insn.kaddr = (void *)addr;
 		insn.next_byte = (void *)(addr + insn.length);