[PATCH] sparc32: Avoid NULL pointer dereference in fault handler

[Ludwig Rydberg]

Add a null pointer check for the return value of
search_exception_tables() to avoid dereferencing it if no entry is found.
Without this check, the system will crash silently without providing
any fault information to the user.

Fixes: b4edf06c8aaa ("sparc32: switch to generic extables")
Signed-off-by: Ludwig Rydberg <ludwig.rydberg@xxxxxxxxxxx>
---
 arch/sparc/mm/fault_32.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c
index 86a831ebd8c8..4cfff3d36a99 100644
--- a/arch/sparc/mm/fault_32.c
+++ b/arch/sparc/mm/fault_32.c
@@ -232,15 +232,17 @@ asmlinkage void do_sparc_fault(struct pt_regs *regs, int text_fault, int write,
 		const struct exception_table_entry *entry;
 
 		entry = search_exception_tables(regs->pc);
+		if (entry) {
 #ifdef DEBUG_EXCEPTIONS
-		printk("Exception: PC<%08lx> faddr<%08lx>\n",
-		       regs->pc, address);
-		printk("EX_TABLE: insn<%08lx> fixup<%08x>\n",
-			regs->pc, entry->fixup);
+			printk("Exception: PC<%08lx> faddr<%08lx>\n",
+			       regs->pc, address);
+			printk("EX_TABLE: insn<%08lx> fixup<%08x>\n",
+				regs->pc, entry->fixup);
 #endif
-		regs->pc = entry->fixup;
-		regs->npc = regs->pc + 4;
-		return;
+			regs->pc = entry->fixup;
+			regs->npc = regs->pc + 4;
+			return;
+		}
 	}
 
 	unhandled_fault(address, tsk, regs);

base-commit: cee9395acd8043be0644b25c34bfa86623f2b935
-- 
2.35.3