2023-03-17 23:42:01

by Max Filippov

[permalink] [raw]
Subject: [PATCH] xtensa: fix KASAN report for show_stack

show_stack dumps raw stack contents which may trigger an unnecessary
KASAN report. Fix it by copying stack contents to a temporary buffer
with __memcpy and then printing that buffer instead of passing stack
pointer directly to the print_hex_dump.

Cc: [email protected]
Signed-off-by: Max Filippov <[email protected]>
---
arch/xtensa/kernel/traps.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
index cd98366a9b23..f0a7d1c2641e 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/arch/xtensa/kernel/traps.c
@@ -539,7 +539,7 @@ static size_t kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;

void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
{
- size_t len;
+ size_t len, off = 0;

if (!sp)
sp = stack_pointer(task);
@@ -548,9 +548,17 @@ void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
kstack_depth_to_print * STACK_DUMP_ENTRY_SIZE);

printk("%sStack:\n", loglvl);
- print_hex_dump(loglvl, " ", DUMP_PREFIX_NONE,
- STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE,
- sp, len, false);
+ while (off < len) {
+ u8 line[STACK_DUMP_LINE_SIZE];
+ size_t line_len = len - off > STACK_DUMP_LINE_SIZE ?
+ STACK_DUMP_LINE_SIZE : len - off;
+
+ __memcpy(line, (u8 *)sp + off, line_len);
+ print_hex_dump(loglvl, " ", DUMP_PREFIX_NONE,
+ STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE,
+ line, line_len, false);
+ off += STACK_DUMP_LINE_SIZE;
+ }
show_trace(task, sp, loglvl);
}

--
2.30.2