[PATCH 1/4] ftrace: Test mcount_loc addr before calling ftrace_call_addr()
Steven Rostedt
rostedt at goodmis.org
Tue Feb 25 10:20:05 PST 2025
From: Steven Rostedt <rostedt at goodmis.org>
The addresses in the mcount_loc can be zeroed and then moved by KASLR
making them invalid addresses. ftrace_call_addr() for ARM 64 expects a
valid address to kernel text. If the addr read from the mcount_loc section
is invalid, it must not call ftrace_call_addr(). Move the addr check
before calling ftrace_call_addr() in ftrace_process_locs().
Fixes: ef378c3b8233 ("scripts/sorttable: Zero out weak functions in mcount_loc table")
Reported-by: Nathan Chancellor <nathan at kernel.org>
Reported-by: "Arnd Bergmann" <arnd at arndb.de>
Tested-by: Nathan Chancellor <nathan at kernel.org>
Closes: https://lore.kernel.org/all/20250225025631.GA271248@ax162/
Closes: https://lore.kernel.org/all/91523154-072b-437b-bbdc-0b70e9783fd0@app.fastmail.com/
Signed-off-by: Steven Rostedt (Google) <rostedt at goodmis.org>
---
kernel/trace/ftrace.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 27c8def2139d..183f72cf15ed 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -7063,7 +7063,9 @@ static int ftrace_process_locs(struct module *mod,
pg = start_pg;
while (p < end) {
unsigned long end_offset;
- addr = ftrace_call_adjust(*p++);
+
+ addr = *p++;
+
/*
* Some architecture linkers will pad between
* the different mcount_loc sections of different
@@ -7075,6 +7077,8 @@ static int ftrace_process_locs(struct module *mod,
continue;
}
+ addr = ftrace_call_adjust(addr);
+
end_offset = (pg->index+1) * sizeof(pg->records[0]);
if (end_offset > PAGE_SIZE << pg->order) {
/* We should have allocated enough */
--
2.47.2
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