[PATCH 2/4] bootargs: fix double free in linux_bootargs_get()

[Sascha Hauer]

linux_bootargs_get() frees the previously generated bootargs before
building them again. When no global.linux.bootargs.* variables exist,
it returns the legacy bootargs environment variable instead, without
resetting linux_bootargs. The next call then frees the same pointer a
second time.

This is easily triggered by fixing up the device tree a couple of
times, e.g. on sandbox:

  global linux.bootargs.base=console=x; of_dump -F /chosen
  global -r linux.bootargs.base; of_dump -F /chosen
  of_dump -F /chosen

Fix this by setting linux_bootargs to NULL after freeing it.

Fixes: ee4cab9e5874 ("booting: more flexible Linux bootargs generation")
Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 common/bootargs.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/common/bootargs.c b/common/bootargs.c
index 36528b8b58..6373d9ccb1 100644
--- a/common/bootargs.c
+++ b/common/bootargs.c
@@ -32,6 +32,7 @@ const char *linux_bootargs_get(void)
 		return linux_bootargs;
 
 	free(linux_bootargs);
+	linux_bootargs = NULL;
 
 	bootargs = globalvar_get_match("linux.bootargs.", " ");
 	if (!strlen(bootargs)) {

-- 
2.47.3