6.6-stable review patch. If anyone has any objections, please let me know.
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From: Mickaël Salaün mic@digikod.net
[ Upstream commit f8aa1b98ce40184521ed95ec26cc115a255183b2 ]
There is a race condition when a kthread finishes after the deadline and before the call to kthread_stop(), which may lead to use after free.
Cc: Brendan Higgins brendanhiggins@google.com Cc: Shuah Khan skhan@linuxfoundation.org Reviewed-by: Kees Cook keescook@chromium.org Fixes: adf505457032 ("kunit: fix UAF when run kfence test case test_gfpzero") Reviewed-by: David Gow davidgow@google.com Reviewed-by: Rae Moar rmoar@google.com Signed-off-by: Mickaël Salaün mic@digikod.net Link: https://lore.kernel.org/r/20240408074625.65017-3-mic@digikod.net Signed-off-by: Shuah Khan skhan@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- lib/kunit/try-catch.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/lib/kunit/try-catch.c b/lib/kunit/try-catch.c index f7825991d576a..d9d1df28cc52e 100644 --- a/lib/kunit/try-catch.c +++ b/lib/kunit/try-catch.c @@ -11,6 +11,7 @@ #include <linux/completion.h> #include <linux/kernel.h> #include <linux/kthread.h> +#include <linux/sched/task.h>
#include "try-catch-impl.h"
@@ -65,13 +66,14 @@ void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context) try_catch->context = context; try_catch->try_completion = &try_completion; try_catch->try_result = 0; - task_struct = kthread_run(kunit_generic_run_threadfn_adapter, - try_catch, - "kunit_try_catch_thread"); + task_struct = kthread_create(kunit_generic_run_threadfn_adapter, + try_catch, "kunit_try_catch_thread"); if (IS_ERR(task_struct)) { try_catch->catch(try_catch->context); return; } + get_task_struct(task_struct); + wake_up_process(task_struct);
time_remaining = wait_for_completion_timeout(&try_completion, kunit_test_timeout()); @@ -81,6 +83,7 @@ void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context) kthread_stop(task_struct); }
+ put_task_struct(task_struct); exit_code = try_catch->try_result;
if (!exit_code)