kasan: handle concurrent kasan_record_aux_stack calls

kasan: handle concurrent kasan_record_aux_stack calls

kasan_record_aux_stack can be called concurrently on the same object.
This might lead to a race condition when rotating the saved aux stack
trace handles, which in turns leads to incorrect accounting of stack depot
handles and refcount underflows in the stack depot code.

Fix by introducing a raw spinlock to protect the aux stack trace handles
in kasan_record_aux_stack.

Link: https://lkml.kernel.org/r/1606b960e2f746862d1f459515972f9695bf448a.1703020707.git.andreyknvl@google.com
Fixes: 773688a6cb24 ("kasan: use stack_depot_put for Generic mode")
Signed-off-by: Andrey Konovalov <[email protected]>
Reported-by: Tetsuo Handa <[email protected]>
Reported-by: [email protected]
Closes: https://lore.kernel.org/all/[email protected]/
Reviewed-by: Marco Elver <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Evgenii Stepanov <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>