llkd: check stack for wait_on_page_bit_killable

User process in S state blocked by deadlock in I/O system

wait_on_page_bit is covered by regular D state tracking.

Bug: 120776455
Test: long term stability on multiple devices
Change-Id: Icdb99b8095f384cb440f0f2bdeba86c5991b9ef4

llkd/README.md

@@ -135,8 +135,9 @@ Only active on userdebug or eng builds.
 default 2 minutes samples of threads for D or Z.
 
 #### ro.llk.stack
-default cma_alloc,__get_user_pages,bit_wait_io comma separated list of kernel
-symbols.  The string "*false*" is the equivalent to an *empty* list.
+default cma_alloc,__get_user_pages,bit_wait_io,wait_on_page_bit_killable
+comma separated list of kernel symbols.
+The string "*false*" is the equivalent to an *empty* list.
 Look for kernel stack symbols that if ever persistently present can
 indicate a subsystem is locked up.
 Beware, check does not on purpose do forward scheduling ABA except by polling

llkd/include/llkd.h

@@ -50,7 +50,8 @@ unsigned llkCheckMilliseconds(void);
 /* LLK_CHECK_MS_DEFAULT = actual timeout_ms / LLK_CHECKS_PER_TIMEOUT_DEFAULT */
 #define LLK_CHECKS_PER_TIMEOUT_DEFAULT 5
 #define LLK_CHECK_STACK_PROPERTY       "ro.llk.stack"
-#define LLK_CHECK_STACK_DEFAULT        "cma_alloc,__get_user_pages,bit_wait_io"
+#define LLK_CHECK_STACK_DEFAULT        \
+    "cma_alloc,__get_user_pages,bit_wait_io,wait_on_page_bit_killable"
 #define LLK_BLACKLIST_PROCESS_PROPERTY "ro.llk.blacklist.process"
 #define LLK_BLACKLIST_PROCESS_DEFAULT  \
     "0,1,2,init,[kthreadd],[khungtaskd],lmkd,llkd,watchdogd,[watchdogd],[watchdogd/0]"