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Commit b658ffa2 authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

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
parent 22e05fb5

llkd/README.md

+3 −2
Original line number Diff line number Diff line
@@ -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

+2 −1
Original line number Diff line number Diff line
@@ -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]"