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lockdep: Allow tuning tracing capacity constants.

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Since syzkaller continues various test cases until the kernel crashes,
syzkaller tends to examine more locking dependencies than normal systems.
As a result, syzbot is reporting that the fuzz testing was terminated
due to hitting upper limits lockdep can track [1] [2] [3]. Since analysis
via /proc/lockdep* did not show any obvious culprit [4] [5], we have no
choice but allow tuning tracing capacity constants.

[1] https://syzkaller.appspot.com/bug?id=3d97ba93fb3566000c1c59691ea427370d33ea1b
[2] https://syzkaller.appspot.com/bug?id=381cb436fe60dc03d7fd2a092b46d7f09542a72a
[3] https://syzkaller.appspot.com/bug?id=a588183ac34c1437fc0785e8f220e88282e5a29f
[4] https://lkml.kernel.org/r/4b8f7a57-fa20-47bd-48a0-ae35d860f233@i-love.sakura.ne.jp
[5] https://lkml.kernel.org/r/1c351187-253b-2d49-acaf-4563c63ae7d2@i-love.sakura.ne.jp

References: https://lkml.kernel.org/r/1595640639-9310-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
This commit is contained in:
Tetsuo Handa
2021-04-05 20:33:57 +09:00
parent e49d033bdd
commit 5dc33592e9
3 changed files with 45 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/locking/lockdep.c
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@@ -1392,7 +1392,7 @@ static int add_lock_to_list(struct lock_class *this,
/*
* For good efficiency of modular, we use power of 2
*/
#define MAX_CIRCULAR_QUEUE_SIZE 4096UL
#define MAX_CIRCULAR_QUEUE_SIZE (1UL << CONFIG_LOCKDEP_CIRCULAR_QUEUE_BITS)
#define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1)
/*

8
kernel/locking/lockdep_internals.h
View File

@@ -99,16 +99,16 @@ static const unsigned long LOCKF_USED_IN_IRQ_READ =
#define MAX_STACK_TRACE_ENTRIES 262144UL
#define STACK_TRACE_HASH_SIZE 8192
#else
#define MAX_LOCKDEP_ENTRIES 32768UL
#define MAX_LOCKDEP_ENTRIES (1UL << CONFIG_LOCKDEP_BITS)
#define MAX_LOCKDEP_CHAINS_BITS 16
#define MAX_LOCKDEP_CHAINS_BITS CONFIG_LOCKDEP_CHAINS_BITS
/*
* Stack-trace: tightly packed array of stack backtrace
* addresses. Protected by the hash_lock.
*/
#define MAX_STACK_TRACE_ENTRIES 524288UL
#define STACK_TRACE_HASH_SIZE 16384
#define MAX_STACK_TRACE_ENTRIES (1UL << CONFIG_LOCKDEP_STACK_TRACE_BITS)
#define STACK_TRACE_HASH_SIZE (1 << CONFIG_LOCKDEP_STACK_TRACE_HASH_BITS)
#endif
/*