From a9d9058abab4ac17b79d500506e6c74bd16cecdc Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Thu, 25 Jun 2009 10:16:11 +0100 Subject: [PATCH] kmemleak: Allow the early log buffer to be configurable. (feature suggested by Sergey Senozhatsky) Kmemleak needs to track all the memory allocations but some of these happen before kmemleak is initialised. These are stored in an internal buffer which may be exceeded in some kernel configurations. This patch adds a configuration option with a default value of 400 and also removes the stack dump when the early log buffer is exceeded. Signed-off-by: Catalin Marinas Acked-by: Sergey Senozhatsky --- Documentation/kmemleak.txt | 4 ++++ lib/Kconfig.debug | 12 ++++++++++++ mm/kmemleak.c | 5 +++-- 3 files changed, 19 insertions(+), 2 deletions(-) diff --git a/Documentation/kmemleak.txt b/Documentation/kmemleak.txt index 0112da3..f655308 100644 --- a/Documentation/kmemleak.txt +++ b/Documentation/kmemleak.txt @@ -41,6 +41,10 @@ Memory scanning parameters can be modified at run-time by writing to the Kmemleak can also be disabled at boot-time by passing "kmemleak=off" on the kernel command line. +Memory may be allocated or freed before kmemleak is initialised and +these actions are stored in an early log buffer. The size of this buffer +is configured via the CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE option. + Basic Algorithm --------------- diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 4c32b1a..12327b2 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -359,6 +359,18 @@ config DEBUG_KMEMLEAK In order to access the kmemleak file, debugfs needs to be mounted (usually at /sys/kernel/debug). +config DEBUG_KMEMLEAK_EARLY_LOG_SIZE + int "Maximum kmemleak early log entries" + depends on DEBUG_KMEMLEAK + range 200 2000 + default 400 + help + Kmemleak must track all the memory allocations to avoid + reporting false positives. Since memory may be allocated or + freed before kmemleak is initialised, an early log buffer is + used to store these actions. If kmemleak reports "early log + buffer exceeded", please increase this value. + config DEBUG_KMEMLEAK_TEST tristate "Simple test for the kernel memory leak detector" depends on DEBUG_KMEMLEAK diff --git a/mm/kmemleak.c b/mm/kmemleak.c index c96f2c8..17096d1 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -235,7 +235,7 @@ struct early_log { }; /* early logging buffer and current position */ -static struct early_log early_log[200]; +static struct early_log early_log[CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE]; static int crt_early_log; static void kmemleak_disable(void); @@ -696,7 +696,8 @@ static void log_early(int op_type, const void *ptr, size_t size, struct early_log *log; if (crt_early_log >= ARRAY_SIZE(early_log)) { - kmemleak_stop("Early log buffer exceeded\n"); + pr_warning("Early log buffer exceeded\n"); + kmemleak_disable(); return; } -- 2.7.4