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author | Masami Hiramatsu <mhiramat@redhat.com> | 2009-04-06 19:01:02 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-04-07 08:31:08 -0700 |
commit | de5bd88d5a5cce3cacea904d3503e5ebdb3852a2 (patch) | |
tree | da24ac8b38d371ee03a21ed0f3647c518689ebd3 /Documentation/kprobes.txt | |
parent | e579abeb58eb4b8d7321c6eb44dd9e2d0cbaebaa (diff) | |
download | linux-de5bd88d5a5cce3cacea904d3503e5ebdb3852a2.tar.bz2 |
kprobes: support per-kprobe disabling
Add disable_kprobe() and enable_kprobe() to disable/enable kprobes
temporarily.
disable_kprobe() asynchronously disables probe handlers of specified
kprobe. So, after calling it, some handlers can be called at a while.
enable_kprobe() enables specified kprobe.
aggr_pre_handler and aggr_post_handler check disabled probes. On the
other hand aggr_break_handler and aggr_fault_handler don't check it
because these handlers will be called while executing pre or post handlers
and usually those help error handling.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/kprobes.txt')
-rw-r--r-- | Documentation/kprobes.txt | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/Documentation/kprobes.txt b/Documentation/kprobes.txt index 48b3de90eb1e..f609af242d6c 100644 --- a/Documentation/kprobes.txt +++ b/Documentation/kprobes.txt @@ -212,7 +212,9 @@ hit, Kprobes calls kp->pre_handler. After the probed instruction is single-stepped, Kprobe calls kp->post_handler. If a fault occurs during execution of kp->pre_handler or kp->post_handler, or during single-stepping of the probed instruction, Kprobes calls -kp->fault_handler. Any or all handlers can be NULL. +kp->fault_handler. Any or all handlers can be NULL. If kp->flags +is set KPROBE_FLAG_DISABLED, that kp will be registered but disabled, +so, it's handlers aren't hit until calling enable_kprobe(kp). NOTE: 1. With the introduction of the "symbol_name" field to struct kprobe, @@ -363,6 +365,22 @@ probes) in the specified array, they clear the addr field of those incorrect probes. However, other probes in the array are unregistered correctly. +4.7 disable_kprobe + +#include <linux/kprobes.h> +int disable_kprobe(struct kprobe *kp); + +Temporarily disables the specified kprobe. You can enable it again by using +enable_kprobe(). You must specify the kprobe which has been registered. + +4.8 enable_kprobe + +#include <linux/kprobes.h> +int enable_kprobe(struct kprobe *kp); + +Enables kprobe which has been disabled by disable_kprobe(). You must specify +the kprobe which has been registered. + 5. Kprobes Features and Limitations Kprobes allows multiple probes at the same address. Currently, @@ -500,10 +518,14 @@ the probe. If the probed function belongs to a module, the module name is also specified. Following columns show probe status. If the probe is on a virtual address that is no longer valid (module init sections, module virtual addresses that correspond to modules that've been unloaded), -such probes are marked with [GONE]. +such probes are marked with [GONE]. If the probe is temporarily disabled, +such probes are marked with [DISABLED]. -/debug/kprobes/enabled: Turn kprobes ON/OFF +/debug/kprobes/enabled: Turn kprobes ON/OFF forcibly. -Provides a knob to globally turn registered kprobes ON or OFF. By default, -all kprobes are enabled. By echoing "0" to this file, all registered probes -will be disarmed, till such time a "1" is echoed to this file. +Provides a knob to globally and forcibly turn registered kprobes ON or OFF. +By default, all kprobes are enabled. By echoing "0" to this file, all +registered probes will be disarmed, till such time a "1" is echoed to this +file. Note that this knob just disarms and arms all kprobes and doesn't +change each probe's disabling state. This means that disabled kprobes (marked +[DISABLED]) will be not enabled if you turn ON all kprobes by this knob. |