diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/keys.txt | 39 | ||||
| -rw-r--r-- | Documentation/kmemleak.txt | 31 |
2 files changed, 69 insertions, 1 deletions
diff --git a/Documentation/keys.txt b/Documentation/keys.txt index b56aacc1fff..e4dbbdb1bd9 100644 --- a/Documentation/keys.txt +++ b/Documentation/keys.txt @@ -26,7 +26,7 @@ This document has the following sections: - Notes on accessing payload contents - Defining a key type - Request-key callback service - - Key access filesystem + - Garbage collection ============ @@ -113,6 +113,9 @@ Each key has a number of attributes: (*) Dead. The key's type was unregistered, and so the key is now useless. +Keys in the last three states are subject to garbage collection. See the +section on "Garbage collection". + ==================== KEY SERVICE OVERVIEW @@ -754,6 +757,26 @@ The keyctl syscall functions are: successful. + (*) Install the calling process's session keyring on its parent. + + long keyctl(KEYCTL_SESSION_TO_PARENT); + + This functions attempts to install the calling process's session keyring + on to the calling process's parent, replacing the parent's current session + keyring. + + The calling process must have the same ownership as its parent, the + keyring must have the same ownership as the calling process, the calling + process must have LINK permission on the keyring and the active LSM module + mustn't deny permission, otherwise error EPERM will be returned. + + Error ENOMEM will be returned if there was insufficient memory to complete + the operation, otherwise 0 will be returned to indicate success. + + The keyring will be replaced next time the parent process leaves the + kernel and resumes executing userspace. + + =============== KERNEL SERVICES =============== @@ -1231,3 +1254,17 @@ by executing: In this case, the program isn't required to actually attach the key to a ring; the rings are provided for reference. + + +================== +GARBAGE COLLECTION +================== + +Dead keys (for which the type has been removed) will be automatically unlinked +from those keyrings that point to them and deleted as soon as possible by a +background garbage collector. + +Similarly, revoked and expired keys will be garbage collected, but only after a +certain amount of time has passed. This time is set as a number of seconds in: + + /proc/sys/kernel/keys/gc_delay diff --git a/Documentation/kmemleak.txt b/Documentation/kmemleak.txt index 89068030b01..34f6638aa5a 100644 --- a/Documentation/kmemleak.txt +++ b/Documentation/kmemleak.txt @@ -27,6 +27,13 @@ To trigger an intermediate memory scan: # echo scan > /sys/kernel/debug/kmemleak +To clear the list of all current possible memory leaks: + + # echo clear > /sys/kernel/debug/kmemleak + +New leaks will then come up upon reading /sys/kernel/debug/kmemleak +again. + Note that the orphan objects are listed in the order they were allocated and one object at the beginning of the list may cause other subsequent objects to be reported as orphan. @@ -42,6 +49,9 @@ Memory scanning parameters can be modified at run-time by writing to the scan=<secs> - set the automatic memory scanning period in seconds (default 600, 0 to stop the automatic scanning) scan - trigger a memory scan + clear - clear list of current memory leak suspects, done by + marking all current reported unreferenced objects grey + dump=<addr> - dump information about the object found at <addr> Kmemleak can also be disabled at boot-time by passing "kmemleak=off" on the kernel command line. @@ -86,6 +96,27 @@ avoid this, kmemleak can also store the number of values pointing to an address inside the block address range that need to be found so that the block is not considered a leak. One example is __vmalloc(). +Testing specific sections with kmemleak +--------------------------------------- + +Upon initial bootup your /sys/kernel/debug/kmemleak output page may be +quite extensive. This can also be the case if you have very buggy code +when doing development. To work around these situations you can use the +'clear' command to clear all reported unreferenced objects from the +/sys/kernel/debug/kmemleak output. By issuing a 'scan' after a 'clear' +you can find new unreferenced objects; this should help with testing +specific sections of code. + +To test a critical section on demand with a clean kmemleak do: + + # echo clear > /sys/kernel/debug/kmemleak + ... test your kernel or modules ... + # echo scan > /sys/kernel/debug/kmemleak + +Then as usual to get your report with: + + # cat /sys/kernel/debug/kmemleak + Kmemleak API ------------ |