diff options
| author | Miroslav Benes <mbenes@suse.cz> | 2017-11-22 11:29:21 +0100 |
|---|---|---|
| committer | Jiri Kosina <jkosina@suse.cz> | 2017-12-07 13:21:35 +0100 |
| commit | c99a2be790b07752d8cc694434d3450afd4c5a00 (patch) | |
| tree | 086f38cd5bae5145e4677c552a8776990f12c2fb /Documentation/ABI/testing/sysfs-kernel-livepatch | |
| parent | 43347d56c8d9dd732cee2f8efd384ad21dd1f6c4 (diff) | |
livepatch: force transition to finish
If a task sleeps in a set of patched functions uninterruptedly, it could
block the whole transition indefinitely. Thus it may be useful to clear
its TIF_PATCH_PENDING to allow the process to finish.
Admin can do that now by writing to force sysfs attribute in livepatch
sysfs directory. TIF_PATCH_PENDING is then cleared for all tasks and the
transition can finish successfully.
Important note! Administrator should not use this feature without a
clearance from a patch distributor. It must be checked that by doing so
the consistency model guarantees are not violated. Removal (rmmod) of
patch modules is permanently disabled when the feature is used. It
cannot be guaranteed there is no task sleeping in such module.
Signed-off-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-kernel-livepatch')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-kernel-livepatch | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-kernel-livepatch b/Documentation/ABI/testing/sysfs-kernel-livepatch index 3bb9d5bc1ce3..dac7e1e62a8b 100644 --- a/Documentation/ABI/testing/sysfs-kernel-livepatch +++ b/Documentation/ABI/testing/sysfs-kernel-livepatch @@ -45,6 +45,20 @@ Description: signal pending structures). Tasks are interrupted or woken up, and forced to change their patched state. +What: /sys/kernel/livepatch/<patch>/force +Date: Nov 2017 +KernelVersion: 4.15.0 +Contact: live-patching@vger.kernel.org +Description: + A writable attribute that allows administrator to affect the + course of an existing transition. Writing 1 clears + TIF_PATCH_PENDING flag of all tasks and thus forces the tasks to + the patched or unpatched state. Administrator should not + use this feature without a clearance from a patch + distributor. Removal (rmmod) of patch modules is permanently + disabled when the feature is used. See + Documentation/livepatch/livepatch.txt for more information. + What: /sys/kernel/livepatch/<patch>/<object> Date: Nov 2014 KernelVersion: 3.19.0 |