| 文件 | 最后提交记录 | 最后更新时间 |
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livepatch: Use the default ftrace_ops instead of REGS when ARGS is available When CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS is available, the ftrace call will be able to set the ip of the calling function. This will improve the performance of live kernel patching where it does not need all the regs to be stored just to change the instruction pointer. If all archs that support live kernel patching also support HAVE_DYNAMIC_FTRACE_WITH_ARGS, then the architecture specific function klp_arch_set_pc() could be made generic. It is possible that an arch can support HAVE_DYNAMIC_FTRACE_WITH_ARGS but not HAVE_DYNAMIC_FTRACE_WITH_REGS and then have access to live patching. Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: live-patching@vger.kernel.org Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> | 5 年前 | |
livepatch: Basic API to track system state changes This is another step how to help maintaining more livepatches. One big help was the atomic replace and cumulative livepatches. These livepatches replace the already installed ones. Therefore it should be enough when each cumulative livepatch is consistent. The problems might come with shadow variables and callbacks. They might change the system behavior or state so that it is no longer safe to go back and use an older livepatch or the original kernel code. Also, a new livepatch must be able to detect changes which were made by the already installed livepatches. This is where the livepatch system state tracking gets useful. It allows to: - find whether a system state has already been modified by previous livepatches - store data needed to manipulate and restore the system state The information about the manipulated system states is stored in an array of struct klp_state. It can be searched by two new functions klp_get_state() and klp_get_prev_state(). The dependencies are going to be solved by a version field added later. The only important information is that it will be allowed to modify the same state by more non-cumulative livepatches. It is similar to allowing to modify the same function several times. The livepatch author is responsible for preventing incompatible changes. Link: http://lkml.kernel.org/r/20191030154313.13263-3-pmladek@suse.com To: Jiri Kosina <jikos@kernel.org> Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Cc: Nicolai Stange <nstange@suse.de> Cc: live-patching@vger.kernel.org Cc: linux-kernel@vger.kernel.org Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Petr Mladek <pmladek@suse.com> | 6 年前 | |
livepatch: Match old_sympos 0 and 1 in klp_find_func() [ Upstream commit 139560e8b973402140cafeb68c656c1374bd4c20 ] When there is only one function of the same name, old_sympos of 0 and 1 are logically identical. Match them in klp_find_func(). This is to avoid a corner case with different toolchain behavior. In this specific issue, two versions of kpatch-build were used to build livepatch for the same kernel. One assigns old_sympos == 0 for unique local functions, the other assigns old_sympos == 1 for unique local functions. Both versions work fine by themselves. (PS: This behavior change was introduced in a downstream version of kpatch-build. This change does not exist in upstream kpatch-build.) However, during livepatch upgrade (with the replace flag set) from a patch built with one version of kpatch-build to the same fix built with the other version of kpatch-build, livepatching fails with errors like: [ 14.218706] sysfs: cannot create duplicate filename 'xxx/somefunc,1' ... [ 14.219466] Call Trace: [ 14.219468] <TASK> [ 14.219469] dump_stack_lvl+0x47/0x60 [ 14.219474] sysfs_warn_dup.cold+0x17/0x27 [ 14.219476] sysfs_create_dir_ns+0x95/0xb0 [ 14.219479] kobject_add_internal+0x9e/0x260 [ 14.219483] kobject_add+0x68/0x80 [ 14.219485] ? kstrdup+0x3c/0xa0 [ 14.219486] klp_enable_patch+0x320/0x830 [ 14.219488] patch_init+0x443/0x1000 [ccc_0_6] [ 14.219491] ? 0xffffffffa05eb000 [ 14.219492] do_one_initcall+0x2e/0x190 [ 14.219494] do_init_module+0x67/0x270 [ 14.219496] init_module_from_file+0x75/0xa0 [ 14.219499] idempotent_init_module+0x15a/0x240 [ 14.219501] __x64_sys_finit_module+0x61/0xc0 [ 14.219503] do_syscall_64+0x5b/0x160 [ 14.219505] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 14.219507] RIP: 0033:0x7f545a4bd96d ... [ 14.219516] kobject: kobject_add_internal failed for somefunc,1 with -EEXIST, don't try to register things with the same name ... This happens because klp_find_func() thinks somefunc with old_sympos==0 is not the same as somefunc with old_sympos==1, and klp_add_object_nops adds another xxx/func,1 to the list of functions to patch. Signed-off-by: Song Liu <song@kernel.org> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> [pmladek@suse.com: Fixed some typos.] Reviewed-by: Petr Mladek <pmladek@suse.com> Tested-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org> (cherry picked from commit fefb29d64e7b2dd16feed60ca05676e525125ac6) Signed-off-by: Wentao Guan <guanwentao@uniontech.com> | 6 个月前 | |
livepatch: Keep replaced patches until post_patch callback is called Pre/post (un)patch callbacks might manipulate the system state. Cumulative livepatches might need to take over the changes made by the replaced ones. For this they might need to access some data stored or referenced by the old livepatches. Therefore the replaced livepatches have to stay around until post_patch() callback is called. It is achieved by calling the free functions later. It is the same location where disabled livepatches have already been freed. Link: http://lkml.kernel.org/r/20191030154313.13263-2-pmladek@suse.com To: Jiri Kosina <jikos@kernel.org> Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Cc: Nicolai Stange <nstange@suse.de> Cc: live-patching@vger.kernel.org Cc: linux-kernel@vger.kernel.org Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Petr Mladek <pmladek@suse.com> | 6 年前 | |
livepatch: Rename KLP_* to KLP_TRANSITION_* commit d927752f287fe10965612541593468ffcfa9231f upstream The original macros of KLP_* is about the state of the transition. Rename macros of KLP_* to KLP_TRANSITION_* to fix the confusing description of klp transition state. Signed-off-by: Wardenjohn <zhangwarden@gmail.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Tested-by: Petr Mladek <pmladek@suse.com> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Acked-by: Miroslav Benes <mbenes@suse.cz> Link: https://lore.kernel.org/r/20240507050111.38195-2-zhangwarden@gmail.com Signed-off-by: Petr Mladek <pmladek@suse.com> [ Backport from v6.9 ] Signed-off-by: zhangyongde.zyd <ydzhang@linux.alibaba.com> Signed-off-by: WangYuli <wangyuli@uniontech.com> | 11 个月前 | |
livepatch: Remove Nop structures when unused Replaced patches are removed from the stack when the transition is finished. It means that Nop structures will never be needed again and can be removed. Why should we care? + Nop structures give the impression that the function is patched even though the ftrace handler has no effect. + Ftrace handlers do not come for free. They cause slowdown that might be visible in some workloads. The ftrace-related slowdown might actually be the reason why the function is no longer patched in the new cumulative patch. One would expect that cumulative patch would help solve these problems as well. + Cumulative patches are supposed to replace any earlier version of the patch. The amount of NOPs depends on which version was replaced. This multiplies the amount of scenarios that might happen. One might say that NOPs are innocent. But there are even optimized NOP instructions for different processors, for example, see arch/x86/kernel/alternative.c. And klp_ftrace_handler() is much more complicated. + It sounds natural to clean up a mess that is no longer needed. It could only be worse if we do not do it. This patch allows to unpatch and free the dynamic structures independently when the transition finishes. The free part is a bit tricky because kobject free callbacks are called asynchronously. We could not wait for them easily. Fortunately, we do not have to. Any further access can be avoided by removing them from the dynamic lists. Signed-off-by: Petr Mladek <pmladek@suse.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> | 7 年前 | |
Documentation: livepatch: Add livepatch API page The livepatch subsystem has several exported functions and objects with kerneldoc comments. Though the livepatch documentation contains handwritten descriptions of all of these exported functions, they are currently not pulled into the docs build using the kernel-doc directive. In order to allow readers of the documentation to see the full kerneldoc comments in the generated documentation files, this change adds a new Documentation/livepatch/api.rst page which contains kernel-doc directives to link the kerneldoc comments directly in the documentation. With this, all of the hand-written descriptions of the APIs now cross-reference the kerneldoc comments on the new Livepatching APIs page, and running ./scripts/find-unused-docs.sh on kernel/livepatch no longer shows any files as missing documentation. Note that all of the handwritten API descriptions were left alone with the exception of Documentation/livepatch/system-state.rst, which was updated to allow the cross-referencing to work correctly. The file now follows the cross-referencing formatting guidance specified in Documentation/doc-guide/kernel-doc.rst. Furthermore, some comments around klp_shadow_free_all() were updated to say <_, id> rather than <*, id> to match the rest of the file, and to prevent the docs build from emitting an "Inline emphasis start-string without end string" error. Signed-off-by: David Vernet <void@manifault.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20211221145743.4098360-1-void@manifault.com | 4 年前 | |
kernel/: fix repeated words in comments Fix multiple occurrences of duplicated words in kernel/. Fix one typo/spello on the same line as a duplicate word. Change one instance of "the the" to "that the". Otherwise just drop one of the repeated words. Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/98202fa6-8919-ef63-9efe-c0fad5ca7af1@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> | 5 年前 | |
livepatch: Allow to distinguish different version of system state changes The atomic replace runs pre/post (un)install callbacks only from the new livepatch. There are several reasons for this: + Simplicity: clear ordering of operations, no interactions between old and new callbacks. + Reliability: only new livepatch knows what changes can already be made by older livepatches and how to take over the state. + Testing: the atomic replace can be properly tested only when a newer livepatch is available. It might be too late to fix unwanted effect of callbacks from older livepatches. It might happen that an older change is not enough and the same system state has to be modified another way. Different changes need to get distinguished by a version number added to struct klp_state. The version can also be used to prevent loading incompatible livepatches. The check is done when the livepatch is enabled. The rules are: + Any completely new system state modification is allowed. + System state modifications with the same or higher version are allowed for already modified system states. + Cumulative livepatches must handle all system state modifications from already installed livepatches. + Non-cumulative livepatches are allowed to touch already modified system states. Link: http://lkml.kernel.org/r/20191030154313.13263-4-pmladek@suse.com To: Jiri Kosina <jikos@kernel.org> Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Cc: Nicolai Stange <nstange@suse.de> Cc: live-patching@vger.kernel.org Cc: linux-kernel@vger.kernel.org Acked-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Joe Lawrence <joe.lawrence@redhat.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Petr Mladek <pmladek@suse.com> | 6 年前 | |
livepatch: Rename KLP_* to KLP_TRANSITION_* commit d927752f287fe10965612541593468ffcfa9231f upstream The original macros of KLP_* is about the state of the transition. Rename macros of KLP_* to KLP_TRANSITION_* to fix the confusing description of klp transition state. Signed-off-by: Wardenjohn <zhangwarden@gmail.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Tested-by: Petr Mladek <pmladek@suse.com> Acked-by: Josh Poimboeuf <jpoimboe@kernel.org> Acked-by: Miroslav Benes <mbenes@suse.cz> Link: https://lore.kernel.org/r/20240507050111.38195-2-zhangwarden@gmail.com Signed-off-by: Petr Mladek <pmladek@suse.com> [ Backport from v6.9 ] Signed-off-by: zhangyongde.zyd <ydzhang@linux.alibaba.com> Signed-off-by: WangYuli <wangyuli@uniontech.com> | 11 个月前 | |
livepatch: Remove signal sysfs attribute The fake signal is send automatically now. We can rely on it completely and remove the sysfs attribute. Signed-off-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz> | 7 年前 |