user/sven/linux.git/kernel/livepatch, branch v5.10.249

livepatch: Match old_sympos 0 and 1 in klp_find_func()

2026-01-19T12:11:41Z

[ 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] [ 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 Acked-by: Josh Poimboeuf [pmladek@suse.com: Fixed some typos.] Reviewed-by: Petr Mladek Tested-by: Petr Mladek Signed-off-by: Petr Mladek Signed-off-by: Sasha Levin

kallsyms: refactor {,module_}kallsyms_on_each_symbol

2024-06-21T12:52:58Z

[ Upstream commit 013c1667cf78c1d847152f7116436d82dcab3db4 ] Require an explicit call to module_kallsyms_on_each_symbol to look for symbols in modules instead of the call from kallsyms_on_each_symbol, and acquire module_mutex inside of module_kallsyms_on_each_symbol instead of leaving that up to the caller. Note that this slightly changes the behavior for the livepatch code in that the symbols from vmlinux are not iterated anymore if objname is set, but that actually is the desired behavior in this case. Reviewed-by: Petr Mladek Acked-by: Miroslav Benes Signed-off-by: Christoph Hellwig Signed-off-by: Jessica Yu Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

module: use RCU to synchronize find_module

2024-06-21T12:52:58Z

[ Upstream commit a006050575745ca2be25118b90f1c37f454ac542 ] Allow for a RCU-sched critical section around find_module, following the lower level find_module_all helper, and switch the two callers outside of module.c to use such a RCU-sched critical section instead of module_mutex. Reviewed-by: Petr Mladek Acked-by: Miroslav Benes Signed-off-by: Christoph Hellwig Signed-off-by: Jessica Yu Signed-off-by: Chuck Lever Signed-off-by: Sasha Levin

livepatch: Fix missing newline character in klp_resolve_symbols()

2023-11-20T10:06:52Z

[ Upstream commit 67e18e132f0fd738f8c8cac3aa1420312073f795 ] Without the newline character, the log may not be printed immediately after the error occurs. Fixes: ca376a937486 ("livepatch: Prevent module-specific KLP rela sections from referencing vmlinux symbols") Signed-off-by: Zheng Yejian Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20230914072644.4098857-1-zhengyejian1@huawei.com Signed-off-by: Sasha Levin

livepatch: fix race between fork and KLP transition

2022-10-26T11:25:14Z

commit 747f7a2901174c9afa805dddfb7b24db6f65e985 upstream. The KLP transition code depends on the TIF_PATCH_PENDING and the task->patch_state to stay in sync. On a normal (forward) transition, TIF_PATCH_PENDING will be set on every task in the system, while on a reverse transition (after a failed forward one) first TIF_PATCH_PENDING will be cleared from every task, followed by it being set on tasks that need to be transitioned back to the original code. However, the fork code copies over the TIF_PATCH_PENDING flag from the parent to the child early on, in dup_task_struct and setup_thread_stack. Much later, klp_copy_process will set child->patch_state to match that of the parent. However, the parent's patch_state may have been changed by KLP loading or unloading since it was initially copied over into the child. This results in the KLP code occasionally hitting this warning in klp_complete_transition: for_each_process_thread(g, task) { WARN_ON_ONCE(test_tsk_thread_flag(task, TIF_PATCH_PENDING)); task->patch_state = KLP_UNDEFINED; } Set, or clear, the TIF_PATCH_PENDING flag in the child task depending on whether or not it is needed at the time klp_copy_process is called, at a point in copy_process where the tasklist_lock is held exclusively, preventing races with the KLP code. The KLP code does have a few places where the state is changed without the tasklist_lock held, but those should not cause problems because klp_update_patch_state(current) cannot be called while the current task is in the middle of fork, klp_check_and_switch_task() which is called under the pi_lock, which prevents rescheduling, and manipulation of the patch state of idle tasks, which do not fork. This should prevent this warning from triggering again in the future, and close the race for both normal and reverse transitions. Signed-off-by: Rik van Riel Reported-by: Breno Leitao Reviewed-by: Petr Mladek Acked-by: Josh Poimboeuf Fixes: d83a7cb375ee ("livepatch: change to a per-task consistency model") Cc: stable@kernel.org Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20220808150019.03d6a67b@imladris.surriel.com Signed-off-by: Greg Kroah-Hartman

livepatch: Fix build failure on 32 bits processors

2022-04-08T12:40:15Z

[ Upstream commit 2f293651eca3eacaeb56747dede31edace7329d2 ] Trying to build livepatch on powerpc/32 results in: kernel/livepatch/core.c: In function 'klp_resolve_symbols': kernel/livepatch/core.c:221:23: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast] 221 | sym = (Elf64_Sym *)sechdrs[symndx].sh_addr + ELF_R_SYM(relas[i].r_info); | ^ kernel/livepatch/core.c:221:21: error: assignment to 'Elf32_Sym *' {aka 'struct elf32_sym *'} from incompatible pointer type 'Elf64_Sym *' {aka 'struct elf64_sym *'} [-Werror=incompatible-pointer-types] 221 | sym = (Elf64_Sym *)sechdrs[symndx].sh_addr + ELF_R_SYM(relas[i].r_info); | ^ kernel/livepatch/core.c: In function 'klp_apply_section_relocs': kernel/livepatch/core.c:312:35: error: passing argument 1 of 'klp_resolve_symbols' from incompatible pointer type [-Werror=incompatible-pointer-types] 312 | ret = klp_resolve_symbols(sechdrs, strtab, symndx, sec, sec_objname); | ^~~~~~~ | | | Elf32_Shdr * {aka struct elf32_shdr *} kernel/livepatch/core.c:193:44: note: expected 'Elf64_Shdr *' {aka 'struct elf64_shdr *'} but argument is of type 'Elf32_Shdr *' {aka 'struct elf32_shdr *'} 193 | static int klp_resolve_symbols(Elf64_Shdr *sechdrs, const char *strtab, | ~~~~~~~~~~~~^~~~~~~ Fix it by using the right types instead of forcing 64 bits types. Fixes: 7c8e2bdd5f0d ("livepatch: Apply vmlinux-specific KLP relocations early") Signed-off-by: Christophe Leroy Acked-by: Petr Mladek Acked-by: Joe Lawrence Acked-by: Miroslav Benes Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/5288e11b018a762ea3351cc8fb2d4f15093a4457.1640017960.git.christophe.leroy@csgroup.eu Signed-off-by: Sasha Levin

kernel/: fix repeated words in comments

2020-10-16T18:11:19Z

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 Signed-off-by: Andrew Morton Link: https://lkml.kernel.org/r/98202fa6-8919-ef63-9efe-c0fad5ca7af1@infradead.org Signed-off-by: Linus Torvalds

livepatch: Make klp_apply_object_relocs static

2020-05-10T22:31:38Z

Fix the following sparse warning: kernel/livepatch/core.c:748:5: warning: symbol 'klp_apply_object_relocs' was not declared. The klp_apply_object_relocs() has only one call site within core.c; it should be static Fixes: 7c8e2bdd5f0d ("livepatch: Apply vmlinux-specific KLP relocations early") Reported-by: Hulk Robot Signed-off-by: Samuel Zou Acked-by: Josh Poimboeuf Signed-off-by: Jiri Kosina

x86/module: Use text_mutex in apply_relocate_add()

2020-05-07T22:12:43Z

Now that the livepatch code no longer needs the text_mutex for changing module permissions, move its usage down to apply_relocate_add(). Note the s390 version of apply_relocate_add() doesn't need to use the text_mutex because it already uses s390_kernel_write_lock, which accomplishes the same task. Signed-off-by: Josh Poimboeuf Acked-by: Joe Lawrence Acked-by: Miroslav Benes Signed-off-by: Jiri Kosina

livepatch: Remove module_disable_ro() usage

2020-05-07T22:12:43Z

With arch_klp_init_object_loaded() gone, and apply_relocate_add() now using text_poke(), livepatch no longer needs to use module_disable_ro(). Signed-off-by: Josh Poimboeuf Acked-by: Peter Zijlstra (Intel) Acked-by: Joe Lawrence Acked-by: Miroslav Benes Signed-off-by: Jiri Kosina