laptop-kernel/kernel/reboot.c, branch master

Merge branch 'for-7.3-hotfix' into for-linus

2026-10-16T15:38:25Z

nbcon/reboot: Switch NBCON consoles into the emergency mode in emergency_restart()

2026-10-14T09:39:03Z

When the system is going down a normal way, the NBCON kthreads are flushed and stopped properly via a syscore shutdown callback, see printk_kthreads_shutdown(). One missing piece is emergency_restart() where the kthreads are not stopped. It might be called from several non-panic code paths, e.g. sysrq-o, kdb_reboot(), or some watchdogs. Fix it by explicitly entering the emergency (atomic) mode and trying to flush the consoles there. Note that printk_trigger_flush() must be used instead of pr_flush() because the later is not safe in an atomic context. Reported-by: kernel test robot Closes: https://lore.kernel.org/all/202608061008.48a1e76e-lkp@intel.com/ Suggested-by: John Ogness Reviewed-by: John Ogness Link: https://patch.msgid.link/20261013154141.94016-1-pmladek@suse.com Signed-off-by: Petr Mladek

reboot: fix cad_pid use-after-free race

2026-08-31T08:25:46Z

cad_pid is a single kernel-wide struct pid pointer. proc_do_cad_pid() reads it and passes it to pid_vnr() without protecting the lifetime of the referenced struct pid. A concurrent writer can replace cad_pid and drop the final reference to the old struct pid after the reader has loaded the pointer but before pid_vnr() has finished dereferencing it, causing a use-after-free. kill_cad_pid() has the same lifetime race when it passes cad_pid to kill_pid(). At the time this issue was reported, an unprivileged user could reach the sysctl through user and PID namespaces because cad_pid was registered in pid_table[]. Moving cad_pid back to the global reboot sysctl table corrected that namespace and permission mismatch, but did not fix the underlying lifetime race. Fix this by treating cad_pid as an RCU-protected pointer at both read sites and by waiting for a grace period before dropping the old reference on the write side. call_rcu(&old_pid->rcu, ...) cannot be used here because free_pid() also queues pid->rcu; queueing the same rcu_head twice can corrupt the RCU callback list. Original KASAN crash stack: kernel/pid.c:545 pid_nr_ns() # reads freed pid->level kernel/pid.c:556 pid_vnr() # calls pid_nr_ns() kernel/pid.c:775 proc_do_cad_pid() # calls pid_vnr(cad_pid) Fixes: 9ec52099e4b8 ("[PATCH] replace cad_pid by a struct pid") Reported-by: AutonomousCodeSecurity@microsoft.com Closes: https://lore.kernel.org/all/20260717210143.4734-1-blbllhy@gmail.com/ Link: https://lore.kernel.org/all/alz5ZYLE4kaq_v2P@redhat.com/ Link: https://lore.kernel.org/all/al4ICz9biJKtdZc4@redhat.com/ Suggested-by: Mateusz Guzik Suggested-by: Bradley Morgan Suggested-by: Oleg Nesterov Suggested-by: Eric W. Biederman Suggested-by: Pavel Tikhomirov Cc: stable@vger.kernel.org Signed-off-by: Cen Zhang (Microsoft) Link: https://patch.msgid.link/20260814040944.16561-1-blbllhy@gmail.com Reviewed-by: Bradley Morgan Reviewed-by: Oleg Nesterov Reviewed-by: Pavel Tikhomirov Signed-off-by: Christian Brauner (Amutable)

sysctl: move the "cad_pid" entry from pid_table[] to kern_reboot_table[]

2026-08-05T13:28:23Z

cad_pid is global, and kill_cad_pid() is only used in the root namespace. However, due to pid_table_root_permissions(), a non-root user can unshare pid/user namespaces and modify it from the child namespace. This makes no sense and is simply wrong. Move it to kern_reboot_table[] where it logically belongs; this ensures that only GLOBAL_ROOT_UID can read/modify this sysctl. Note that this patch doesn't preserve "#ifdef CONFIG_PROC_SYSCTL" around the "cad_pid"; CONFIG_PROC_SYSCTL selects CONFIG_SYSCTL, so it is always set when kern_reboot_table[] is compiled. Cc: stable@vger.kernel.org Fixes: e054bcbe7e7a ("sysctl: move cad_pid into kernel/pid.c") Signed-off-by: Oleg Nesterov Acked-by: Alexey Gladkov Reviewed-by: Bradley Morgan Reviewed-by: Pavel Tikhomirov Signed-off-by: Joel Granados

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28Z

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

Merge tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-04-01T17:06:52Z

Pull non-MM updates from Andrew Morton: - The series "powerpc/crash: use generic crashkernel reservation" from Sourabh Jain changes powerpc's kexec code to use more of the generic layers. - The series "get_maintainer: report subsystem status separately" from Vlastimil Babka makes some long-requested improvements to the get_maintainer output. - The series "ucount: Simplify refcounting with rcuref_t" from Sebastian Siewior cleans up and optimizing the refcounting in the ucount code. - The series "reboot: support runtime configuration of emergency hw_protection action" from Ahmad Fatoum improves the ability for a driver to perform an emergency system shutdown or reboot. - The series "Converge on using secs_to_jiffies() part two" from Easwar Hariharan performs further migrations from msecs_to_jiffies() to secs_to_jiffies(). - The series "lib/interval_tree: add some test cases and cleanup" from Wei Yang permits more userspace testing of kernel library code, adds some more tests and performs some cleanups. - The series "hung_task: Dump the blocking task stacktrace" from Masami Hiramatsu arranges for the hung_task detector to dump the stack of the blocking task and not just that of the blocked task. - The series "resource: Split and use DEFINE_RES*() macros" from Andy Shevchenko provides some cleanups to the resource definition macros. - Plus the usual shower of singleton patches - please see the individual changelogs for details. * tag 'mm-nonmm-stable-2025-03-30-18-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (77 commits) mailmap: consolidate email addresses of Alexander Sverdlin fs/procfs: fix the comment above proc_pid_wchan() relay: use kasprintf() instead of fixed buffer formatting resource: replace open coded variant of DEFINE_RES() resource: replace open coded variants of DEFINE_RES_*_NAMED() resource: replace open coded variant of DEFINE_RES_NAMED_DESC() resource: split DEFINE_RES_NAMED_DESC() out of DEFINE_RES_NAMED() samples: add hung_task detector mutex blocking sample hung_task: show the blocker task if the task is hung on mutex kexec_core: accept unaccepted kexec segments' destination addresses watchdog/perf: optimize bytes copied and remove manual NUL-termination lib/interval_tree: fix the comment of interval_tree_span_iter_next_gap() lib/interval_tree: skip the check before go to the right subtree lib/interval_tree: add test case for span iteration lib/interval_tree: add test case for interval_tree_iter_xxx() helpers lib/rbtree: add random seed lib/rbtree: split tests lib/rbtree: enable userland test suite for rbtree related data structure checkpatch: describe --min-conf-desc-length scripts/gdb/symbols: determine KASLR offset on s390 ...

reboot: add support for configuring emergency hardware protection action

2025-03-17T06:24:14Z

We currently leave the decision of whether to shutdown or reboot to protect hardware in an emergency situation to the individual drivers. This works out in some cases, where the driver detecting the critical failure has inside knowledge: It binds to the system management controller for example or is guided by hardware description that defines what to do. In the general case, however, the driver detecting the issue can't know what the appropriate course of action is and shouldn't be dictating the policy of dealing with it. Therefore, add a global hw_protection toggle that allows the user to specify whether shutdown or reboot should be the default action when the driver doesn't set policy. This introduces no functional change yet as hw_protection_trigger() has no callers, but these will be added in subsequent commits. [arnd@arndb.de: hide unused hw_protection_attr] Link: https://lkml.kernel.org/r/20250224141849.1546019-1-arnd@kernel.org Link: https://lkml.kernel.org/r/20250217-hw_protection-reboot-v3-7-e1c09b090c0c@pengutronix.de Signed-off-by: Ahmad Fatoum Reviewed-by: Tzung-Bi Shih Cc: Benson Leung Cc: Daniel Lezcano Cc: Fabio Estevam Cc: Guenter Roeck Cc: Jonathan Corbet Cc: Liam Girdwood Cc: Lukasz Luba Cc: Mark Brown Cc: Matteo Croce Cc: Matti Vaittinen Cc: "Rafael J. Wysocki" Cc: Rob Herring (Arm) Cc: Rui Zhang Cc: Sascha Hauer Cc: "Serge E. Hallyn" Signed-off-by: Andrew Morton

reboot: indicate whether it is a HARDWARE PROTECTION reboot or shutdown

2025-03-17T06:24:13Z

It currently depends on the caller, whether we attempt a hardware protection shutdown (poweroff) or a reboot. A follow-up commit will make this partially user-configurable, so it's a good idea to have the emergency message clearly state whether the kernel is going for a reboot or a shutdown. Link: https://lkml.kernel.org/r/20250217-hw_protection-reboot-v3-6-e1c09b090c0c@pengutronix.de Signed-off-by: Ahmad Fatoum Reviewed-by: Tzung-Bi Shih Cc: Benson Leung Cc: Daniel Lezcano Cc: Fabio Estevam Cc: Guenter Roeck Cc: Jonathan Corbet Cc: Liam Girdwood Cc: Lukasz Luba Cc: Mark Brown Cc: Matteo Croce Cc: Matti Vaittinen Cc: "Rafael J. Wysocki" Cc: Rob Herring (Arm) Cc: Rui Zhang Cc: Sascha Hauer Cc: "Serge E. Hallyn" Signed-off-by: Andrew Morton

reboot: rename now misleading __hw_protection_shutdown symbols

2025-03-17T06:24:13Z

The __hw_protection_shutdown function name has become misleading since it can cause either a shutdown (poweroff) or a reboot depending on its argument. To avoid further confusion, let's rename it, so it doesn't suggest that a poweroff is all it can do. Link: https://lkml.kernel.org/r/20250217-hw_protection-reboot-v3-5-e1c09b090c0c@pengutronix.de Signed-off-by: Ahmad Fatoum Reviewed-by: Tzung-Bi Shih Cc: Benson Leung Cc: Daniel Lezcano Cc: Fabio Estevam Cc: Guenter Roeck Cc: Jonathan Corbet Cc: Liam Girdwood Cc: Lukasz Luba Cc: Mark Brown Cc: Matteo Croce Cc: Matti Vaittinen Cc: "Rafael J. Wysocki" Cc: Rob Herring (Arm) Cc: Rui Zhang Cc: Sascha Hauer Cc: "Serge E. Hallyn" Signed-off-by: Andrew Morton

reboot: describe do_kernel_restart's cmd argument in kernel-doc

2025-03-17T06:24:13Z

A W=1 build rightfully complains about the function's kernel-doc being incomplete. Describe its single parameter to fix this. Link: https://lkml.kernel.org/r/20250217-hw_protection-reboot-v3-4-e1c09b090c0c@pengutronix.de Signed-off-by: Ahmad Fatoum Reviewed-by: Tzung-Bi Shih Cc: Benson Leung Cc: Daniel Lezcano Cc: Fabio Estevam Cc: Guenter Roeck Cc: Jonathan Corbet Cc: Liam Girdwood Cc: Lukasz Luba Cc: Mark Brown Cc: Matteo Croce Cc: Matti Vaittinen Cc: "Rafael J. Wysocki" Cc: Rob Herring (Arm) Cc: Rui Zhang Cc: Sascha Hauer Cc: "Serge E. Hallyn" Signed-off-by: Andrew Morton