Messages in this thread Patch in this message |  | | From | Samuel Holland <> | Subject | [PATCH v2 1/2] kernel/reboot: Use the static sys-off handler for any priority | Date | Sun, 1 Jan 2023 12:17:14 -0600 |
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commit 587b9bfe0668 ("kernel/reboot: Use static handler for register_platform_power_off()") addded a statically-allocated handler so register_sys_off_handler() could be called before the slab allocator is available.
That behavior was limited to the SYS_OFF_PRIO_PLATFORM priority. However, it is also required for handlers such as PSCI on ARM and SBI on RISC-V, which should be registered at SYS_OFF_PRIO_FIRMWARE. Currently, this call stack crashes:
start_kernel() setup_arch() psci_dt_init() psci_0_2_init() register_sys_off_handler() kmem_cache_alloc()
Generalize the code to use the statically-allocated handler for the first registration, regardless of priority. Check .sys_off_cb for conflicts instead of .cb_data; some callbacks (e.g. firmware drivers) do not need any per-instance data, so .cb_data could be NULL.
Reviewed-by: Dmitry Osipenko <dmitry.osipenko@collabora.com> Signed-off-by: Samuel Holland <samuel@sholland.org> ---
Changes in v2: - Update commit messages
kernel/reboot.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/kernel/reboot.c b/kernel/reboot.c index 3bba88c7ffc6..38c18d4f0a36 100644 --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -327,7 +327,7 @@ static int sys_off_notify(struct notifier_block *nb, return handler->sys_off_cb(&data); } -static struct sys_off_handler platform_sys_off_handler; +static struct sys_off_handler early_sys_off_handler; static struct sys_off_handler *alloc_sys_off_handler(int priority) { @@ -338,10 +338,8 @@ static struct sys_off_handler *alloc_sys_off_handler(int priority) * Platforms like m68k can't allocate sys_off handler dynamically * at the early boot time because memory allocator isn't available yet. */ - if (priority == SYS_OFF_PRIO_PLATFORM) { - handler = &platform_sys_off_handler; - if (handler->cb_data) - return ERR_PTR(-EBUSY); + if (!early_sys_off_handler.sys_off_cb) { + handler = &early_sys_off_handler; } else { if (system_state > SYSTEM_RUNNING) flags = GFP_ATOMIC; @@ -358,7 +356,7 @@ static struct sys_off_handler *alloc_sys_off_handler(int priority) static void free_sys_off_handler(struct sys_off_handler *handler) { - if (handler == &platform_sys_off_handler) + if (handler == &early_sys_off_handler) memset(handler, 0, sizeof(*handler)); else kfree(handler); -- 2.37.4
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