From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/pci/hotplug/TODO | 52 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 drivers/pci/hotplug/TODO (limited to 'drivers/pci/hotplug/TODO') diff --git a/drivers/pci/hotplug/TODO b/drivers/pci/hotplug/TODO new file mode 100644 index 000000000..7397374af --- /dev/null +++ b/drivers/pci/hotplug/TODO @@ -0,0 +1,52 @@ +Contributions are solicited in particular to remedy the following issues: + +cpcihp: + +* Returned code from pci_hp_add_bridge() is not checked. + +cpqphp: + +* The driver spawns a kthread cpqhp_event_thread() which is woken by the + hardirq handler cpqhp_ctrl_intr(). Convert this to threaded IRQ handling. + The kthread is also woken from the timer pushbutton_helper_thread(), + convert it to call irq_wake_thread(). Use pciehp as a template. + +* A large portion of cpqphp_ctrl.c and cpqphp_pci.c concerns resource + management. Doesn't this duplicate functionality in the core? + +* Returned code from pci_hp_add_bridge() is not checked. + +ibmphp: + +* Implementations of hotplug_slot_ops callbacks such as get_adapter_present() + in ibmphp_core.c create a copy of the struct slot on the stack, then perform + the actual operation on that copy. Determine if this overhead is necessary, + delete it if not. The functions also perform a NULL pointer check on the + struct hotplug_slot, this seems superfluous. + +* Several functions access the pci_slot member in struct hotplug_slot even + though pci_hotplug.h declares it private. See get_max_bus_speed() for an + example. Either the pci_slot member should no longer be declared private + or ibmphp should store a pointer to its bus in struct slot. Probably the + former. + +* ibmphp_init_devno() takes a struct slot **, it could instead take a + struct slot *. + +* The return value of pci_hp_register() is not checked. + +* The various slot data structures are difficult to follow and need to be + simplified. A lot of functions are too large and too complex, they need + to be broken up into smaller, manageable pieces. Negative examples are + ebda_rsrc_controller() and configure_bridge(). + +* A large portion of ibmphp_res.c and ibmphp_pci.c concerns resource + management. Doesn't this duplicate functionality in the core? + +* Returned code from pci_hp_add_bridge() is not checked. + +shpchp: + +* The hardirq handler shpc_isr() queues events on a workqueue. It can be + simplified by converting it to threaded IRQ handling. Use pciehp as a + template. -- cgit v1.3.1