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author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-05-19 22:01:00 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-05-19 22:01:00 +0300 |
commit | a76056285f5d64740b461d70b062225ba80f0ac2 (patch) | |
tree | 6d84eddfa6dbe749c05e884250e2e4a1ef479ef4 /drivers | |
parent | 41c14f1ac82cdb1e009d635ffd5ae5dc4cc3f036 (diff) | |
parent | b2aba15ad6f908d1a620fd97f6af5620c3639742 (diff) | |
download | linux-a76056285f5d64740b461d70b062225ba80f0ac2.tar.xz |
Merge tag 'kgdb-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux
Pull kgdb updates from Daniel Thompson:
"Nine patches this cycle and they split into just three topics:
- Adopt coccinelle's recommendation to adopt str_plural()
- A set of seven patches to refactor kdb_read() to improve both code
clarity and its discipline with respect to fixed size buffers.
This isn't just a refactor. Between them these also fix a cursor
movement redraw problem and two buffer overflows (one latent and
one real, albeit difficult to tickle).
- Fix an NMI-safety problem when enqueuing kdb's keyboard reset code
I wrote eight of the nine patches in this collection so many thanks to
Doug Anderson for the reviews. The changes that affects
drivers/tty/serial is acked by Greg KH"
* tag 'kgdb-6.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
serial: kgdboc: Fix NMI-safety problems from keyboard reset code
kdb: Simplify management of tmpbuffer in kdb_read()
kdb: Replace double memcpy() with memmove() in kdb_read()
kdb: Use format-specifiers rather than memset() for padding in kdb_read()
kdb: Merge identical case statements in kdb_read()
kdb: Fix console handling when editing and tab-completing commands
kdb: Use format-strings rather than '\0' injection in kdb_read()
kdb: Fix buffer overflow during tab-complete
kdb: Use str_plural() to fix Coccinelle warning
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/tty/serial/kgdboc.c | 30 |
1 files changed, 29 insertions, 1 deletions
diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c index 7ce7bb164005..58ea1e1391ce 100644 --- a/drivers/tty/serial/kgdboc.c +++ b/drivers/tty/serial/kgdboc.c @@ -19,6 +19,7 @@ #include <linux/console.h> #include <linux/vt_kern.h> #include <linux/input.h> +#include <linux/irq_work.h> #include <linux/module.h> #include <linux/platform_device.h> #include <linux/serial_core.h> @@ -48,6 +49,25 @@ static struct kgdb_io kgdboc_earlycon_io_ops; static int (*earlycon_orig_exit)(struct console *con); #endif /* IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE) */ +/* + * When we leave the debug trap handler we need to reset the keyboard status + * (since the original keyboard state gets partially clobbered by kdb use of + * the keyboard). + * + * The path to deliver the reset is somewhat circuitous. + * + * To deliver the reset we register an input handler, reset the keyboard and + * then deregister the input handler. However, to get this done right, we do + * have to carefully manage the calling context because we can only register + * input handlers from task context. + * + * In particular we need to trigger the action from the debug trap handler with + * all its NMI and/or NMI-like oddities. To solve this the kgdboc trap exit code + * (the "post_exception" callback) uses irq_work_queue(), which is NMI-safe, to + * schedule a callback from a hardirq context. From there we have to defer the + * work again, this time using schedule_work(), to get a callback using the + * system workqueue, which runs in task context. + */ #ifdef CONFIG_KDB_KEYBOARD static int kgdboc_reset_connect(struct input_handler *handler, struct input_dev *dev, @@ -99,10 +119,17 @@ static void kgdboc_restore_input_helper(struct work_struct *dummy) static DECLARE_WORK(kgdboc_restore_input_work, kgdboc_restore_input_helper); +static void kgdboc_queue_restore_input_helper(struct irq_work *unused) +{ + schedule_work(&kgdboc_restore_input_work); +} + +static DEFINE_IRQ_WORK(kgdboc_restore_input_irq_work, kgdboc_queue_restore_input_helper); + static void kgdboc_restore_input(void) { if (likely(system_state == SYSTEM_RUNNING)) - schedule_work(&kgdboc_restore_input_work); + irq_work_queue(&kgdboc_restore_input_irq_work); } static int kgdboc_register_kbd(char **cptr) @@ -133,6 +160,7 @@ static void kgdboc_unregister_kbd(void) i--; } } + irq_work_sync(&kgdboc_restore_input_irq_work); flush_work(&kgdboc_restore_input_work); } #else /* ! CONFIG_KDB_KEYBOARD */ |