diff options
Diffstat (limited to 'debian/patches-rt/0024-printk-nbcon-Add-unsafe-flushing-on-panic.patch')
-rw-r--r-- | debian/patches-rt/0024-printk-nbcon-Add-unsafe-flushing-on-panic.patch | 125 |
1 files changed, 0 insertions, 125 deletions
diff --git a/debian/patches-rt/0024-printk-nbcon-Add-unsafe-flushing-on-panic.patch b/debian/patches-rt/0024-printk-nbcon-Add-unsafe-flushing-on-panic.patch deleted file mode 100644 index a63a8ac515..0000000000 --- a/debian/patches-rt/0024-printk-nbcon-Add-unsafe-flushing-on-panic.patch +++ /dev/null @@ -1,125 +0,0 @@ -From: John Ogness <john.ogness@linutronix.de> -Date: Fri, 20 Oct 2023 10:03:42 +0000 -Subject: [PATCH 24/48] printk: nbcon: Add unsafe flushing on panic -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.8/older/patches-6.8.2-rt11.tar.xz - -Add nbcon_atomic_flush_unsafe() to flush all nbcon consoles -using the write_atomic() callback and allowing unsafe hostile -takeovers. Call this at the end of panic() as a final attempt -to flush any pending messages. - -Note that legacy consoles use unsafe methods for flushing -from the beginning of panic (see bust_spinlocks()). Therefore, -systems using both legacy and nbcon consoles may still fail to -see panic messages due to unsafe legacy console usage. - -Signed-off-by: John Ogness <john.ogness@linutronix.de> -Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> ---- - include/linux/printk.h | 5 +++++ - kernel/panic.c | 1 + - kernel/printk/nbcon.c | 26 +++++++++++++++++++++----- - 3 files changed, 27 insertions(+), 5 deletions(-) - ---- a/include/linux/printk.h -+++ b/include/linux/printk.h -@@ -197,6 +197,7 @@ extern asmlinkage void dump_stack(void) - void printk_trigger_flush(void); - extern void nbcon_driver_acquire(struct console *con); - extern void nbcon_driver_release(struct console *con); -+void nbcon_atomic_flush_unsafe(void); - #else - static inline __printf(1, 0) - int vprintk(const char *s, va_list args) -@@ -285,6 +286,10 @@ static inline void nbcon_driver_release( - { - } - -+static inline void nbcon_atomic_flush_unsafe(void) -+{ -+} -+ - #endif - - bool this_cpu_in_panic(void); ---- a/kernel/panic.c -+++ b/kernel/panic.c -@@ -453,6 +453,7 @@ void panic(const char *fmt, ...) - * Explicitly flush the kernel log buffer one last time. - */ - console_flush_on_panic(CONSOLE_FLUSH_PENDING); -+ nbcon_atomic_flush_unsafe(); - - local_irq_enable(); - for (i = 0; ; i += PANIC_TIMER_STEP) { ---- a/kernel/printk/nbcon.c -+++ b/kernel/printk/nbcon.c -@@ -1033,6 +1033,7 @@ bool nbcon_legacy_emit_next_record(struc - * write_atomic() callback - * @con: The nbcon console to flush - * @stop_seq: Flush up until this record -+ * @allow_unsafe_takeover: True, to allow unsafe hostile takeovers - * - * Return: True if taken over while printing. Otherwise false. - * -@@ -1041,7 +1042,8 @@ bool nbcon_legacy_emit_next_record(struc - * there are no more records available to read or this context is not allowed - * to acquire the console. - */ --static bool __nbcon_atomic_flush_pending_con(struct console *con, u64 stop_seq) -+static bool __nbcon_atomic_flush_pending_con(struct console *con, u64 stop_seq, -+ bool allow_unsafe_takeover) - { - struct nbcon_write_context wctxt = { }; - struct nbcon_context *ctxt = &ACCESS_PRIVATE(&wctxt, ctxt); -@@ -1049,6 +1051,7 @@ static bool __nbcon_atomic_flush_pending - ctxt->console = con; - ctxt->spinwait_max_us = 2000; - ctxt->prio = nbcon_get_default_prio(); -+ ctxt->allow_unsafe_takeover = allow_unsafe_takeover; - - if (!nbcon_context_try_acquire(ctxt)) - return false; -@@ -1075,8 +1078,9 @@ static bool __nbcon_atomic_flush_pending - * __nbcon_atomic_flush_pending - Flush all nbcon consoles using their - * write_atomic() callback - * @stop_seq: Flush up until this record -+ * @allow_unsafe_takeover: True, to allow unsafe hostile takeovers - */ --static void __nbcon_atomic_flush_pending(u64 stop_seq) -+static void __nbcon_atomic_flush_pending(u64 stop_seq, bool allow_unsafe_takeover) - { - struct console *con; - bool should_retry; -@@ -1109,8 +1113,8 @@ static void __nbcon_atomic_flush_pending - */ - local_irq_save(irq_flags); - -- should_retry |= __nbcon_atomic_flush_pending_con(con, stop_seq); -- -+ should_retry |= __nbcon_atomic_flush_pending_con(con, stop_seq, -+ allow_unsafe_takeover); - local_irq_restore(irq_flags); - } - console_srcu_read_unlock(cookie); -@@ -1127,7 +1131,19 @@ static void __nbcon_atomic_flush_pending - */ - void nbcon_atomic_flush_pending(void) - { -- __nbcon_atomic_flush_pending(prb_next_reserve_seq(prb)); -+ __nbcon_atomic_flush_pending(prb_next_reserve_seq(prb), false); -+} -+ -+/** -+ * nbcon_atomic_flush_unsafe - Flush all nbcon consoles using their -+ * write_atomic() callback and allowing unsafe hostile takeovers -+ * -+ * Flush the backlog up through the currently newest record. Unsafe hostile -+ * takeovers will be performed, if necessary. -+ */ -+void nbcon_atomic_flush_unsafe(void) -+{ -+ __nbcon_atomic_flush_pending(prb_next_reserve_seq(prb), true); - } - - /** |