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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0050-printk-Avoid-false-positive-lockdep-report-for-legac.patch | 64 |
1 files changed, 0 insertions, 64 deletions
diff --git a/debian/patches-rt/0050-printk-Avoid-false-positive-lockdep-report-for-legac.patch b/debian/patches-rt/0050-printk-Avoid-false-positive-lockdep-report-for-legac.patch deleted file mode 100644 index 7c9f453664..0000000000 --- a/debian/patches-rt/0050-printk-Avoid-false-positive-lockdep-report-for-legac.patch +++ /dev/null @@ -1,64 +0,0 @@ -From: John Ogness <john.ogness@linutronix.de> -Date: Mon, 11 Dec 2023 09:34:16 +0000 -Subject: [PATCH 50/50] printk: Avoid false positive lockdep report for legacy - driver. -Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.7/older/patches-6.7-rt6.tar.xz - -printk may invoke the legacy console driver from atomic context. This leads to -a lockdep splat because the console driver will acquire a sleeping lock and the -caller may also hold a spinning lock. This is noticed by lockdep on !PREEMPT_RT -configurations because it will also lead to a problem on PREEMPT_RT. - -On PREEMPT_RT the atomic path is always avoided and the console driver is -always invoked from a dedicated thread. Thus the lockdep splat is a false -positive. - -Override the lock-context before invoking the console driver. - -Signed-off-by: John Ogness <john.ogness@linutronix.de> -Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> ---- - kernel/printk/printk.c | 9 ++++++++- - 1 file changed, 8 insertions(+), 1 deletion(-) - ---- a/kernel/printk/printk.c -+++ b/kernel/printk/printk.c -@@ -2824,6 +2824,8 @@ static void __console_unlock(void) - up_console_sem(); - } - -+static DEFINE_WAIT_OVERRIDE_MAP(printk_legacy_map, LD_WAIT_SLEEP); -+ - #ifdef CONFIG_PRINTK - - /* -@@ -2992,7 +2994,7 @@ static bool console_emit_next_record(str - /* - * On PREEMPT_RT this function is either in a thread or - * panic context. So there is no need for concern about -- * printk reentrance or handovers. -+ * printk reentrance, handovers, or lockdep complaints. - */ - - con->write(con, outbuf, pmsg.outbuf_len); -@@ -3014,7 +3016,9 @@ static bool console_emit_next_record(str - /* Do not trace print latency. */ - stop_critical_timings(); - -+ lock_map_acquire_try(&printk_legacy_map); - con->write(con, outbuf, pmsg.outbuf_len); -+ lock_map_release(&printk_legacy_map); - - start_critical_timings(); - -@@ -3091,7 +3095,10 @@ static bool console_flush_all(bool do_co - any_usable = true; - - if (flags & CON_NBCON) { -+ -+ lock_map_acquire_try(&printk_legacy_map); - progress = nbcon_atomic_emit_next_record(con, handover, cookie); -+ lock_map_release(&printk_legacy_map); - - printk_seq = nbcon_seq_read(con); - } else { |