Hi Linus,
please pull the latest printk changes from
git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux.git tags/printk-for-6.9
========================================
Printk changes for 6.9 improve the behavior during panic. The issues were
found when testing the ongoing changes introducing atomic consoles and
printk kthreads.
- pr_flush() has to wait for the last reserved record instead
of the last finalized one. Note that records are finalized
in random order when generated by more CPUs in parallel.
- Ignore non-finalized records during panic(). Messages printed
on panic-CPU are always finalized. Messages printed by other
CPUs might never be finalized when the CPUs get stopped.
- Block new printk() calls on non-panic CPUs completely. Backtraces
are printed before entering the panic mode. Later messages
would just mess information printed by the panic CPU.
- Do not take console_lock in console_flush_on_panic() at all.
The original code did try_lock()/console_unlock(). The unlock part
might cause a deadlock when panic() happened in a scheduler code.
- Fix conversion of 64-bit sequence number for 32-bit atomic
operations.
----------------------------------------------------------------
John Ogness (12):
printk: nbcon: Relocate 32bit seq macros
printk: Use prb_first_seq() as base for 32bit seq macros
printk: ringbuffer: Do not skip non-finalized records with prb_next_seq()
printk: ringbuffer: Clarify special lpos values
printk: For @suppress_panic_printk check for other CPU in panic
printk: Add this_cpu_in_panic()
printk: ringbuffer: Cleanup reader terminology
printk: Wait for all reserved records with pr_flush()
printk: ringbuffer: Skip non-finalized records in panic
printk: Avoid non-panic CPUs writing to ringbuffer
panic: Flush kernel log buffer at the end
dump_stack: Do not get cpu_sync for panic CPU
Petr Mladek (1):
printk: Disable passing console lock owner completely during panic()
Sebastian Andrzej Siewior (1):
printk: Adjust mapping for 32bit seq macros
include/linux/printk.h | 2 +
kernel/panic.c | 8 +
kernel/printk/nbcon.c | 41 +----
kernel/printk/printk.c | 101 +++++++-----
kernel/printk/printk_ringbuffer.c | 337 ++++++++++++++++++++++++++++++++------
kernel/printk/printk_ringbuffer.h | 54 +++++-
lib/dump_stack.c | 16 +-
7 files changed, 420 insertions(+), 139 deletions(-)
The pull request you sent on Tue, 12 Mar 2024 15:54:57 +0100:
> git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux.git tags/printk-for-6.9
has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/b0546776ad3f332e215cebc0b063ba4351971cca
Thank you!
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