Re: [ANNOUNCE] v6.3-rc2-rt3

[Pierre Gondois]

Hello Sebastian,
The following appears between v6.3-rc2-rt2 and v6.3-rc2-rt3,
it is probably due to b111e33ae076 ("printk: Update John's printk series.")

=============================
[ BUG: Invalid wait context ]
6.3.0-rc5-rt8-gacb52bd349a2 #417 Not tainted
-----------------------------
swapper/0/1 is trying to lock:
ffff00097eea1180 (cpu){....}-{3:3}, at: __printk_safe_enter (kernel/printk/printk_safe.c:28 (discriminator 3))
other info that might help us debug this:
context-{5:5}
1 lock held by swapper/0/1:
#0: ffff80000ba77028 (rcu_tasks_rude.cbs_gbl_lock){....}-{2:2}, at: cblist_init_generic (kernel/rcu/tasks.h:233)
stack backtrace:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.3.0-rc5-rt8-gacb52bd349a2 #417
Hardware name: ARM Juno development board (r2) (DT)
Call trace:
dump_backtrace (arch/arm64/kernel/stacktrace.c:160)
show_stack (arch/arm64/kernel/stacktrace.c:167)
dump_stack_lvl (lib/dump_stack.c:107)
dump_stack (lib/dump_stack.c:114)
__lock_acquire (kernel/locking/lockdep.c:4710)
lock_acquire (./arch/arm64/include/asm/percpu.h:40)
__printk_safe_enter (./include/linux/local_lock_internal.h:30 (discriminator 3))
__down_trylock_console_sem (kernel/printk/printk.c:327)
console_trylock (kernel/printk/printk.c:2710 (discriminator 4))
vprintk_emit (kernel/printk/printk.c:1960)
vprintk_default (kernel/printk/printk.c:2367)
vprintk (kernel/printk/printk_safe.c:69)
_printk (kernel/printk/printk.c:2380)
cblist_init_generic (kernel/rcu/tasks.h:236)
rcu_init_tasks_generic (kernel/rcu/tasks.h:1142)
kernel_init_freeable (./arch/arm64/include/asm/jump_label.h:21)
kernel_init (init/main.c:1530)
ret_from_fork (arch/arm64/kernel/entry.S:871)

Regards,
Pierre

On 3/14/23 18:12, Sebastian Andrzej Siewior wrote:
> On 2023-03-14 18:05:04 [+0100], To Thomas Gleixner wrote:
> > Dear RT folks!
> >
> > I'm pleased to announce the v6.3-rc2-rt3 patch set.
> >
> > Changes since v6.3-rc2-rt2:
> >
> >    - The i915 and other driver using io_mapping_map_atomic_wc() function
> >      could deadlock. Reported by Richard Weinberger.
> >
> >    - A larger printk rework by John Ogness. This printk series is based
> >      on the latest work by John and most of the patches have been
> >      submitted for upstream review.
> >      As in the previous version the concept of an atomic console
> >      remained. That means a crash (BUG(), panic(), …) without a atomic
> >      console driver remains invisible on PREEMPT_RT. The only available
> >      atomic console driver is the 8250 UART and has been tested on X86.
> >
> > Known issues
> >       - Crystal Wood reported that a filesystem (XFS) may deadlock while
> >         flushing during schedule.
> >
> > The delta patch against v6.3-rc2-rt2 is appended below and can be found here:
> >   
> >       https://cdn.kernel.org/pub/linux/kernel/projects/rt/6.3/incr/patch-6.3-rc2-rt2-rt3.patch.xz
> >
> > You can get this release via the git tree at:
> >
> >      git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v6.3-rc2-rt3
> >
> > The RT patch against v6.3-rc2 can be found here:
> >
> >      https://cdn.kernel.org/pub/linux/kernel/projects/rt/6.3/older/patch-6.3-rc2-rt3.patch.xz
> >
> > The split quilt queue is available at:
> >
> >      https://cdn.kernel.org/pub/linux/kernel/projects/rt/6.3/older/patches-6.3-rc2-rt3.tar.xz
>
> This email didn't pass the size restriction on linux-rt-users@ so this
> is just a small ping that this release happened. The whole email is in
> the archive:
> 	https://lore.kernel.org/20230314170502.OHw1_FK3@xxxxxxxxxxxxx
>   
> Sebastian