* Re: [ANNOUNCE] v6.3-rc2-rt3 [not found] <20230314170502.OHw1_FK3@linutronix.de> @ 2023-03-14 17:12 ` Sebastian Andrzej Siewior 2023-04-14 11:55 ` Pierre Gondois 0 siblings, 1 reply; 7+ messages in thread From: Sebastian Andrzej Siewior @ 2023-03-14 17:12 UTC (permalink / raw) To: Thomas Gleixner; +Cc: LKML, linux-rt-users, Steven Rostedt 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@linutronix.de Sebastian ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [ANNOUNCE] v6.3-rc2-rt3 2023-03-14 17:12 ` [ANNOUNCE] v6.3-rc2-rt3 Sebastian Andrzej Siewior @ 2023-04-14 11:55 ` Pierre Gondois 2023-04-14 13:49 ` John Ogness 0 siblings, 1 reply; 7+ messages in thread From: Pierre Gondois @ 2023-04-14 11:55 UTC (permalink / raw) To: Sebastian Andrzej Siewior Cc: LKML, linux-rt-users, Steven Rostedt, Thomas Gleixner 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@linutronix.de > > Sebastian > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [ANNOUNCE] v6.3-rc2-rt3 2023-04-14 11:55 ` Pierre Gondois @ 2023-04-14 13:49 ` John Ogness 2023-04-14 13:56 ` Vlastimil Babka 0 siblings, 1 reply; 7+ messages in thread From: John Ogness @ 2023-04-14 13:49 UTC (permalink / raw) To: Pierre Gondois, Sebastian Andrzej Siewior Cc: LKML, linux-rt-users, Steven Rostedt, Thomas Gleixner Hi Pierre, On 2023-04-14, Pierre Gondois <pierre.gondois@arm.com> wrote: > ============================= > [ 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) This is actually a mainline issue relating to legacy consoles. In mainline you see it as a warning when CONFIG_PROVE_RAW_LOCK_NESTING is enabled. If you enable CONFIG_PREEMPT_RT you will not have the problem. I will look at how the issue can be gracefully ignored in !CONFIG_PREEMPT_RT. Thanks for reporting. John Ogness ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [ANNOUNCE] v6.3-rc2-rt3 2023-04-14 13:49 ` John Ogness @ 2023-04-14 13:56 ` Vlastimil Babka 2023-04-14 15:01 ` John Ogness 0 siblings, 1 reply; 7+ messages in thread From: Vlastimil Babka @ 2023-04-14 13:56 UTC (permalink / raw) To: John Ogness, Pierre Gondois, Sebastian Andrzej Siewior Cc: LKML, linux-rt-users, Steven Rostedt, Thomas Gleixner On 4/14/23 15:49, John Ogness wrote: > Hi Pierre, > > On 2023-04-14, Pierre Gondois <pierre.gondois@arm.com> wrote: >> ============================= >> [ 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) > > This is actually a mainline issue relating to legacy consoles. In > mainline you see it as a warning when CONFIG_PROVE_RAW_LOCK_NESTING is > enabled. > > If you enable CONFIG_PREEMPT_RT you will not have the problem. > > I will look at how the issue can be gracefully ignored in > !CONFIG_PREEMPT_RT. Is it perhaps a similar situation to this thread? https://lore.kernel.org/all/20230412124735.GE628377@hirez.programming.kicks-ass.net/ > Thanks for reporting. > > John Ogness ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [ANNOUNCE] v6.3-rc2-rt3 2023-04-14 13:56 ` Vlastimil Babka @ 2023-04-14 15:01 ` John Ogness 2023-04-14 15:38 ` Vlastimil Babka 0 siblings, 1 reply; 7+ messages in thread From: John Ogness @ 2023-04-14 15:01 UTC (permalink / raw) To: Vlastimil Babka, Pierre Gondois, Sebastian Andrzej Siewior Cc: LKML, linux-rt-users, Steven Rostedt, Thomas Gleixner On 2023-04-14, Vlastimil Babka <vbabka@suse.cz> wrote: > Is it perhaps a similar situation to this thread? > > https://lore.kernel.org/all/20230412124735.GE628377@hirez.programming.kicks-ass.net/ We are dealing with a spin_lock() inside a raw_spin_lock() section. The legacy console drivers do this. The fix is the new atomic/threaded consoles. For CONFIG_PREEMPT_RT a workaround is implemented so that the legacy consoles avoid this. For !CONFIG_PREEMPT_RT you can expect CONFIG_PROVE_RAW_LOCK_NESTING to cause a splat on that printk(). Or perhaps that particular printk() in cblist_init_generic() should be changed to printk_deferred() as a temporary whack-a-mole workaround. John Ogness ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [ANNOUNCE] v6.3-rc2-rt3 2023-04-14 15:01 ` John Ogness @ 2023-04-14 15:38 ` Vlastimil Babka 2023-04-18 15:08 ` Sebastian Andrzej Siewior 0 siblings, 1 reply; 7+ messages in thread From: Vlastimil Babka @ 2023-04-14 15:38 UTC (permalink / raw) To: John Ogness, Pierre Gondois, Sebastian Andrzej Siewior Cc: LKML, linux-rt-users, Steven Rostedt, Thomas Gleixner On 4/14/23 17:01, John Ogness wrote: > On 2023-04-14, Vlastimil Babka <vbabka@suse.cz> wrote: >> Is it perhaps a similar situation to this thread? >> >> https://lore.kernel.org/all/20230412124735.GE628377@hirez.programming.kicks-ass.net/ > > We are dealing with a spin_lock() inside a raw_spin_lock() section. The > legacy console drivers do this. The fix is the new atomic/threaded > consoles. For CONFIG_PREEMPT_RT a workaround is implemented so that the > legacy consoles avoid this. For !CONFIG_PREEMPT_RT you can expect > CONFIG_PROVE_RAW_LOCK_NESTING to cause a splat on that printk(). > > Or perhaps that particular printk() in cblist_init_generic() should be > changed to printk_deferred() as a temporary whack-a-mole > workaround. What I meant that in the linked thread a solution seems to be forming in the form of annotation for lockdep/CONFIG_PROVE_RAW_LOCK_NESTING to make it aware that on CONFIG_PREEMPT_RT the problem it sees is side-stepped so it shouldn't warn about it on !PREEMPT_RT, and maybe that solution could be used for the printk issue as well (I admit I didn't check the code, just by reading your mail it sounded very similar). > John Ogness ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [ANNOUNCE] v6.3-rc2-rt3 2023-04-14 15:38 ` Vlastimil Babka @ 2023-04-18 15:08 ` Sebastian Andrzej Siewior 0 siblings, 0 replies; 7+ messages in thread From: Sebastian Andrzej Siewior @ 2023-04-18 15:08 UTC (permalink / raw) To: Vlastimil Babka Cc: John Ogness, Pierre Gondois, LKML, linux-rt-users, Steven Rostedt, Thomas Gleixner On 2023-04-14 17:38:56 [+0200], Vlastimil Babka wrote: > What I meant that in the linked thread a solution seems to be forming in the > form of annotation for lockdep/CONFIG_PROVE_RAW_LOCK_NESTING to make it > aware that on CONFIG_PREEMPT_RT the problem it sees is side-stepped so it > shouldn't warn about it on !PREEMPT_RT, and maybe that solution could be > used for the printk issue as well (I admit I didn't check the code, just by > reading your mail it sounded very similar). Yes, you right and it would work and I would include it. Once the DEBUG_OBJECT part is merged (the LD_LOCK_WAIT logic is missing) I would add something here. Sebastian ^ permalink raw reply [flat|nested] 7+ messages in thread
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[not found] <20230314170502.OHw1_FK3@linutronix.de>
2023-03-14 17:12 ` [ANNOUNCE] v6.3-rc2-rt3 Sebastian Andrzej Siewior
2023-04-14 11:55 ` Pierre Gondois
2023-04-14 13:49 ` John Ogness
2023-04-14 13:56 ` Vlastimil Babka
2023-04-14 15:01 ` John Ogness
2023-04-14 15:38 ` Vlastimil Babka
2023-04-18 15:08 ` Sebastian Andrzej Siewior
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