* [PATCH 0/2] sleeping functions in invalid context on panic fixes @ 2018-05-14 15:59 Nicholas Piggin 2018-05-14 15:59 ` [PATCH 1/2] powerpc/powernv: Fix opal_event_shutdown() called with interrupts disabled Nicholas Piggin 2018-05-14 15:59 ` [PATCH 2/2] powerpc/powernv: Fix NVRAM sleep in invalid context when crashing Nicholas Piggin 0 siblings, 2 replies; 5+ messages in thread From: Nicholas Piggin @ 2018-05-14 15:59 UTC (permalink / raw) To: linuxppc-dev; +Cc: Nicholas Piggin Here's a couple of fixes which seem to solve a problem where panics can hang forever rather than reboot after 10 seconds. The symptoms are that a CPU calls panic(), but later it is found in idle. Nicholas Piggin (2): powerpc/powernv: Fix opal_event_shutdown() called with interrupts disabled powerpc/powernv: Fix NVRAM sleep in invalid context when crashing arch/powerpc/platforms/powernv/opal-irqchip.c | 2 +- arch/powerpc/platforms/powernv/opal-nvram.c | 14 ++++++++++++-- 2 files changed, 13 insertions(+), 3 deletions(-) -- 2.17.0 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 1/2] powerpc/powernv: Fix opal_event_shutdown() called with interrupts disabled 2018-05-14 15:59 [PATCH 0/2] sleeping functions in invalid context on panic fixes Nicholas Piggin @ 2018-05-14 15:59 ` Nicholas Piggin 2018-05-21 10:01 ` [1/2] " Michael Ellerman 2018-05-14 15:59 ` [PATCH 2/2] powerpc/powernv: Fix NVRAM sleep in invalid context when crashing Nicholas Piggin 1 sibling, 1 reply; 5+ messages in thread From: Nicholas Piggin @ 2018-05-14 15:59 UTC (permalink / raw) To: linuxppc-dev; +Cc: Nicholas Piggin A kernel crash in process context that calls emergency_restart from panic will end up calling opal_event_shutdown with interrupts disabled but not in interrupt. This causes a sleeping function to be called which gives the following warning with sysrq+c: Rebooting in 10 seconds.. BUG: sleeping function called from invalid context at kernel/locking/mutex.c:238 in_atomic(): 0, irqs_disabled(): 1, pid: 7669, name: bash CPU: 20 PID: 7669 Comm: bash Tainted: G D W 4.17.0-rc5+ #3 Call Trace: dump_stack+0xb0/0xf4 (unreliable) ___might_sleep+0x174/0x1a0 mutex_lock+0x38/0xb0 __free_irq+0x68/0x460 free_irq+0x70/0xc0 opal_event_shutdown+0xb4/0xf0 opal_shutdown+0x24/0xa0 pnv_shutdown+0x28/0x40 machine_shutdown+0x44/0x60 machine_restart+0x28/0x80 emergency_restart+0x30/0x50 panic+0x2a0/0x328 oops_end+0x1ec/0x1f0 bad_page_fault+0xe8/0x154 handle_page_fault+0x34/0x38 --- interrupt: 300 at sysrq_handle_crash+0x44/0x60 LR = __handle_sysrq+0xfc/0x260 flag_spec.62335+0x12b844/0x1e8db4 (unreliable) __handle_sysrq+0xfc/0x260 write_sysrq_trigger+0xa8/0xb0 proc_reg_write+0xac/0x110 __vfs_write+0x6c/0x240 vfs_write+0xd0/0x240 ksys_write+0x6c/0x110 Fixes: 9f0fd0499d30 ("powerpc/powernv: Add a virtual irqchip for opal events") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/platforms/powernv/opal-irqchip.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/powerpc/platforms/powernv/opal-irqchip.c b/arch/powerpc/platforms/powernv/opal-irqchip.c index 9d1b8c0aaf93..05ffe05f0fdc 100644 --- a/arch/powerpc/platforms/powernv/opal-irqchip.c +++ b/arch/powerpc/platforms/powernv/opal-irqchip.c @@ -177,7 +177,7 @@ void opal_event_shutdown(void) if (!opal_irqs[i]) continue; - if (in_interrupt()) + if (in_interrupt() || irqs_disabled()) disable_irq_nosync(opal_irqs[i]); else free_irq(opal_irqs[i], NULL); -- 2.17.0 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [1/2] powerpc/powernv: Fix opal_event_shutdown() called with interrupts disabled 2018-05-14 15:59 ` [PATCH 1/2] powerpc/powernv: Fix opal_event_shutdown() called with interrupts disabled Nicholas Piggin @ 2018-05-21 10:01 ` Michael Ellerman 0 siblings, 0 replies; 5+ messages in thread From: Michael Ellerman @ 2018-05-21 10:01 UTC (permalink / raw) To: Nicholas Piggin, linuxppc-dev; +Cc: Nicholas Piggin On Mon, 2018-05-14 at 15:59:46 UTC, Nicholas Piggin wrote: > A kernel crash in process context that calls emergency_restart from > panic will end up calling opal_event_shutdown with interrupts disabled > but not in interrupt. This causes a sleeping function to be called > which gives the following warning with sysrq+c: > > Rebooting in 10 seconds.. > BUG: sleeping function called from invalid context at kernel/locking/mutex.c:238 > in_atomic(): 0, irqs_disabled(): 1, pid: 7669, name: bash > CPU: 20 PID: 7669 Comm: bash Tainted: G D W 4.17.0-rc5+ #3 > Call Trace: > dump_stack+0xb0/0xf4 (unreliable) > ___might_sleep+0x174/0x1a0 > mutex_lock+0x38/0xb0 > __free_irq+0x68/0x460 > free_irq+0x70/0xc0 > opal_event_shutdown+0xb4/0xf0 > opal_shutdown+0x24/0xa0 > pnv_shutdown+0x28/0x40 > machine_shutdown+0x44/0x60 > machine_restart+0x28/0x80 > emergency_restart+0x30/0x50 > panic+0x2a0/0x328 > oops_end+0x1ec/0x1f0 > bad_page_fault+0xe8/0x154 > handle_page_fault+0x34/0x38 > --- interrupt: 300 at sysrq_handle_crash+0x44/0x60 > LR = __handle_sysrq+0xfc/0x260 > flag_spec.62335+0x12b844/0x1e8db4 (unreliable) > __handle_sysrq+0xfc/0x260 > write_sysrq_trigger+0xa8/0xb0 > proc_reg_write+0xac/0x110 > __vfs_write+0x6c/0x240 > vfs_write+0xd0/0x240 > ksys_write+0x6c/0x110 > > Fixes: 9f0fd0499d30 ("powerpc/powernv: Add a virtual irqchip for opal events") > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/c0beffc4f4c658fde86d52c837e784 cheers ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH 2/2] powerpc/powernv: Fix NVRAM sleep in invalid context when crashing 2018-05-14 15:59 [PATCH 0/2] sleeping functions in invalid context on panic fixes Nicholas Piggin 2018-05-14 15:59 ` [PATCH 1/2] powerpc/powernv: Fix opal_event_shutdown() called with interrupts disabled Nicholas Piggin @ 2018-05-14 15:59 ` Nicholas Piggin 2018-05-17 14:55 ` [2/2] " Michael Ellerman 1 sibling, 1 reply; 5+ messages in thread From: Nicholas Piggin @ 2018-05-14 15:59 UTC (permalink / raw) To: linuxppc-dev; +Cc: Nicholas Piggin, stable Similarly to opal_event_shutdown, opal_nvram_write can be called in the crash path with irqs disabled. Special case the delay to avoid sleeping in invalid context. Cc: stable@vger.kernel.org # v3.2 Fixes: 3b8070335f ("powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops") Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/platforms/powernv/opal-nvram.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/powernv/opal-nvram.c b/arch/powerpc/platforms/powernv/opal-nvram.c index 1bceb95f422d..5584247f5029 100644 --- a/arch/powerpc/platforms/powernv/opal-nvram.c +++ b/arch/powerpc/platforms/powernv/opal-nvram.c @@ -44,6 +44,10 @@ static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index) return count; } +/* + * This can be called in the panic path with interrupts off, so use + * mdelay in that case. + */ static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index) { s64 rc = OPAL_BUSY; @@ -58,10 +62,16 @@ static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index) while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { rc = opal_write_nvram(__pa(buf), count, off); if (rc == OPAL_BUSY_EVENT) { - msleep(OPAL_BUSY_DELAY_MS); + if (in_interrupt() || irqs_disabled()) + mdelay(OPAL_BUSY_DELAY_MS); + else + msleep(OPAL_BUSY_DELAY_MS); opal_poll_events(NULL); } else if (rc == OPAL_BUSY) { - msleep(OPAL_BUSY_DELAY_MS); + if (in_interrupt() || irqs_disabled()) + mdelay(OPAL_BUSY_DELAY_MS); + else + msleep(OPAL_BUSY_DELAY_MS); } } -- 2.17.0 ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [2/2] powerpc/powernv: Fix NVRAM sleep in invalid context when crashing 2018-05-14 15:59 ` [PATCH 2/2] powerpc/powernv: Fix NVRAM sleep in invalid context when crashing Nicholas Piggin @ 2018-05-17 14:55 ` Michael Ellerman 0 siblings, 0 replies; 5+ messages in thread From: Michael Ellerman @ 2018-05-17 14:55 UTC (permalink / raw) To: Nicholas Piggin, linuxppc-dev; +Cc: stable, Nicholas Piggin On Mon, 2018-05-14 at 15:59:47 UTC, Nicholas Piggin wrote: > Similarly to opal_event_shutdown, opal_nvram_write can be called in > the crash path with irqs disabled. Special case the delay to avoid > sleeping in invalid context. > > Cc: stable@vger.kernel.org # v3.2 > Fixes: 3b8070335f ("powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops") > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Applied to powerpc fixes, thanks. https://git.kernel.org/powerpc/c/c1d2a31397ec51f0370f6bd17b19b3 cheers ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2018-05-21 10:01 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-05-14 15:59 [PATCH 0/2] sleeping functions in invalid context on panic fixes Nicholas Piggin 2018-05-14 15:59 ` [PATCH 1/2] powerpc/powernv: Fix opal_event_shutdown() called with interrupts disabled Nicholas Piggin 2018-05-21 10:01 ` [1/2] " Michael Ellerman 2018-05-14 15:59 ` [PATCH 2/2] powerpc/powernv: Fix NVRAM sleep in invalid context when crashing Nicholas Piggin 2018-05-17 14:55 ` [2/2] " Michael Ellerman
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