On 07/17/2015 05:46 AM, Thomas Huth wrote: > The EPOW interrupt handler uses rtas_get_sensor(), which in turn > uses rtas_busy_delay() to wait for RTAS becoming ready in case it > is necessary. But rtas_busy_delay() is annotated with might_sleep() > and thus may not be used by interrupts handlers like the EPOW handler! > This leads to the following BUG when CONFIG_DEBUG_ATOMIC_SLEEP is > enabled: > > BUG: sleeping function called from invalid context at arch/powerpc/kernel/rtas.c:496 > in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/1 > CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.2.0-rc2-thuth #6 > Call Trace: > [c00000007ffe7b90] [c000000000807670] dump_stack+0xa0/0xdc (unreliable) > [c00000007ffe7bc0] [c0000000000e1f14] ___might_sleep+0x134/0x180 > [c00000007ffe7c20] [c00000000002aec0] rtas_busy_delay+0x30/0xd0 > [c00000007ffe7c50] [c00000000002bde4] rtas_get_sensor+0x74/0xe0 > [c00000007ffe7ce0] [c000000000083264] ras_epow_interrupt+0x44/0x450 > [c00000007ffe7d90] [c000000000120260] handle_irq_event_percpu+0xa0/0x300 > [c00000007ffe7e70] [c000000000120524] handle_irq_event+0x64/0xc0 > [c00000007ffe7eb0] [c000000000124dbc] handle_fasteoi_irq+0xec/0x260 > [c00000007ffe7ef0] [c00000000011f4f0] generic_handle_irq+0x50/0x80 > [c00000007ffe7f20] [c000000000010f3c] __do_irq+0x8c/0x200 > [c00000007ffe7f90] [c0000000000236cc] call_do_irq+0x14/0x24 > [c00000007e6f39e0] [c000000000011144] do_IRQ+0x94/0x110 > [c00000007e6f3a30] [c000000000002594] hardware_interrupt_common+0x114/0x180 > > Fix this issue by introducing a new rtas_get_sensor_fast() function > that does not use rtas_busy_delay() - and thus can only be used for > sensors that do not cause a BUSY condition (which should be the case > for the sensor that is queried by the EPOW IRQ handler). > > Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx> Reviewed-by: Nathan Fontenot <nfont@xxxxxxxxxxxxxxxxxx> > --- > arch/powerpc/include/asm/rtas.h | 1 + > arch/powerpc/kernel/rtas.c | 17 +++++++++++++++++ > arch/powerpc/platforms/pseries/ras.c | 3 ++- > 3 files changed, 20 insertions(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
