Thomas Gleixner cba6437a18 genirq/proc: Reject invalid affinity masks (again) ... Qian Cai reported that the WARN_ON() in the x86/msi affinity setting code, which catches cases where the affinity setting is not done on the CPU which is the current target of the interrupt, triggers during CPU hotplug stress testing. It turns out that the warning which was added with the commit addressing the MSI affinity race unearthed yet another long standing bug. If user space writes a bogus affinity mask, i.e. it contains no online CPUs, then it calls irq_select_affinity_usr(). This was introduced for ALPHA in eee45269b0 ("[PATCH] Alpha: convert to generic irq framework (generic part)") and subsequently made available for all architectures in 1840475676 ("genirq: Expose default irq affinity mask (take 3)") which introduced the circumvention of the affinity setting restrictions for interrupt which cannot be moved in process context. The whole exercise is bogus in various aspects: 1) If the interrupt is already started up then there is absolutely no point to honour a bogus interrupt affinity setting from user space. The interrupt is already assigned to an online CPU and it does not make any sense to reassign it to some other randomly chosen online CPU. 2) If the interupt is not yet started up then there is no point either. A subsequent startup of the interrupt will invoke irq_setup_affinity() anyway which will chose a valid target CPU. So the only correct solution is to just return -EINVAL in case user space wrote an affinity mask which does not contain any online CPUs, except for ALPHA which has it's own magic sauce for this. Fixes: 1840475676 ("genirq: Expose default irq affinity mask (take 3)") Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Qian Cai <cai@lca.pw> Link: https://lkml.kernel.org/r/878sl8xdbm.fsf@nanos.tec.linutronix.de		2020-02-14 09:43:17 +01:00
..
affinity.c	genirq/affinity: Remove const qualifier from node_to_cpumask argument	2019-08-28 12:20:43 +02:00
autoprobe.c	genirq: Delay deactivation in free_irq()	2019-07-03 10:12:28 +02:00
chip.c	genirq: Introduce irq_chip_get/set_parent_state calls	2019-11-16 10:20:02 +00:00
cpuhotplug.c	genirq, sched/isolation: Isolate from handling managed interrupts	2020-01-22 16:29:49 +01:00
debug.h
debugfs.c	x86/apic/msi: Plug non-maskable MSI affinity race	2020-02-01 09:31:47 +01:00
devres.c
dummychip.c
generic-chip.c
handle.c
internals.h	genirq/proc: Reject invalid affinity masks (again)	2020-02-14 09:43:17 +01:00
ipi.c
irq_sim.c
irqdesc.c	genirq: Add missing __releases() sparse annotation	2020-01-09 18:03:24 +01:00
irqdomain.c	irqdomain: Fix a memory leak in irq_domain_push_irq()	2020-01-20 19:10:05 +00:00
Kconfig	treewide: Add SPDX license identifier - Makefile/Kconfig	2019-05-21 10:50:46 +02:00
Makefile	genirq/timings: Add selftest for circular array	2019-06-12 10:47:04 +02:00
manage.c	genirq/proc: Reject invalid affinity masks (again)	2020-02-14 09:43:17 +01:00
matrix.c
migration.c
msi.c	x86/apic/msi: Plug non-maskable MSI affinity race	2020-02-01 09:31:47 +01:00
pm.c	PCI: irq: Introduce rearm_wake_irq()	2019-07-23 09:37:51 +02:00
proc.c	genirq/proc: Reject invalid affinity masks (again)	2020-02-14 09:43:17 +01:00
resend.c	genirq: Prevent NULL pointer dereference in resend_irqs()	2019-09-05 21:31:14 +02:00
settings.h
spurious.c	genirq: Add missing __must_hold() sparse annotation	2020-01-09 18:03:37 +01:00
timings.c	genirq/timings: Add selftest for next event computation	2019-06-12 10:47:05 +02:00