From: Yang Yingliang yangyingliang@huawei.com
[ Upstream commit 9049e1ca41983ab773d7ea244bee86d7835ec9f5 ]
Fault injection tests trigger warnings like this:
kernfs: can not remove 'chip_name', no directory WARNING: CPU: 0 PID: 253 at fs/kernfs/dir.c:1616 kernfs_remove_by_name_ns+0xce/0xe0 RIP: 0010:kernfs_remove_by_name_ns+0xce/0xe0 Call Trace: <TASK> remove_files.isra.1+0x3f/0xb0 sysfs_remove_group+0x68/0xe0 sysfs_remove_groups+0x41/0x70 __kobject_del+0x45/0xc0 kobject_del+0x29/0x40 free_desc+0x42/0x70 irq_free_descs+0x5e/0x90
The reason is that the interrupt descriptor sysfs handling does not roll back on a failing kobject_add() during allocation. If the descriptor is freed later on, kobject_del() is invoked with a not added kobject resulting in the above warnings.
A proper rollback in case of a kobject_add() failure would be the straight forward solution. But this is not possible due to the way how interrupt descriptor sysfs handling works.
Interrupt descriptors are allocated before sysfs becomes available. So the sysfs files for the early allocated descriptors are added later in the boot process. At this point there can be nothing useful done about a failing kobject_add(). For consistency the interrupt descriptor allocation always treats kobject_add() failures as non-critical and just emits a warning.
To solve this problem, keep track in the interrupt descriptor whether kobject_add() was successful or not and make the invocation of kobject_del() conditional on that.
[ tglx: Massage changelog, comments and use a state bit. ]
Fixes: ecb3f394c5db ("genirq: Expose interrupt information through sysfs") Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Link: https://lore.kernel.org/r/20221128151612.1786122-1-yangyingliang@huawei.com Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/irq/internals.h | 2 ++ kernel/irq/irqdesc.c | 15 +++++++++------ 2 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index e58342ace11f..f1d83a8b4417 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -52,6 +52,7 @@ enum { * IRQS_PENDING - irq is pending and replayed later * IRQS_SUSPENDED - irq is suspended * IRQS_NMI - irq line is used to deliver NMIs + * IRQS_SYSFS - descriptor has been added to sysfs */ enum { IRQS_AUTODETECT = 0x00000001, @@ -64,6 +65,7 @@ enum { IRQS_SUSPENDED = 0x00000800, IRQS_TIMINGS = 0x00001000, IRQS_NMI = 0x00002000, + IRQS_SYSFS = 0x00004000, };
#include "debug.h" diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c index 21b3ac2a29d2..7a45fd593245 100644 --- a/kernel/irq/irqdesc.c +++ b/kernel/irq/irqdesc.c @@ -288,22 +288,25 @@ static void irq_sysfs_add(int irq, struct irq_desc *desc) if (irq_kobj_base) { /* * Continue even in case of failure as this is nothing - * crucial. + * crucial and failures in the late irq_sysfs_init() + * cannot be rolled back. */ if (kobject_add(&desc->kobj, irq_kobj_base, "%d", irq)) pr_warn("Failed to add kobject for irq %d\n", irq); + else + desc->istate |= IRQS_SYSFS; } }
static void irq_sysfs_del(struct irq_desc *desc) { /* - * If irq_sysfs_init() has not yet been invoked (early boot), then - * irq_kobj_base is NULL and the descriptor was never added. - * kobject_del() complains about a object with no parent, so make - * it conditional. + * Only invoke kobject_del() when kobject_add() was successfully + * invoked for the descriptor. This covers both early boot, where + * sysfs is not initialized yet, and the case of a failed + * kobject_add() invocation. */ - if (irq_kobj_base) + if (desc->istate & IRQS_SYSFS) kobject_del(&desc->kobj); }