lkml.org 
[lkml]   [2019]   [Aug]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 84/98] genirq: Properly pair kobject_del() with kobject_add()
    Date
    From: Michael Kelley <mikelley@microsoft.com>

    commit d0ff14fdc987303aeeb7de6f1bd72c3749ae2a9b upstream.

    If alloc_descs() fails before irq_sysfs_init() has run, free_desc() in the
    cleanup path will call kobject_del() even though the kobject has not been
    added with kobject_add().

    Fix this by making the call to kobject_del() conditional on whether
    irq_sysfs_init() has run.

    This problem surfaced because commit aa30f47cf666 ("kobject: Add support
    for default attribute groups to kobj_type") makes kobject_del() stricter
    about pairing with kobject_add(). If the pairing is incorrrect, a WARNING
    and backtrace occur in sysfs_remove_group() because there is no parent.

    [ tglx: Add a comment to the code and make it work with CONFIG_SYSFS=n ]

    Fixes: ecb3f394c5db ("genirq: Expose interrupt information through sysfs")
    Signed-off-by: Michael Kelley <mikelley@microsoft.com>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: stable@vger.kernel.org
    Link: https://lkml.kernel.org/r/1564703564-4116-1-git-send-email-mikelley@microsoft.com
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    kernel/irq/irqdesc.c | 15 ++++++++++++++-
    1 file changed, 14 insertions(+), 1 deletion(-)

    --- a/kernel/irq/irqdesc.c
    +++ b/kernel/irq/irqdesc.c
    @@ -294,6 +294,18 @@ static void irq_sysfs_add(int irq, struc
    }
    }

    +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.
    + */
    + if (irq_kobj_base)
    + kobject_del(&desc->kobj);
    +}
    +
    static int __init irq_sysfs_init(void)
    {
    struct irq_desc *desc;
    @@ -324,6 +336,7 @@ static struct kobj_type irq_kobj_type =
    };

    static void irq_sysfs_add(int irq, struct irq_desc *desc) {}
    +static void irq_sysfs_del(struct irq_desc *desc) {}

    #endif /* CONFIG_SYSFS */

    @@ -437,7 +450,7 @@ static void free_desc(unsigned int irq)
    * The sysfs entry must be serialized against a concurrent
    * irq_sysfs_init() as well.
    */
    - kobject_del(&desc->kobj);
    + irq_sysfs_del(desc);
    delete_irq_desc(irq);

    /*

    \
     
     \ /
      Last update: 2019-08-27 09:59    [W:5.104 / U:0.840 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site