lkml.org 
[lkml]   [2008]   [Oct]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    SubjectRe: [RFC 1/3] hvc_console: rework setup to replace irq functions with callbacks
    Date
    Am Montag, 13. Oktober 2008 schrieb Benjamin Herrenschmidt:
    >   ... key      at: [<c000000000939018>] proc_subdir_lock+0x18/0x38
    >  ... acquired at:
    >    [<c0000000000832e8>] .__lock_acquire+0x814/0x8ec
    >    [<c000000000083464>] .lock_acquire+0xa4/0xec
    >    [<c0000000004e713c>] ._spin_lock+0x44/0xa0
    >    [<c000000000139144>] .xlate_proc_name+0x50/0xf8
    >    [<c0000000001392f4>] .remove_proc_entry+0x44/0x298
    >    [<c0000000000a1e74>] .unregister_handler_proc+0x40/0x58
    >    [<c00000000009fc58>] .free_irq+0x124/0x18c
    >    [<c0000000002e6634>] .notifier_del_irq+0x28/0x48
    >    [<c0000000002e5ddc>] .hvc_close+0xa0/0x110
    >    [<c0000000002cc328>] .release_dev+0x244/0x580
    >    [<c0000000002cc688>] .tty_release+0x24/0x44
    >    [<c0000000000e5384>] .__fput+0xf8/0x1dc
    >    [<c0000000000e1bec>] .filp_close+0xb4/0xdc
    >    [<c0000000000e33a4>] .sys_close+0xac/0x100
    >    [<c0000000000084d4>] syscall_exit+0x0/0x40


    Hmmm.
    Can you try if this patch fixes the lockdep trace?

    This would be analog to
    commit b1b135c8d619cb2c7045d6ee4e48375882518bb5
    Author: Christian Borntraeger <borntraeger@de.ibm.com>
    Date: Thu Aug 7 09:18:34 2008 +0200

    fix spinlock recursion in hvc_console

    commit 611e097d7707741a336a0677d9d69bec40f29f3d
    Author: Christian Borntraeger <borntraeger@de.ibm.com>
    hvc_console: rework setup to replace irq functions with callbacks
    introduced a spinlock recursion problem.


    Signed-off-by: Christian Borntraeger<borntraeger@de.ibm.com>
    ---
    drivers/char/hvc_console.c | 10 +++++-----
    1 file changed, 5 insertions(+), 5 deletions(-)

    Index: linux-2.6/drivers/char/hvc_console.c
    ===================================================================
    --- linux-2.6.orig/drivers/char/hvc_console.c
    +++ linux-2.6/drivers/char/hvc_console.c
    @@ -367,13 +367,13 @@ static void hvc_close(struct tty_struct
    spin_lock_irqsave(&hp->lock, flags);

    if (--hp->count == 0) {
    - if (hp->ops->notifier_del)
    - hp->ops->notifier_del(hp, hp->data);
    -
    /* We are done with the tty pointer now. */
    hp->tty = NULL;
    spin_unlock_irqrestore(&hp->lock, flags);

    + if (hp->ops->notifier_del)
    + hp->ops->notifier_del(hp, hp->data);
    +
    /*
    * Chain calls chars_in_buffer() and returns immediately if
    * there is no buffered data otherwise sleeps on a wait queue
    @@ -416,11 +416,11 @@ static void hvc_hangup(struct tty_struct
    hp->n_outbuf = 0;
    hp->tty = NULL;

    + spin_unlock_irqrestore(&hp->lock, flags);
    +
    if (hp->ops->notifier_del)
    hp->ops->notifier_del(hp, hp->data);

    - spin_unlock_irqrestore(&hp->lock, flags);
    -
    while(temp_open_count) {
    --temp_open_count;
    kref_put(&hp->kref, destroy_hvc_struct);
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2008-10-13 09:55    [W:2.350 / U:1.392 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site