[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [Patch] fix xenfb_update_screen bogus rect
This looks bogus to me. check_is_dirty() definitely isn't needed - if at all, a memory read barrier may need to be added, but since kthread_should_stop() is a function call even that ought to be unnecessary. I also think the other change is more involved than it needs to be - it'd be much simpler to let xenfb_update_screen() check-and-clear the dirty flag along with reading the other fields, and bail if the flag was clear. Jan >>> Akio Takebe <takebe_akio@xxxxxxxxxxxxxx> 27.01.09 03:58 >>> Hi, When I tested pvfb, I got the following warnings. It seems to be caused by checking/setting info->dirty without dirty_lock. We need to check/set info->dirty safely. xenfb_update_screen bogus rect 2147483647 0 2147483647 0 BUG: warning at /root/linux-2.6.18-xen.hg/drivers/xen/fbfront/xenfb.c:240/xenfb_update_screen() Call Trace: [<ffffffff8036920e>] xenfb_thread+0x19b/0x2be [<ffffffff8022730a>] try_to_wake_up+0x33b/0x34c [<ffffffff80225c3d>] __wake_up_common+0x3e/0x68 [<ffffffff80241e20>] autoremove_wake_function+0x0/0x2e [<ffffffff80241a75>] keventd_create_kthread+0x0/0x61 [<ffffffff80369073>] xenfb_thread+0x0/0x2be [<ffffffff80241a75>] keventd_create_kthread+0x0/0x61 [<ffffffff80241ceb>] kthread+0xd4/0x109 [<ffffffff8020afe0>] child_rip+0xa/0x12 [<ffffffff80241a75>] keventd_create_kthread+0x0/0x61 [<ffffffff8021477f>] xen_send_IPI_mask+0x0/0xf5 [<ffffffff80241c17>] kthread+0x0/0x109 [<ffffffff8020afd6>] child_rip+0x0/0x12 FYI, when I tested it, I used the following shell scripts on PV guest. The above warnings occurred in /var/log/messages. ======================= #!/bin/bash while true do date done ======================= The attached patch fixed this warnings. How about it? Signed-off-by: Akio Takebe <takebe_akio@xxxxxxxxxxxxxx> Best Regards, Akio Takebe _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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