> > On Wed, May 19, 2021 at 08:00:28PM +0800, songqiang wrote: > > Signed-off-by: songqiang <songqiang@xxxxxxxxxxxxx> > From: "Matthew Wilcox <willy@xxxxxxxxxxxxx>" > > You need to explain: > > > > - Why you think this patch is needed > > - Did you observe a problem at runtime? > > - Is this the output from some checking tool? > > - Why this is the right way to address the problem > On Thu, May 20, 2021 at 7:58 AM 宋强 <songqiang@xxxxxxxxxxxxx> wrote: > > I find null pointer bug when I debug the kernel of loongson，I think the function fb_set_suspend() > add pointer judgment will more friendly. When replying to emails on the list, please remember - avoid top-posting, see https://git-send-email.io/top-posting.html - use plain text email, html replies get dropped by many mailing lists. The information from your reply should be part of the patch description when you send a patch, see https://www.kernel.org/doc/html/v4.17/process/submitting-patches.html > [ 102.011018] Call Trace: > > [ 102.013443] [<ffffffff81068e10>] fb_set_suspend+0x50/0x80 > [ 102.018819] [<ffffffffc0061aa0>] loongson_drm_suspend+0x1a0/0x340 [loongson] > [ 102.025827] [<ffffffffc0061c58>] loongson_pmops_freeze+0x18/0x40 [loongson] > [ 102.032748] [<ffffffff81008fd4>] pci_pm_freeze+0x94/0x240 > [ 102.038114] [<ffffffff815377e0>] dpm_run_callback.isra.5+0x20/0x140 > [ 102.044341] [<ffffffff81539608>] __device_suspend+0x2c8/0x740 It looks like the check would actually belong into the loongson_drm driver. The driver is not upstream yet, but I assume you have the source for it, so try to fix the bug there and send the patch to the owners of that driver. Arnd
