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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 03D8B1F458 X-Spam-Level: X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Rspamd-Action: no action X-Spam-Flag: NO X-Spamd-Result: default: False [-12.00 / 50.00]; SUSE_INTERNAL_BYPASS(-9.00)[]; BAYES_HAM(-3.00)[100.00%]; SUSPICIOUS_RECIPS(1.50)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; XM_UA_NO_VERSION(0.01)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; FREEMAIL_ENVRCPT(0.00)[gmail.com]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; FREEMAIL_CC(0.00)[linux.intel.com,kernel.org,gmail.com,ffwll.ch,vger.kernel.org,syzkaller.appspotmail.com]; DKIM_TRACE(0.00)[suse.de:+]; TO_DN_SOME(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCVD_TLS_ALL(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; RCPT_COUNT_SEVEN(0.00)[8]; RCVD_VIA_SMTP_AUTH(0.00)[]; TAGGED_RCPT(0.00)[369ee6a6e9d0bbf14b37]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:rdns,imap1.dmz-prg2.suse.org:helo,suse.de:dkim,appspotmail.com:email,chinamobile.com:email,syzkaller.appspot.com:url,suse.com:url] X-Spam-Score: -12.00 Am 11.11.26 um 05:41 schrieb Jiahao Xu: > The fbdev dirty callback (drm_atomic_helper_dirtyfb()) can fail with > -ENOMEM when the atomic commit allocation fails under memory pressure. > That is a transient runtime condition, not a driver bug: the damage is > only cosmetic and the frame is redrawn on the next flush. Cosmetic? Failing to allocate memory seems like a significant problem to me. > > drm_WARN_ONCE() turns this recoverable failure into a WARN splat (and a > panic with panic_on_warn), which syzbot keeps reporting: > > virtio-pci 0000:00:01.0: [drm] Dirty helper failed: ret=-12 > WARNING: drivers/gpu/drm/drm_fbdev_shmem.c:118 at ... > > Keep the warning for other failures, but do not warn about -ENOMEM. The > error is still propagated to the caller. > > Fixes: 150f431a0831 ("drm/fbdev: Add fbdev-shmem") > Reported-by: syzbot+369ee6a6e9d0bbf14b37@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=369ee6a6e9d0bbf14b37 > Signed-off-by: Jiahao Xu > --- > v2: > - Add the Fixes: tag reported by sashiko-bot. No code change. > --- > drivers/gpu/drm/drm_fbdev_shmem.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_fbdev_shmem.c b/drivers/gpu/drm/drm_fbdev_shmem.c > index 8eb05fe9b..c3fa5a663 100644 > --- a/drivers/gpu/drm/drm_fbdev_shmem.c > +++ b/drivers/gpu/drm/drm_fbdev_shmem.c > @@ -115,7 +115,14 @@ static int drm_fbdev_shmem_helper_fb_dirty(struct drm_fb_helper *helper, > > if (helper->fb->funcs->dirty) { > ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1); > - if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret)) > + /* > + * An allocation failure is a transient condition under memory > + * pressure, not a driver bug, so don't warn about it. The > + * error itself is still propagated to the caller. > + */ > + drm_WARN_ONCE(dev, ret && ret != -ENOMEM, > + "Dirty helper failed: ret=%d\n", ret); > + if (ret) > return ret; > } > -- -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com GF: Stefan Gaiser, Jochen Jaser, Abhinav Puri, (HRB 36809, AG Nürnberg)