From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.7 required=3.0 tests=BAYES_00,FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3B88DC4361B for ; Wed, 16 Dec 2020 01:15:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 08399207E8 for ; Wed, 16 Dec 2020 01:15:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726567AbgLPBOx (ORCPT ); Tue, 15 Dec 2020 20:14:53 -0500 Received: from mail-il1-f197.google.com ([209.85.166.197]:53447 "EHLO mail-il1-f197.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726306AbgLPBOx (ORCPT ); Tue, 15 Dec 2020 20:14:53 -0500 Received: by mail-il1-f197.google.com with SMTP id q2so18086486ilt.20 for ; Tue, 15 Dec 2020 17:14:37 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=KqSiQgWhoD3U6R5hjEeNhCbfIfoF5Ak040X4OCRefZg=; b=RfnqvtcnoOXehXrZMBXO9vjpTKC0LuYv91VB+vQox3es1zdAPXgCM0idi2ODErSKjD KUm0hkgWl7d9VIaEJSgZuNXo+29IowRlyI9HlvHcjCjgBed7fJNoDL5pMuRsRtcS9Y6H TuQYyToUtCRsWrI1TyjmK3JpTRrWkMoYorkWHWwdDYyxw0Oeljw0dm5L4K2F/o06+rhD /QM0OKjUMxojv/b/WchhBrWlObORFb9IPprBuS9Y0sPnYOsOA/3a0Rc5K7sO002OaEh4 Vqq0B1+Od8KWOpPbtKM6fuhbFsoTlBxOTWiFsOlzCjkn8a/x9yDCXhy2xdPdTwv2PeVx rfaw== X-Gm-Message-State: AOAM531pA5PnhK3M/HELg/LSHigc4fYDmd9x0cXugrSr89Jrm8vtPDMJ YCaILR3DIHx3zCuzhDMsB6RZiia+NQDw1QZAHfjxk3TyXnnz X-Google-Smtp-Source: ABdhPJxRF4JnudYyVFdlpAzdNt/B5IVfef+TzU8B6YH08NhU0AOnllFroZDBsTTM1pVIHe4xLihNAz1VQMDxFLHqe3WV0FX66gtc MIME-Version: 1.0 X-Received: by 2002:a5d:8483:: with SMTP id t3mr27239384iom.35.1608081251984; Tue, 15 Dec 2020 17:14:11 -0800 (PST) Date: Tue, 15 Dec 2020 17:14:11 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <000000000000cb6db205b68a971c@google.com> Subject: WARNING: suspicious RCU usage in modeset_lock From: syzbot To: b.zolnierkie@samsung.com, daniel.vetter@ffwll.ch, dri-devel@lists.freedesktop.org, geert@linux-m68k.org, gustavoars@kernel.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, natechancellor@gmail.com, peda@axentia.se, penguin-kernel@i-love.sakura.ne.jp, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, syzbot found the following issue on: HEAD commit: 94801e5c Merge tag 'pinctrl-v5.10-3' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=130558c5500000 kernel config: https://syzkaller.appspot.com/x/.config?x=ee8a1012a5314210 dashboard link: https://syzkaller.appspot.com/bug?extid=972b924c988834e868b2 compiler: gcc (GCC) 10.1.0-syz 20200507 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+972b924c988834e868b2@syzkaller.appspotmail.com ============================= WARNING: suspicious RCU usage 5.10.0-rc7-syzkaller #0 Not tainted ----------------------------- kernel/sched/core.c:7270 Illegal context switch in RCU-sched read-side critical section! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 0 7 locks held by syz-executor.1/9232: #0: ffffffff8b328c60 (console_lock){+.+.}-{0:0}, at: do_fb_ioctl+0x2e4/0x690 drivers/video/fbdev/core/fbmem.c:1106 #1: ffff888041bd4078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:636 [inline] #1: ffff888041bd4078 (&fb_info->lock){+.+.}-{3:3}, at: do_fb_ioctl+0x2ee/0x690 drivers/video/fbdev/core/fbmem.c:1107 #2: ffff888041adca78 (&helper->lock){+.+.}-{3:3}, at: drm_fb_helper_pan_display+0xce/0x970 drivers/gpu/drm/drm_fb_helper.c:1448 #3: ffff8880159f01b8 (&dev->master_mutex){+.+.}-{3:3}, at: drm_master_internal_acquire+0x1d/0x70 drivers/gpu/drm/drm_auth.c:407 #4: ffff888041adc898 (&client->modeset_mutex){+.+.}-{3:3}, at: drm_client_modeset_commit_locked+0x44/0x580 drivers/gpu/drm/drm_client_modeset.c:1143 #5: ffffc90001c07730 (crtc_ww_class_acquire){+.+.}-{0:0}, at: drm_client_modeset_commit_atomic+0xb7/0x7c0 drivers/gpu/drm/drm_client_modeset.c:981 #6: ffff888015986108 (crtc_ww_class_mutex){+.+.}-{3:3}, at: ww_mutex_lock_slow include/linux/ww_mutex.h:287 [inline] #6: ffff888015986108 (crtc_ww_class_mutex){+.+.}-{3:3}, at: modeset_lock+0x31c/0x650 drivers/gpu/drm/drm_modeset_lock.c:260 stack backtrace: CPU: 1 PID: 9232 Comm: syz-executor.1 Not tainted 5.10.0-rc7-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 ___might_sleep+0x25d/0x2b0 kernel/sched/core.c:7270 __mutex_lock_common kernel/locking/mutex.c:935 [inline] __ww_mutex_lock.constprop.0+0xa9/0x2cc0 kernel/locking/mutex.c:1111 ww_mutex_lock+0x3d/0x170 kernel/locking/mutex.c:1190 modeset_lock+0x392/0x650 drivers/gpu/drm/drm_modeset_lock.c:263 drm_modeset_lock drivers/gpu/drm/drm_modeset_lock.c:342 [inline] drm_modeset_lock+0x50/0x90 drivers/gpu/drm/drm_modeset_lock.c:338 drm_atomic_get_plane_state+0x19d/0x510 drivers/gpu/drm/drm_atomic.c:481 drm_client_modeset_commit_atomic+0x225/0x7c0 drivers/gpu/drm/drm_client_modeset.c:994 drm_client_modeset_commit_locked+0x145/0x580 drivers/gpu/drm/drm_client_modeset.c:1145 pan_display_atomic drivers/gpu/drm/drm_fb_helper.c:1395 [inline] drm_fb_helper_pan_display+0x28b/0x970 drivers/gpu/drm/drm_fb_helper.c:1455 fb_pan_display+0x2f7/0x6c0 drivers/video/fbdev/core/fbmem.c:925 fb_set_var+0x57f/0xda0 drivers/video/fbdev/core/fbmem.c:1043 do_fb_ioctl+0x2f9/0x690 drivers/video/fbdev/core/fbmem.c:1108 fb_compat_ioctl+0x17c/0xaf0 drivers/video/fbdev/core/fbmem.c:1315 __do_compat_sys_ioctl+0x1d3/0x230 fs/ioctl.c:842 do_syscall_32_irqs_on arch/x86/entry/common.c:78 [inline] __do_fast_syscall_32+0x56/0x80 arch/x86/entry/common.c:137 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:160 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7fd8549 Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f55d20bc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000004601 RDX: 0000000020000240 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 detected fb_set_par error, error code: -16 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.