Syzbot reported divide error in vivid_thread_vid_cap, which has been seen only once and doesnot have a reproducer. This patch sanity checks for the denominator value with WARN_ON if it is 0 and replaces it with 1. Reported-by: syz...@xxxxxxxxxxxxxxxxxxxxxxxxx divide error: 0000 [#1] PREEMPT SMP KASAN kobject: 'tx-0' (0000000017161f7f): kobject_uevent_env CPU: 0 PID: 23689 Comm: vivid-003-vid-c Not tainted 5.0.0-rc4+ #58 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:vivid_cap_update_frame_period drivers/media/platform/vivid/vivid-kthread-cap.c:661 [inline] RIP: 0010:vivid_thread_vid_cap+0x221/0x284 drivers/media/platform/vivid/vivid-kthread-cap.c:789 Code: 48 c1 e9 03 0f b6 0c 11 48 89 f2 48 69 c0 00 ca 9a 3b 83 c2 03 38 ca 7c 08 84 c9 0f 85 f0 1e 00 00 41 8b 8f 24 64 00 00 31 d2 <48> f7 f1 49 89 c4 48 89 c3 49 8d 87 28 64 00 00 48 89 c2 48 89 45 RSP: 0018:ffff88808b4afd68 EFLAGS: 00010246 kobject: 'tx-0' (0000000017161f7f): fill_kobj_path: path = '/devices/virtual/net/gre0/queues/tx-0' RAX: 000000de5a6f8e00 RBX: 0000000100047b22 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004 RBP: ffff88808b4aff00 R08: ffff88804862e1c0 R09: ffffffff89997008 R10: ffffffff89997010 R11: 0000000000000001 R12: 00000000fffffffc R13: ffff8880a17e0500 R14: ffff88803e40f760 R15: ffff8882182b0140 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004cdc90 CR3: 000000005d827000 CR4: 00000000001426f0 Call Trace: kobject: 'gretap0' (00000000d7549098): kobject_add_internal: parent: 'net', set: 'devices' kobject: 'loop2' (0000000094ed4ee4): kobject_uevent_env kobject: 'loop2' (0000000094ed4ee4): fill_kobj_path: path = '/devices/virtual/block/loop2' kthread+0x357/0x430 kernel/kthread.c:246 kobject: 'gretap0' (00000000d7549098): kobject_uevent_env ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Modules linked in: kobject: 'gretap0' (00000000d7549098): fill_kobj_path: path = '/devices/virtual/net/gretap0' ---[ end trace bc5c8b25b64d768f ]--- kobject: 'loop1' (0000000032036b86): kobject_uevent_env RIP: 0010:vivid_cap_update_frame_period drivers/media/platform/vivid/vivid-kthread-cap.c:661 [inline] RIP: 0010:vivid_thread_vid_cap+0x221/0x2840 drivers/media/platform/vivid/vivid-kthread-cap.c:789 kobject: 'loop1' (0000000032036b86): fill_kobj_path: path = '/devices/virtual/block/loop1' Code: 48 c1 e9 03 0f b6 0c 11 48 89 f2 48 69 c0 00 ca 9a 3b 83 c2 03 38 ca 7c 08 84 c9 0f 85 f0 1e 00 00 41 8b 8f 24 64 00 00 31 d2 <48> f7 f1 49 89 c4 48 89 c3 49 8d 87 28 64 00 00 48 89 c2 48 89 45 kobject: 'loop0' (00000000dd9927c3): kobject_uevent_env RSP: 0018:ffff88808b4afd68 EFLAGS: 00010246 RAX: 000000de5a6f8e00 RBX: 0000000100047b22 RCX: 0000000000000000 kobject: 'queues' (000000007ed20666): kobject_add_internal: parent: 'gretap0', set: '<NULL>' RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000004 RBP: ffff88808b4aff00 R08: ffff88804862e1c0 R09: ffffffff89997008 kobject: 'loop0' (00000000dd9927c3): fill_kobj_path: path = '/devices/virtual/block/loop0' R10: ffffffff89997010 R11: 0000000000000001 R12: 00000000fffffffc kobject: 'queues' (000000007ed20666): kobject_uevent_env R13: ffff8880a17e0500 R14: ffff88803e40f760 R15: ffff8882182b0140 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 kobject: 'loop5' (00000000a41f9e79): kobject_uevent_env CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 kobject: 'queues' (000000007ed20666): kobject_uevent_env: filter function caused the event to drop! CR2: 00000000004cdc90 CR3: 000000005d827000 CR4: 00000000001426f0 kobject: 'loop5' (00000000a41f9e79): fill_kobj_path: path = '/devices/virtual/block/loop5' Signed-off-by: Vandana BN <bnvandana@xxxxxxxxx> --- drivers/media/platform/vivid/vivid-kthread-cap.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/media/platform/vivid/vivid-kthread-cap.c b/drivers/media/platform/vivid/vivid-kthread-cap.c index f8006a30c12f..025a8c68bd1c 100644 --- a/drivers/media/platform/vivid/vivid-kthread-cap.c +++ b/drivers/media/platform/vivid/vivid-kthread-cap.c @@ -658,6 +658,8 @@ static void vivid_cap_update_frame_period(struct vivid_dev *dev) u64 f_period; f_period = (u64)dev->timeperframe_vid_cap.numerator * 1000000000; + if(WARN_ON(dev->timeperframe_vid_cap.denominator == 0)) + dev->timeperframe_vid_cap.denominator = 1; do_div(f_period, dev->timeperframe_vid_cap.denominator); if (dev->field_cap == V4L2_FIELD_ALTERNATE) f_period >>= 1; -- 2.17.1
