On Sat, Nov 23, 2019 at 1:51 AM Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Thu, 21 Nov 2019, syzbot wrote: > > > Hello, > > > > syzbot found the following crash on: > > > > HEAD commit: 46178223 usb: gadget: add raw-gadget interface > > git tree: https://github.com/google/kasan.git usb-fuzzer > > console output: https://syzkaller.appspot.com/x/log.txt?x=15a05836e00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=99c88c44660624e7 > > dashboard link: https://syzkaller.appspot.com/bug?extid=ec5f884c4a135aa0dbb9 > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1061395ae00000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13653d1ce00000 > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+ec5f884c4a135aa0dbb9@xxxxxxxxxxxxxxxxxxxxxxxxx > > > > rcu: INFO: rcu_sched self-detected stall on CPU > > > RIP: 0010:hid_apply_multiplier drivers/hid/hid-core.c:1058 [inline] > > RIP: 0010:hid_setup_resolution_multiplier+0x33b/0x990 > > drivers/hid/hid-core.c:1114 I'm not sure, but the stack trace reminds me of this issue, so this report might be related: https://groups.google.com/d/msg/syzkaller-bugs/X0zVbh8aFEM/NsPcshjxBgAJ > > Diagnostic patch. > > #syz test: https://github.com/google/kasan.git 46178223 > > drivers/hid/hid-core.c | 17 +++++++++++++++-- > 1 file changed, 15 insertions(+), 2 deletions(-) > > Index: usb-devel/drivers/hid/hid-core.c > =================================================================== > --- usb-devel.orig/drivers/hid/hid-core.c > +++ usb-devel/drivers/hid/hid-core.c > @@ -1055,8 +1055,13 @@ static void hid_apply_multiplier(struct > */ > multiplier_collection = &hid->collection[multiplier->usage->collection_index]; > while (multiplier_collection->parent_idx != -1 && > - multiplier_collection->type != HID_COLLECTION_LOGICAL) > + multiplier_collection->type != HID_COLLECTION_LOGICAL) { > + hid_info(hid, "collection %d %px parent %d\n", > + multiplier_collection - hid->collection, multiplier_collection, > + multiplier_collection->parent_idx); > multiplier_collection = &hid->collection[multiplier_collection->parent_idx]; > + } > + hid_info(hid, "Got collection\n"); > > effective_multiplier = hid_calculate_multiplier(hid, multiplier); > > @@ -1069,6 +1074,7 @@ static void hid_apply_multiplier(struct > effective_multiplier); > } > } > + hid_info(hid, "Applied multiplier\n"); > } > > /* > @@ -1103,16 +1109,23 @@ void hid_setup_resolution_multiplier(str > > rep_enum = &hid->report_enum[HID_FEATURE_REPORT]; > list_for_each_entry(rep, &rep_enum->report_list, list) { > + hid_info(hid, "Start report %px maxfield %d\n", > + rep, rep->maxfield); > for (i = 0; i < rep->maxfield; i++) { > /* Ignore if report count is out of bounds. */ > if (rep->field[i]->report_count < 1) > continue; > > + hid_info(hid, "Field %d %px maxusage %d\n", > + i, rep->field[i], rep->field[i]->maxusage); > for (j = 0; j < rep->field[i]->maxusage; j++) { > usage = &rep->field[i]->usage[j]; > - if (usage->hid == HID_GD_RESOLUTION_MULTIPLIER) > + if (usage->hid == HID_GD_RESOLUTION_MULTIPLIER) { > + hid_info(hid, "Usage %d %px\n", > + j, usage); > hid_apply_multiplier(hid, > rep->field[i]); > + } > } > } > } >
