Hello, syzbot found the following crash on: HEAD commit: ffeb595d Merge tag 'powerpc-5.7-6' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17f7f2b1100000 kernel config: https://syzkaller.appspot.com/x/.config?x=9ac87c7c2ba15abf dashboard link: https://syzkaller.appspot.com/bug?extid=b0de012ceb1e2a97891b compiler: clang version 10.0.0 (https://github.com/llvm/llvm-project/ c2443155a0fb245c8f17f2c1c72b6ea391e86e81) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+b0de012ceb1e2a97891b@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in usb_udc_uevent+0xac/0x120 drivers/usb/gadget/udc/core.c:1593 Read of size 8 at addr ffff888091a7c050 by task systemd-udevd/14223 CPU: 1 PID: 14223 Comm: systemd-udevd Not tainted 5.7.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1e9/0x30e lib/dump_stack.c:118 print_address_description+0x74/0x5c0 mm/kasan/report.c:382 __kasan_report+0x103/0x1a0 mm/kasan/report.c:511 kasan_report+0x4d/0x80 mm/kasan/common.c:625 Allocated by task 14178: save_stack mm/kasan/common.c:49 [inline] set_track mm/kasan/common.c:57 [inline] __kasan_kmalloc+0x114/0x160 mm/kasan/common.c:495 kmem_cache_alloc_trace+0x234/0x300 mm/slab.c:3551 kmalloc include/linux/slab.h:555 [inline] kzalloc include/linux/slab.h:669 [inline] dev_new drivers/usb/gadget/legacy/raw_gadget.c:182 [inline] raw_open+0x87/0x500 drivers/usb/gadget/legacy/raw_gadget.c:372 misc_open+0x346/0x3c0 drivers/char/misc.c:141 chrdev_open+0x498/0x580 fs/char_dev.c:414 do_dentry_open+0x82e/0x10b0 fs/open.c:797 do_open fs/namei.c:3229 [inline] path_openat+0x2790/0x38b0 fs/namei.c:3346 do_filp_open+0x191/0x3a0 fs/namei.c:3373 do_sys_openat2+0x463/0x770 fs/open.c:1148 do_sys_open fs/open.c:1164 [inline] ksys_open include/linux/syscalls.h:1386 [inline] __do_sys_open fs/open.c:1170 [inline] __se_sys_open fs/open.c:1168 [inline] __x64_sys_open+0x1af/0x1e0 fs/open.c:1168 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Freed by task 14174: save_stack mm/kasan/common.c:49 [inline] set_track mm/kasan/common.c:57 [inline] kasan_set_free_info mm/kasan/common.c:317 [inline] __kasan_slab_free+0x125/0x190 mm/kasan/common.c:456 __cache_free mm/slab.c:3426 [inline] kfree+0x10a/0x220 mm/slab.c:3757 raw_release+0x130/0x1e0 drivers/usb/gadget/legacy/raw_gadget.c:411 __fput+0x2ed/0x750 fs/file_table.c:280 task_work_run+0x147/0x1d0 kernel/task_work.c:123 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0x5ef/0x1f80 kernel/exit.c:796 do_group_exit+0x15e/0x2c0 kernel/exit.c:894 get_signal+0x13cf/0x1d60 kernel/signal.c:2739 do_signal+0x33/0x610 arch/x86/kernel/signal.c:784 exit_to_usermode_loop arch/x86/entry/common.c:161 [inline] prepare_exit_to_usermode+0x32a/0x600 arch/x86/entry/common.c:196 entry_SYSCALL_64_after_hwframe+0x49/0xb3 The buggy address belongs to the object at ffff888091a7c000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 80 bytes inside of 4096-byte region [ffff888091a7c000, ffff888091a7d000) The buggy address belongs to the page: page:ffffea0002469f00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea0002469f00 order:1 compound_mapcount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea0001043588 ffffea0001258b88 ffff8880aa402000 raw: 0000000000000000 ffff888091a7c000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888091a7bf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888091a7bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff888091a7c000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888091a7c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888091a7c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== --- This bug 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@xxxxxxxxxxxxxxxx. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
