On Sun, Apr 04, 2021 at 08:39:34PM +0800, Hillf Danton wrote: > On Sun, 4 Apr 2021 17:05:17 Hao Sun wrote: > > Besides, the 'refcount bug in cdev_del' bug still exists too. > > Thanks for your report, Hao. > > > > Here is the detailed information: > > commit: 5e46d1b78a03d52306f21f77a4e4a144b6d31486 > > version: Linux 5.12-rc5 > > git tree: upstream > > kernel config (KASAN not enabled) and reproducing program can be found > > in the attachment. > > Report: > > ------------[ cut here ]------------ > > refcount_t: underflow; use-after-free. > > WARNING: CPU: 1 PID: 8923 at lib/refcount.c:28 > > refcount_warn_saturate+0x1cf/0x210 -origin/lib/refcount.c:28 > > Modules linked in: > > CPU: 1 PID: 8923 Comm: executor Not tainted 5.12.0-rc5+ #8 > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS > > 1.13.0-1ubuntu1.1 04/01/2014 > > RIP: 0010:refcount_warn_saturate+0x1cf/0x210 -origin/lib/refcount.c:28 > > Code: 4f ff ff ff e8 32 fa b5 fe 48 c7 c7 3d f8 f6 86 e8 d6 ab c6 fe > > c6 05 7c 34 67 04 01 48 c7 c7 68 f8 6d 86 31 c0 e8 81 2e 9d fe <0f> 0b > > e9 22 ff ff ff e8 05 fa b5 fe 48 c7 c7 3e f8 f6 86 e8 a9 ab > > RSP: 0018:ffffc90001633c60 EFLAGS: 00010246 > > RAX: 15d08b2e34b77800 RBX: 0000000000000003 RCX: ffff88804c056c80 > > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 > > RBP: 0000000000000003 R08: ffffffff813767aa R09: 0001ffffffffffff > > R10: 0001ffffffffffff R11: ffff88804c056c80 R12: ffff888040b7d000 > > R13: ffff88804c206938 R14: ffff88804c206900 R15: ffff888041b18488 > > FS: 00000000022c9940(0000) GS:ffff88807ec00000(0000) knlGS:000000000000000= > > 0 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00007f9f9b122008 CR3: 0000000044b4b000 CR4: 0000000000750ee0 > > PKRU: 55555554 > > Call Trace: > > __refcount_sub_and_test -origin/./include/linux/refcount.h:283 [inline] > > __refcount_dec_and_test -origin/./include/linux/refcount.h:315 [inline] > > refcount_dec_and_test -origin/./include/linux/refcount.h:333 [inline] > > kref_put -origin/./include/linux/kref.h:64 [inline] > > kobject_put+0x17b/0x180 -origin/lib/kobject.c:753 > > cdev_del+0x4b/0x50 -origin/fs/char_dev.c:597 > > tty_unregister_device+0x99/0xd0 -origin/drivers/tty/tty_io.c:3343 > > gsmld_detach_gsm -origin/drivers/tty/n_gsm.c:2409 [inline] > > gsmld_close+0x6c/0x140 -origin/drivers/tty/n_gsm.c:2478 > > tty_ldisc_close -origin/drivers/tty/tty_ldisc.c:488 [inline] > > tty_ldisc_kill -origin/drivers/tty/tty_ldisc.c:636 [inline] > > tty_ldisc_release+0x1b6/0x400 -origin/drivers/tty/tty_ldisc.c:809 > > tty_release_struct+0x19/0xb0 -origin/drivers/tty/tty_io.c:1714 > > tty_release+0x9ad/0xa00 -origin/drivers/tty/tty_io.c:1885 > > __fput+0x260/0x4e0 -origin/fs/file_table.c:280 > > ____fput+0x11/0x20 -origin/fs/file_table.c:313 > > task_work_run+0x8e/0x110 -origin/kernel/task_work.c:140 > > tracehook_notify_resume -origin/./include/linux/tracehook.h:189 [inline] > > exit_to_user_mode_loop -origin/kernel/entry/common.c:174 [inline] > > exit_to_user_mode_prepare+0x16b/0x1a0 -origin/kernel/entry/common.c:208 > > __syscall_exit_to_user_mode_work -origin/kernel/entry/common.c:290 [inline] > > syscall_exit_to_user_mode+0x20/0x40 -origin/kernel/entry/common.c:301 > > do_syscall_64+0x45/0x80 -origin/arch/x86/entry/common.c:56 > > entry_SYSCALL_64_after_hwframe+0x44/0xae > > No error check on registering tty device - add it. > And roll back in case of error. > > --- x/drivers/tty/n_gsm.c > +++ y/drivers/tty/n_gsm.c > @@ -2384,8 +2384,19 @@ static int gsmld_attach_gsm(struct tty_s > /* Don't register device 0 - this is the control channel and not > a usable tty interface */ > base = mux_num_to_base(gsm); /* Base for this MUX */ > - for (i = 1; i < NUM_DLCI; i++) > - tty_register_device(gsm_tty_driver, base + i, NULL); > + for (i = 1; i < NUM_DLCI; i++) { > + struct device *dev; > + > + dev = tty_register_device(gsm_tty_driver, > + base + i, NULL); > + if (IS_ERR(dev)) { > + for (i--; i >= 1; i--) > + tty_unregister_device(gsm_tty_driver, > + base + i); > + ret = PTR_ERR(dev); > + return ret; > + } > + } > } > return ret; > }
Are you testing these patches somehow? Can you do that and then submit them correctly? thanks, greg k-h