On Thu, Jul 29, 2021 at 01:44:13PM +0200, Marcel Holtmann wrote: > Hi Phi, > > >> Hello, > >> syzbot found the following crash on: > >> HEAD commit: abf02e29 Merge tag 'pm-5.2-rc6' of > >> git://git.kernel.org/pu <http://git.kernel.org/pu>.. > >> git tree: upstream > >> console output: > >> https://syzkaller.appspot.com/x/log.txt?x=1054e6b2a00000 > >> <https://syzkaller.appspot.com/x/log.txt?x=1054e6b2a00000> > >> kernel config: > >> https://syzkaller.appspot.com/x/.config?x=56f1da14935c3cce > >> <https://syzkaller.appspot.com/x/.config?x=56f1da14935c3cce> > >> dashboard link: > >> https://syzkaller.appspot.com/bug?extid=97388eb9d31b997fe1d0 > >> <https://syzkaller.appspot.com/bug?extid=97388eb9d31b997fe1d0> > >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) > >> syz repro: > >> https://syzkaller.appspot.com/x/repro.syz?x=1073d8aaa00000 > >> <https://syzkaller.appspot.com/x/repro.syz?x=1073d8aaa00000> > >> C reproducer: > >> https://syzkaller.appspot.com/x/repro.c?x=17b36fbea00000 > >> <https://syzkaller.appspot.com/x/repro.c?x=17b36fbea00000> > >> IMPORTANT: if you fix the bug, please add the following tag to the > >> commit: > >> Reported-by: syzbot+97388e...@xxxxxxxxxxxxxxxxxxxxxxxxx > >> program > >> BUG: memory leak > >> unreferenced object 0xffff88810991fa00 (size 224): > >> comm "syz-executor739", pid 7080, jiffies 4294949854 (age 18.640s) > >> hex dump (first 32 bytes): > >> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > >> backtrace: > >> [<00000000da42c09f>] kmemleak_alloc_recursive > >> include/linux/kmemleak.h:43 [inline] > >> [<00000000da42c09f>] slab_post_alloc_hook mm/slab.h:439 [inline] > >> [<00000000da42c09f>] slab_alloc_node mm/slab.c:3269 [inline] > >> [<00000000da42c09f>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579 > >> [<00000000f6fbcf84>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:194 > >> [<00000000ea93fc4c>] alloc_skb include/linux/skbuff.h:1054 [inline] > >> [<00000000ea93fc4c>] bt_skb_alloc include/net/bluetooth/bluetooth.h:339 > >> [inline] > >> [<00000000ea93fc4c>] h4_recv_buf+0x26d/0x450 > >> drivers/bluetooth/hci_h4.c:182 > >> [<00000000e0312475>] h4_recv+0x51/0xb0 drivers/bluetooth/hci_h4.c:116 > >> [<00000000ebf11fab>] hci_uart_tty_receive+0xba/0x200 > >> drivers/bluetooth/hci_ldisc.c:592 > >> [<0000000095e1216e>] tiocsti drivers/tty/tty_io.c:2195 [inline] > >> [<0000000095e1216e>] tty_ioctl+0x81c/0xa30 drivers/tty/tty_io.c:2571 > >> [<000000009fa523f0>] vfs_ioctl fs/ioctl.c:46 [inline] > >> [<000000009fa523f0>] file_ioctl fs/ioctl.c:509 [inline] > >> [<000000009fa523f0>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696 > >> [<000000000cebb5d9>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713 > >> [<000000001630008a>] __do_sys_ioctl fs/ioctl.c:720 [inline] > >> [<000000001630008a>] __se_sys_ioctl fs/ioctl.c:718 [inline] > >> [<000000001630008a>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718 > >> [<00000000c62091e3>] do_syscall_64+0x76/0x1a0 > >> arch/x86/entry/common.c:301 > >> [<000000005c213625>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > >> BUG: memory leak > >> unreferenced object 0xffff8881204f4400 (size 1024): > >> comm "syz-executor739", pid 7080, jiffies 4294949854 (age 18.640s) > >> hex dump (first 32 bytes): > >> 6c 69 62 75 64 65 76 00 fe ed ca fe 28 00 00 00 libudev.....(... > >> 28 00 00 00 a0 00 00 00 52 ca da 77 00 00 00 00 (.......R..w.... > >> backtrace: > >> [<0000000034504843>] kmemleak_alloc_recursive > >> include/linux/kmemleak.h:43 [inline] > >> [<0000000034504843>] slab_post_alloc_hook mm/slab.h:439 [inline] > >> [<0000000034504843>] slab_alloc_node mm/slab.c:3269 [inline] > >> [<0000000034504843>] kmem_cache_alloc_node_trace+0x15b/0x2a0 > >> mm/slab.c:3597 > >> [<0000000056d30eb5>] __do_kmalloc_node mm/slab.c:3619 [inline] > >> [<0000000056d30eb5>] __kmalloc_node_track_caller+0x38/0x50 > >> mm/slab.c:3634 > >> [<00000000df40176c>] __kmalloc_reserve.isra.0+0x40/0xb0 > >> net/core/skbuff.c:138 > >> [<0000000035340e64>] __alloc_skb+0xa0/0x210 net/core/skbuff.c:206 > >> [<00000000ea93fc4c>] alloc_skb include/linux/skbuff.h:1054 [inline] > >> [<00000000ea93fc4c>] bt_skb_alloc include/net/bluetooth/bluetooth.h:339 > >> [inline] > >> [<00000000ea93fc4c>] h4_recv_buf+0x26d/0x450 > >> drivers/bluetooth/hci_h4.c:182 > >> [<00000000e0312475>] h4_recv+0x51/0xb0 drivers/bluetooth/hci_h4.c:116 > >> [<00000000ebf11fab>] hci_uart_tty_receive+0xba/0x200 > >> drivers/bluetooth/hci_ldisc.c:592 > >> [<0000000095e1216e>] tiocsti drivers/tty/tty_io.c:2195 [inline] > >> [<0000000095e1216e>] tty_ioctl+0x81c/0xa30 drivers/tty/tty_io.c:2571 > >> [<000000009fa523f0>] vfs_ioctl fs/ioctl.c:46 [inline] > >> [<000000009fa523f0>] file_ioctl fs/ioctl.c:509 [inline] > >> [<000000009fa523f0>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696 > >> [<000000000cebb5d9>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713 > >> [<000000001630008a>] __do_sys_ioctl fs/ioctl.c:720 [inline] > >> [<000000001630008a>] __se_sys_ioctl fs/ioctl.c:718 [inline] > >> [<000000001630008a>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718 > >> [<00000000c62091e3>] do_syscall_64+0x76/0x1a0 > >> arch/x86/entry/common.c:301 > >> [<000000005c213625>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 > >> --- > >> This bug is generated by a bot. It may contain errors. > >> See https://goo.gl/tpsmEJ <https://goo.gl/tpsmEJ> for more > >> information about syzbot. > >> syzbot engineers can be reached at syzk...@xxxxxxxxxxxxxxxx. > >> syzbot will keep track of this bug report. See: > >> https://goo.gl/tpsmEJ#status <https://goo.gl/tpsmEJ#status> for how > >> to communicate with syzbot. > >> syzbot can test patches for this bug, for details see: > >> https://goo.gl/tpsmEJ#testing-patches > >> <https://goo.gl/tpsmEJ#testing-patches> > >> -- > >> You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > >> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx <mailto:syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx>. > >> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/d71a274f-fdeb-4da1-898e-06f6944e04dan%40googlegroups.com <https://groups.google.com/d/msgid/syzkaller-bugs/d71a274f-fdeb-4da1-898e-06f6944e04dan%40googlegroups.com?utm_medium=email&utm_source=footer>. > > > > The reason of this memory leak is tty_ldisc_receive_buf() and tiocsti() > > can access the h4->rx_skb concurrently by calling > > hci_uart_tty_receive(), so the rx_skb be overwritten without > > deallocating. There used to be an spin_lock in hci_uart_tty_receive(), > > but it was removed by commit 7649ffaff1cfe(Bluetooth: Remove useless > > rx_lock spinlock). > > I don’t have that commit in my Linus’ tree. Where is it? > There is a typo in the git hash. It should be: 7649faff1cfe4 ("Bluetooth: Remove useless rx_lock spinlock"). > > The commit message claims that hci_uart_tty_receive() was only called by > > flush_to_ldisc(), but it seems incorrect. > > That seems to be a larger problem in the TTY layer if its contract with its users have changed. The tiocsti() function has an ancient comment which suggests that the documentation has always been wrong. * FIXME: may race normal receive processing regards, dan carpenter
