[syzbot] memory leak in gsmld_ioctl

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b229b6ca5abb Merge tag 'perf-tools-fixes-for-v6.1-2022-10-..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14f684ee880000
kernel config: https://syzkaller.appspot.com/x/.config?x=8e0c1dbca40c1f1d
dashboard link: https://syzkaller.appspot.com/bug?extid=6e3e8f30f269f5028e5d
compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12c41d22880000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1357247a880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/cf67b1049a03/disk-b229b6ca.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3f2fbf5dbb8c/vmlinux-b229b6ca.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7ff8681ade50/bzImage-b229b6ca.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6e3e8f...@syzkaller.appspotmail.com

BUG: memory leak
unreferenced object 0xffff88810ec09400 (size 1024):
comm "syz-executor252", pid 3630, jiffies 4294960211 (age 24.300s)
hex dump (first 32 bytes):
00 bc c0 0e 81 88 ff ff 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:
[<ffffffff814cfe70>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
[<ffffffff826196b7>] kmalloc include/linux/slab.h:576 [inline]
[<ffffffff826196b7>] kzalloc include/linux/slab.h:712 [inline]
[<ffffffff826196b7>] gsm_dlci_alloc+0x27/0x180 drivers/tty/n_gsm.c:2060
[<ffffffff8261ea0b>] gsm_activate_mux drivers/tty/n_gsm.c:2534 [inline]
[<ffffffff8261ea0b>] gsm_config drivers/tty/n_gsm.c:2776 [inline]
[<ffffffff8261ea0b>] gsmld_ioctl+0x45b/0x750 drivers/tty/n_gsm.c:3113
[<ffffffff826063f3>] tty_ioctl+0x733/0xbe0 drivers/tty/tty_io.c:2780
[<ffffffff81602b2c>] vfs_ioctl fs/ioctl.c:51 [inline]
[<ffffffff81602b2c>] __do_sys_ioctl fs/ioctl.c:870 [inline]
[<ffffffff81602b2c>] __se_sys_ioctl fs/ioctl.c:856 [inline]
[<ffffffff81602b2c>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:856
[<ffffffff84608025>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84608025>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

BUG: memory leak
unreferenced object 0xffff88810ec09400 (size 1024):
comm "syz-executor252", pid 3630, jiffies 4294960211 (age 25.470s)
hex dump (first 32 bytes):
00 bc c0 0e 81 88 ff ff 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:
[<ffffffff814cfe70>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
[<ffffffff826196b7>] kmalloc include/linux/slab.h:576 [inline]
[<ffffffff826196b7>] kzalloc include/linux/slab.h:712 [inline]
[<ffffffff826196b7>] gsm_dlci_alloc+0x27/0x180 drivers/tty/n_gsm.c:2060
[<ffffffff8261ea0b>] gsm_activate_mux drivers/tty/n_gsm.c:2534 [inline]
[<ffffffff8261ea0b>] gsm_config drivers/tty/n_gsm.c:2776 [inline]
[<ffffffff8261ea0b>] gsmld_ioctl+0x45b/0x750 drivers/tty/n_gsm.c:3113
[<ffffffff826063f3>] tty_ioctl+0x733/0xbe0 drivers/tty/tty_io.c:2780
[<ffffffff81602b2c>] vfs_ioctl fs/ioctl.c:51 [inline]
[<ffffffff81602b2c>] __do_sys_ioctl fs/ioctl.c:870 [inline]
[<ffffffff81602b2c>] __se_sys_ioctl fs/ioctl.c:856 [inline]
[<ffffffff81602b2c>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:856
[<ffffffff84608025>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84608025>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

BUG: memory leak
unreferenced object 0xffff88810ec09400 (size 1024):
comm "syz-executor252", pid 3630, jiffies 4294960211 (age 28.890s)
hex dump (first 32 bytes):
00 bc c0 0e 81 88 ff ff 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:
[<ffffffff814cfe70>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
[<ffffffff826196b7>] kmalloc include/linux/slab.h:576 [inline]
[<ffffffff826196b7>] kzalloc include/linux/slab.h:712 [inline]
[<ffffffff826196b7>] gsm_dlci_alloc+0x27/0x180 drivers/tty/n_gsm.c:2060
[<ffffffff8261ea0b>] gsm_activate_mux drivers/tty/n_gsm.c:2534 [inline]
[<ffffffff8261ea0b>] gsm_config drivers/tty/n_gsm.c:2776 [inline]
[<ffffffff8261ea0b>] gsmld_ioctl+0x45b/0x750 drivers/tty/n_gsm.c:3113
[<ffffffff826063f3>] tty_ioctl+0x733/0xbe0 drivers/tty/tty_io.c:2780
[<ffffffff81602b2c>] vfs_ioctl fs/ioctl.c:51 [inline]
[<ffffffff81602b2c>] __do_sys_ioctl fs/ioctl.c:870 [inline]
[<ffffffff81602b2c>] __se_sys_ioctl fs/ioctl.c:856 [inline]
[<ffffffff81602b2c>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:856
[<ffffffff84608025>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84608025>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

BUG: memory leak
unreferenced object 0xffff88810ec09400 (size 1024):
comm "syz-executor252", pid 3630, jiffies 4294960211 (age 28.920s)
hex dump (first 32 bytes):
00 bc c0 0e 81 88 ff ff 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:
[<ffffffff814cfe70>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
[<ffffffff826196b7>] kmalloc include/linux/slab.h:576 [inline]
[<ffffffff826196b7>] kzalloc include/linux/slab.h:712 [inline]
[<ffffffff826196b7>] gsm_dlci_alloc+0x27/0x180 drivers/tty/n_gsm.c:2060
[<ffffffff8261ea0b>] gsm_activate_mux drivers/tty/n_gsm.c:2534 [inline]
[<ffffffff8261ea0b>] gsm_config drivers/tty/n_gsm.c:2776 [inline]
[<ffffffff8261ea0b>] gsmld_ioctl+0x45b/0x750 drivers/tty/n_gsm.c:3113
[<ffffffff826063f3>] tty_ioctl+0x733/0xbe0 drivers/tty/tty_io.c:2780
[<ffffffff81602b2c>] vfs_ioctl fs/ioctl.c:51 [inline]
[<ffffffff81602b2c>] __do_sys_ioctl fs/ioctl.c:870 [inline]
[<ffffffff81602b2c>] __se_sys_ioctl fs/ioctl.c:856 [inline]
[<ffffffff81602b2c>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:856
[<ffffffff84608025>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84608025>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

BUG: memory leak
unreferenced object 0xffff88810ec09400 (size 1024):
comm "syz-executor252", pid 3630, jiffies 4294960211 (age 28.960s)
hex dump (first 32 bytes):
00 bc c0 0e 81 88 ff ff 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:
[<ffffffff814cfe70>] kmalloc_trace+0x20/0x90 mm/slab_common.c:1046
[<ffffffff826196b7>] kmalloc include/linux/slab.h:576 [inline]
[<ffffffff826196b7>] kzalloc include/linux/slab.h:712 [inline]
[<ffffffff826196b7>] gsm_dlci_alloc+0x27/0x180 drivers/tty/n_gsm.c:2060
[<ffffffff8261ea0b>] gsm_activate_mux drivers/tty/n_gsm.c:2534 [inline]
[<ffffffff8261ea0b>] gsm_config drivers/tty/n_gsm.c:2776 [inline]
[<ffffffff8261ea0b>] gsmld_ioctl+0x45b/0x750 drivers/tty/n_gsm.c:3113
[<ffffffff826063f3>] tty_ioctl+0x733/0xbe0 drivers/tty/tty_io.c:2780
[<ffffffff81602b2c>] vfs_ioctl fs/ioctl.c:51 [inline]
[<ffffffff81602b2c>] __do_sys_ioctl fs/ioctl.c:870 [inline]
[<ffffffff81602b2c>] __se_sys_ioctl fs/ioctl.c:856 [inline]
[<ffffffff81602b2c>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:856
[<ffffffff84608025>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff84608025>] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
[<ffffffff84800087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

executing program
executing program
executing program


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