linux-kernel - memory leak in fbcon_set

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Date:   Wed, 13 Jan 2021 02:38:15 -0800
From:   syzbot <syzbot+2f2c18881a450f22d1bf@...kaller.appspotmail.com>
To:     b.zolnierkie@...sung.com, daniel.vetter@...ll.ch,
        dri-devel@...ts.freedesktop.org, george.kennedy@...cle.com,
        gregkh@...uxfoundation.org, jirislaby@...nel.org,
        linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        syzkaller-bugs@...glegroups.com, yepeilin.cs@...il.com
Subject: memory leak in fbcon_set_font

Hello,

syzbot found the following issue on:

HEAD commit:    e609571b Merge tag 'nfs-for-5.11-2' of git://git.linux-nfs..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=165261e0d00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=850b6de5f8959443
dashboard link: https://syzkaller.appspot.com/bug?extid=2f2c18881a450f22d1bf
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16ab20c7500000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1008b770d00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2f2c18881a450f22d1bf@...kaller.appspotmail.com

BUG: memory leak
unreferenced object 0xffff88811813ea00 (size 512):
  comm "syz-executor939", pid 10246, jiffies 4294971847 (age 34.510s)
  hex dump (first 32 bytes):
    b0 55 1f 9b 00 00 00 00 00 01 00 00 06 00 00 00  .U..............
    11 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000062fad90>] kmalloc include/linux/slab.h:557 [inline]
    [<00000000062fad90>] fbcon_set_font+0x128/0x370 drivers/video/fbdev/core/fbcon.c:2454
    [<00000000ed2d1b1e>] con_font_set drivers/tty/vt/vt.c:4667 [inline]
    [<00000000ed2d1b1e>] con_font_op+0x497/0x740 drivers/tty/vt/vt.c:4711
    [<00000000fd6b18ad>] vt_io_ioctl drivers/tty/vt/vt_ioctl.c:596 [inline]
    [<00000000fd6b18ad>] vt_ioctl+0xeab/0x19d0 drivers/tty/vt/vt_ioctl.c:817
    [<00000000369331c6>] tty_ioctl+0x6c3/0xc40 drivers/tty/tty_io.c:2658
    [<00000000a092c047>] vfs_ioctl fs/ioctl.c:48 [inline]
    [<00000000a092c047>] __do_sys_ioctl fs/ioctl.c:753 [inline]
    [<00000000a092c047>] __se_sys_ioctl fs/ioctl.c:739 [inline]
    [<00000000a092c047>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:739
    [<00000000705a3959>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<00000000f35163f9>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88811813ea00 (size 512):
  comm "syz-executor939", pid 10246, jiffies 4294971847 (age 36.030s)
  hex dump (first 32 bytes):
    b0 55 1f 9b 00 00 00 00 00 01 00 00 06 00 00 00  .U..............
    11 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000062fad90>] kmalloc include/linux/slab.h:557 [inline]
    [<00000000062fad90>] fbcon_set_font+0x128/0x370 drivers/video/fbdev/core/fbcon.c:2454
    [<00000000ed2d1b1e>] con_font_set drivers/tty/vt/vt.c:4667 [inline]
    [<00000000ed2d1b1e>] con_font_op+0x497/0x740 drivers/tty/vt/vt.c:4711
    [<00000000fd6b18ad>] vt_io_ioctl drivers/tty/vt/vt_ioctl.c:596 [inline]
    [<00000000fd6b18ad>] vt_ioctl+0xeab/0x19d0 drivers/tty/vt/vt_ioctl.c:817
    [<00000000369331c6>] tty_ioctl+0x6c3/0xc40 drivers/tty/tty_io.c:2658
    [<00000000a092c047>] vfs_ioctl fs/ioctl.c:48 [inline]
    [<00000000a092c047>] __do_sys_ioctl fs/ioctl.c:753 [inline]
    [<00000000a092c047>] __se_sys_ioctl fs/ioctl.c:739 [inline]
    [<00000000a092c047>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:739
    [<00000000705a3959>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<00000000f35163f9>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88811813ea00 (size 512):
  comm "syz-executor939", pid 10246, jiffies 4294971847 (age 37.550s)
  hex dump (first 32 bytes):
    b0 55 1f 9b 00 00 00 00 00 01 00 00 06 00 00 00  .U..............
    11 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000062fad90>] kmalloc include/linux/slab.h:557 [inline]
    [<00000000062fad90>] fbcon_set_font+0x128/0x370 drivers/video/fbdev/core/fbcon.c:2454
    [<00000000ed2d1b1e>] con_font_set drivers/tty/vt/vt.c:4667 [inline]
    [<00000000ed2d1b1e>] con_font_op+0x497/0x740 drivers/tty/vt/vt.c:4711
    [<00000000fd6b18ad>] vt_io_ioctl drivers/tty/vt/vt_ioctl.c:596 [inline]
    [<00000000fd6b18ad>] vt_ioctl+0xeab/0x19d0 drivers/tty/vt/vt_ioctl.c:817
    [<00000000369331c6>] tty_ioctl+0x6c3/0xc40 drivers/tty/tty_io.c:2658
    [<00000000a092c047>] vfs_ioctl fs/ioctl.c:48 [inline]
    [<00000000a092c047>] __do_sys_ioctl fs/ioctl.c:753 [inline]
    [<00000000a092c047>] __se_sys_ioctl fs/ioctl.c:739 [inline]
    [<00000000a092c047>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:739
    [<00000000705a3959>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<00000000f35163f9>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88811813ea00 (size 512):
  comm "syz-executor939", pid 10246, jiffies 4294971847 (age 37.630s)
  hex dump (first 32 bytes):
    b0 55 1f 9b 00 00 00 00 00 01 00 00 06 00 00 00  .U..............
    11 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000062fad90>] kmalloc include/linux/slab.h:557 [inline]
    [<00000000062fad90>] fbcon_set_font+0x128/0x370 drivers/video/fbdev/core/fbcon.c:2454
    [<00000000ed2d1b1e>] con_font_set drivers/tty/vt/vt.c:4667 [inline]
    [<00000000ed2d1b1e>] con_font_op+0x497/0x740 drivers/tty/vt/vt.c:4711
    [<00000000fd6b18ad>] vt_io_ioctl drivers/tty/vt/vt_ioctl.c:596 [inline]
    [<00000000fd6b18ad>] vt_ioctl+0xeab/0x19d0 drivers/tty/vt/vt_ioctl.c:817
    [<00000000369331c6>] tty_ioctl+0x6c3/0xc40 drivers/tty/tty_io.c:2658
    [<00000000a092c047>] vfs_ioctl fs/ioctl.c:48 [inline]
    [<00000000a092c047>] __do_sys_ioctl fs/ioctl.c:753 [inline]
    [<00000000a092c047>] __se_sys_ioctl fs/ioctl.c:739 [inline]
    [<00000000a092c047>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:739
    [<00000000705a3959>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<00000000f35163f9>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88811813ea00 (size 512):
  comm "syz-executor939", pid 10246, jiffies 4294971847 (age 37.720s)
  hex dump (first 32 bytes):
    b0 55 1f 9b 00 00 00 00 00 01 00 00 06 00 00 00  .U..............
    11 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000062fad90>] kmalloc include/linux/slab.h:557 [inline]
    [<00000000062fad90>] fbcon_set_font+0x128/0x370 drivers/video/fbdev/core/fbcon.c:2454
    [<00000000ed2d1b1e>] con_font_set drivers/tty/vt/vt.c:4667 [inline]
    [<00000000ed2d1b1e>] con_font_op+0x497/0x740 drivers/tty/vt/vt.c:4711
    [<00000000fd6b18ad>] vt_io_ioctl drivers/tty/vt/vt_ioctl.c:596 [inline]
    [<00000000fd6b18ad>] vt_ioctl+0xeab/0x19d0 drivers/tty/vt/vt_ioctl.c:817
    [<00000000369331c6>] tty_ioctl+0x6c3/0xc40 drivers/tty/tty_io.c:2658
    [<00000000a092c047>] vfs_ioctl fs/ioctl.c:48 [inline]
    [<00000000a092c047>] __do_sys_ioctl fs/ioctl.c:753 [inline]
    [<00000000a092c047>] __se_sys_ioctl fs/ioctl.c:739 [inline]
    [<00000000a092c047>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:739
    [<00000000705a3959>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<00000000f35163f9>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88811813ea00 (size 512):
  comm "syz-executor939", pid 10246, jiffies 4294971847 (age 37.810s)
  hex dump (first 32 bytes):
    b0 55 1f 9b 00 00 00 00 00 01 00 00 06 00 00 00  .U..............
    11 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000062fad90>] kmalloc include/linux/slab.h:557 [inline]
    [<00000000062fad90>] fbcon_set_font+0x128/0x370 drivers/video/fbdev/core/fbcon.c:2454
    [<00000000ed2d1b1e>] con_font_set drivers/tty/vt/vt.c:4667 [inline]
    [<00000000ed2d1b1e>] con_font_op+0x497/0x740 drivers/tty/vt/vt.c:4711
    [<00000000fd6b18ad>] vt_io_ioctl drivers/tty/vt/vt_ioctl.c:596 [inline]
    [<00000000fd6b18ad>] vt_ioctl+0xeab/0x19d0 drivers/tty/vt/vt_ioctl.c:817
    [<00000000369331c6>] tty_ioctl+0x6c3/0xc40 drivers/tty/tty_io.c:2658
    [<00000000a092c047>] vfs_ioctl fs/ioctl.c:48 [inline]
    [<00000000a092c047>] __do_sys_ioctl fs/ioctl.c:753 [inline]
    [<00000000a092c047>] __se_sys_ioctl fs/ioctl.c:739 [inline]
    [<00000000a092c047>] __x64_sys_ioctl+0xfc/0x140 fs/ioctl.c:739
    [<00000000705a3959>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<00000000f35163f9>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory
executing program
write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory
write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory
write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory
executing program
write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory
write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory
write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory
write to /proc/sys/kernel/hung_task_check_interval_secs failed: No such file or directory
write to /proc/sys/kernel/softlockup_all_cpu_backtrace failed: No such file or directory


---
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