Re: [syzbot] [media?] KASAN: slab-use-after-free Read in dvb_frontend_release (3)

From: Hillf Danton

Date: Sat Feb 21 2026 - 08:40:47 EST


> Date: Mon, 16 Feb 2026 01:34:34 -0800 [thread overview]
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: c22e26bd0906 Merge tag 'landlock-7.0-rc1' of git://git.ker..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16bcf6e6580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=6428d17febdfb14e
> dashboard link: https://syzkaller.appspot.com/bug?extid=ae466a728017ec940b41
> compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15ce3652580000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1121515a580000

#syz test

--- x/drivers/media/dvb-core/dvb_frontend.c
+++ y/drivers/media/dvb-core/dvb_frontend.c
@@ -2911,6 +2911,7 @@ static int dvb_frontend_release(struct i
mb();
}

+ dvb_device_get(dvbdev);
ret = dvb_generic_release(inode, file);

if (dvbdev->users == -1) {
@@ -2930,6 +2931,7 @@ static int dvb_frontend_release(struct i
if (fe->ops.ts_bus_ctrl)
fe->ops.ts_bus_ctrl(fe, 0);
}
+ dvb_device_put(dvbdev);

dvb_frontend_put(fe);

--