cbcvebase.
CVE-2022-49441
published 2025-02-26

CVE-2022-49441: In the Linux kernel, the following vulnerability has been resolved: tty: fix deadlock caused by calling printk() under tty_port->lock pty_write() invokes…

PriorityP419medium5.5CVSS 3.1
AVLACLPRLUINSUCNINAH
EPSS
0.24%
14.7th percentile
In the Linux kernel, the following vulnerability has been resolved: tty: fix deadlock caused by calling printk() under tty_port->lock pty_write() invokes kmalloc() which may invoke a normal printk() to print failure message. This can cause a deadlock in the scenario reported by syz-bot below: CPU0 CPU1 CPU2 ---- ---- ---- lock(console_owner); lock(&port_lock_key); lock(&port->lock); lock(&port_lock_key); lock(&port->lock); lock(console_owner); As commit dbdda842fe96 ("printk: Add console owner and waiter logic to load balance console writes") said, such deadlock can be prevented by using printk_deferred() in kmalloc() (which is invoked in the section guarded by the port->lock). But there are too many printk() on the kmalloc() path, and kmalloc() can be called from anywhere, so changing printk() to printk_deferred() is too complicated and inelegant. Therefore, this patch chooses to specify __GFP_NOWARN to kmalloc(), so that printk() will not be called, and this deadlock problem can be avoided. Syzbot reported the following lockdep error: WARNING: possible circular locking dependency detected 5.4.143-00237-g08ccc19a-dirty #10 Not tainted syz-executor.4/29420 is trying to acquire lock: ffffffff8aedb2a0 (console_owner){....}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:1752 [inline] ffffffff8aedb2a0 (console_owner){....}-{0:0}, at: vprintk_emit+0x2ca/0x470 kernel/printk/printk.c:2023 but task is already holding lock: ffff8880119c9158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xf4/0x1f0 drivers/tty/pty.c:120 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&port->lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x35/0x50 kernel/locking/spinlock.c:159 tty_port_tty_get drivers/tty/tty_port.c:288 [inline] lock); tty_port_default_wakeup+0x1d/0xb0 drivers/tty/tty_port.c:47 serial8250_tx_chars+0x530/0xa80 drivers/tty/serial/8250/8250_por

Affected

33 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 5.18.5-1 (bookworm)linux 5.18.5-1 (bookworm)
linuxlinux
linuxlinux
linuxlinux
linuxlinux
linuxlinux>= 3.18.118 < 3.193.19
linuxlinux>= 4.14.60 < 4.14.2834.14.283
linuxlinux>= 4.17.12 < 4.184.18
linuxlinux>= 4.4.146 < 4.54.5
linuxlinux>= 4.9.117 < 4.9.3184.9.318
linuxlinux>= b6da31b2c07c46f2dcad1d86caa835227a16d9ff < 04ee31678c128a6cc7bb057ea189a8624ba5a31404ee31678c128a6cc7bb057ea189a8624ba5a314
linuxlinux>= b6da31b2c07c46f2dcad1d86caa835227a16d9ff < 3219ac364ac3d8d30771612a6010f1e0b7fa0a283219ac364ac3d8d30771612a6010f1e0b7fa0a28
linuxlinux>= b6da31b2c07c46f2dcad1d86caa835227a16d9ff < 9834b13e8b962caa28fbcf1f422dd82413da4ede9834b13e8b962caa28fbcf1f422dd82413da4ede
linuxlinux>= b6da31b2c07c46f2dcad1d86caa835227a16d9ff < 18ca0d55e8639b911df8aae1b47598b13f9acded18ca0d55e8639b911df8aae1b47598b13f9acded
linuxlinux>= b6da31b2c07c46f2dcad1d86caa835227a16d9ff < b3c974501d0c32258ae0e04e5cc3fb92383b40f6b3c974501d0c32258ae0e04e5cc3fb92383b40f6
linuxlinux>= b6da31b2c07c46f2dcad1d86caa835227a16d9ff < 0bcf44903ef4df742dcada86ccaedd25374ffb500bcf44903ef4df742dcada86ccaedd25374ffb50
linuxlinux>= b6da31b2c07c46f2dcad1d86caa835227a16d9ff < 6b9dbedbe3499fef862c4dff5217cf91f34e43b36b9dbedbe3499fef862c4dff5217cf91f34e43b3
linuxlinux>= d83904cb2eb2c4d937eaf15032214b0578f25099 < 4af21b12a60ed2d3642284f4f85b42d7dc6ac2464af21b12a60ed2d3642284f4f85b42d7dc6ac246
linuxlinux>= deb1feaad03a78b545c949e54582ae57b3c56982 < 4c253caf9264d2aa47ee806a87986dd8eb91a5d94c253caf9264d2aa47ee806a87986dd8eb91a5d9
linuxlinux_kernel>= 0 < 5.10.127-15.10.127-1
linuxlinux_kernel>= 0 < 5.18.5-15.18.5-1
linuxlinux_kernel>= 0 < 5.18.5-15.18.5-1
linuxlinux_kernel>= 0 < 5.18.5-15.18.5-1
linuxlinux_kernel>= 3.18.118 < 3.193.19
linuxlinux_kernel>= 4.14.60 < 4.14.2834.14.283

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
osv5.5MEDIUM
vendor_debian5.5MEDIUM
vendor_redhat5.5MEDIUM
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