linux/drivers/tty, branch v6.0

serial: sifive: enable clocks for UART when probed

2022-09-22T14:38:18Z

When the PWM driver was changed to disable clocks if no PWMs are enabled, it ended up also disabling the shared parent with the UART, since the UART doesn't do any clock enablement on its own. To avoid these surprises, switch to clk_get_enabled(). Fixes: ace41d7564e655 ("pwm: sifive: Ensure the clk is enabled exactly once per running PWM") Cc: stable Cc: Uwe Kleine-König Cc: Emil Renner Berthing Cc: Palmer Dabbelt Cc: Paul Walmsley Reviewed-by: Palmer Dabbelt Reviewed-by: Uwe Kleine-König Acked-by: Palmer Dabbelt Signed-off-by: Olof Johansson Link: https://lore.kernel.org/r/20220920160017.7315-1-olof@lixom.net Signed-off-by: Greg Kroah-Hartman

serial: 8250: omap: Use serial8250_em485_supported

2022-09-22T14:38:06Z

8250_omap uses em485, fill in rs485_supported accordingly. This makes RS485 work with 8250_omap again, which was broken with the introduction of the RS485 config sanitization. Fixes: be2e2cb1d2819 ("serial: Sanitize rs485_struct") Reviewed-by: Ilpo Järvinen Signed-off-by: Matthias Schiffer Link: https://lore.kernel.org/r/20220916110955.161099-1-matthias.schiffer@ew.tq-group.com Signed-off-by: Greg Kroah-Hartman

serial: fsl_lpuart: Reset prior to registration

2022-09-22T14:37:59Z

Since commit bd5305dcabbc ("tty: serial: fsl_lpuart: do software reset for imx7ulp and imx8qxp"), certain i.MX UARTs are reset after they've already been registered. Register state may thus be clobbered after user space has begun to open and access the UART. Avoid by performing the reset prior to registration. Fixes: bd5305dcabbc ("tty: serial: fsl_lpuart: do software reset for imx7ulp and imx8qxp") Cc: stable@vger.kernel.org # v5.15+ Cc: Fugang Duan Cc: Sherry Sun Reviewed-by: Ilpo Järvinen Signed-off-by: Lukas Wunner Link: https://lore.kernel.org/r/72fb646c1b0b11c989850c55f52f9ff343d1b2fa.1662884345.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman

serial: tegra-tcu: Use uart_xmit_advance(), fixes icount.tx accounting

2022-09-07T14:40:29Z

Tx'ing does not correctly account Tx'ed characters into icount.tx. Using uart_xmit_advance() fixes the problem. Fixes: 2d908b38d409 ("serial: Add Tegra Combined UART driver") Cc: # serial: Create uart_xmit_advance() Reviewed-by: Andy Shevchenko Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220901143934.8850-4-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

serial: tegra: Use uart_xmit_advance(), fixes icount.tx accounting

2022-09-07T14:40:21Z

DMA complete & stop paths did not correctly account Tx'ed characters into icount.tx. Using uart_xmit_advance() fixes the problem. Fixes: e9ea096dd225 ("serial: tegra: add serial driver") Cc: # serial: Create uart_xmit_advance() Reviewed-by: Andy Shevchenko Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20220901143934.8850-3-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

tty: n_gsm: avoid call of sleeping functions from atomic context

2022-08-30T12:40:17Z

Syzkaller reports the following problem: BUG: sleeping function called from invalid context at kernel/printk/printk.c:2347 in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 1105, name: syz-executor423 3 locks held by syz-executor423/1105: #0: ffff8881468b9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x90 drivers/tty/tty_ldisc.c:266 #1: ffff8881468b9130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:952 [inline] #1: ffff8881468b9130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:975 [inline] #1: ffff8881468b9130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write.constprop.0+0x2a8/0x8e0 drivers/tty/tty_io.c:1118 #2: ffff88801b06c398 (&gsm->tx_lock){....}-{2:2}, at: gsmld_write+0x5e/0x150 drivers/tty/n_gsm.c:2717 irq event stamp: 3482 hardirqs last enabled at (3481): [] __get_reqs_available+0x143/0x2f0 fs/aio.c:946 hardirqs last disabled at (3482): [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] hardirqs last disabled at (3482): [] _raw_spin_lock_irqsave+0x52/0x60 kernel/locking/spinlock.c:159 softirqs last enabled at (3408): [] asm_call_irq_on_stack+0x12/0x20 softirqs last disabled at (3401): [] asm_call_irq_on_stack+0x12/0x20 Preemption disabled at: [<0000000000000000>] 0x0 CPU: 2 PID: 1105 Comm: syz-executor423 Not tainted 5.10.137-syzkaller #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x167 lib/dump_stack.c:118 ___might_sleep.cold+0x1e8/0x22e kernel/sched/core.c:7304 console_lock+0x19/0x80 kernel/printk/printk.c:2347 do_con_write+0x113/0x1de0 drivers/tty/vt/vt.c:2909 con_write+0x22/0xc0 drivers/tty/vt/vt.c:3296 gsmld_write+0xd0/0x150 drivers/tty/n_gsm.c:2720 do_tty_write drivers/tty/tty_io.c:1028 [inline] file_tty_write.constprop.0+0x502/0x8e0 drivers/tty/tty_io.c:1118 call_write_iter include/linux/fs.h:1903 [inline] aio_write+0x355/0x7b0 fs/aio.c:1580 __io_submit_one fs/aio.c:1952 [inline] io_submit_one+0xf45/0x1a90 fs/aio.c:1999 __do_sys_io_submit fs/aio.c:2058 [inline] __se_sys_io_submit fs/aio.c:2028 [inline] __x64_sys_io_submit+0x18c/0x2f0 fs/aio.c:2028 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xc6 The problem happens in the following control flow: gsmld_write(...) spin_lock_irqsave(&gsm->tx_lock, flags) // taken a spinlock on TX data con_write(...) do_con_write(...) console_lock() might_sleep() // -> bug As far as console_lock() might sleep it should not be called with spinlock held. The patch replaces tx_lock spinlock with mutex in order to avoid the problem. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Fixes: 32dd59f96924 ("tty: n_gsm: fix race condition in gsmld_write()") Cc: stable Signed-off-by: Fedor Pchelkin Signed-off-by: Alexey Khoroshilov Link: https://lore.kernel.org/r/20220829131640.69254-3-pchelkin@ispras.ru Signed-off-by: Greg Kroah-Hartman

tty: n_gsm: replace kicktimer with delayed_work

2022-08-30T12:37:40Z

A kick_timer timer_list is replaced with kick_timeout delayed_work to be able to synchronize with mutexes as a prerequisite for the introduction of tx_mutex. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Fixes: c568f7086c6e ("tty: n_gsm: fix missing timer to handle stalled links") Cc: stable Reviewed-by: Jiri Slaby Suggested-by: Hillf Danton Signed-off-by: Fedor Pchelkin Signed-off-by: Alexey Khoroshilov Link: https://lore.kernel.org/r/20220829131640.69254-2-pchelkin@ispras.ru Signed-off-by: Greg Kroah-Hartman

tty: n_gsm: initialize more members at gsm_alloc_mux()

2022-08-30T12:35:04Z

syzbot is reporting use of uninitialized spinlock at gsmld_write() [1], for commit 32dd59f96924f45e ("tty: n_gsm: fix race condition in gsmld_write()") allows accessing gsm->tx_lock before gsm_activate_mux() initializes it. Since object initialization should be done right after allocation in order to avoid accessing uninitialized memory, move initialization of timer/work/waitqueue/spinlock from gsmld_open()/gsm_activate_mux() to gsm_alloc_mux(). Link: https://syzkaller.appspot.com/bug?extid=cf155def4e717db68a12 [1] Fixes: 32dd59f96924f45e ("tty: n_gsm: fix race condition in gsmld_write()") Reported-by: syzbot Tested-by: syzbot Cc: stable Acked-by: Jiri Slaby Signed-off-by: Tetsuo Handa Link: https://lore.kernel.org/r/2110618e-57f0-c1ce-b2ad-b6cacef3f60e@I-love.SAKURA.ne.jp Signed-off-by: Greg Kroah-Hartman

tty: n_gsm: add sanity check for gsm->receive in gsm_receive_buf()

2022-08-30T12:34:36Z

A null pointer dereference can happen when attempting to access the "gsm->receive()" function in gsmld_receive_buf(). Currently, the code assumes that gsm->recieve is only called after MUX activation. Since the gsmld_receive_buf() function can be accessed without the need to initialize the MUX, the gsm->receive() function will not be set and a NULL pointer dereference will occur. Fix this by avoiding the call to "gsm->receive()" in case the function is not initialized by adding a sanity check. Call Trace: gsmld_receive_buf+0x1c2/0x2f0 drivers/tty/n_gsm.c:2861 tiocsti drivers/tty/tty_io.c:2293 [inline] tty_ioctl+0xa75/0x15d0 drivers/tty/tty_io.c:2692 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl fs/ioctl.c:856 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Link: https://syzkaller.appspot.com/bug?id=bdf035c61447f8c6e0e6920315d577cb5cc35ac5 Fixes: 01aecd917114 ("tty: n_gsm: fix tty registration before control channel open") Cc: stable Reported-and-tested-by: syzbot+e3563f0c94e188366dbb@syzkaller.appspotmail.com Signed-off-by: Mazin Al Haddad Link: https://lore.kernel.org/r/20220814015211.84180-1-mazinalhaddad05@gmail.com Signed-off-by: Greg Kroah-Hartman

tty: serial: atmel: Preserve previous USART mode if RS485 disabled

2022-08-30T12:33:08Z

Whenever the atmel_rs485_config() driver method would be called, the USART mode is reset to normal mode before even checking if RS485 flag is set, thus resulting in losing the previous USART mode in the case where the checking fails. Some tools, such as `linux-serial-test`, lead to the driver calling this method when doing the setup of the serial port: after setting the port mode (Hardware Flow Control, Normal Mode, RS485 Mode, etc.), `linux-serial-test` tries to enable/disable RS485 depending on the commandline arguments that were passed. Example of how this issue could reveal itself: When doing a serial communication with Hardware Flow Control through `linux-serial-test`, the tool would lead to the driver roughly doing the following: - set the corresponding bit to 1 (ATMEL_US_USMODE_HWHS bit in the ATMEL_US_MR register) through the atmel_set_termios() to enable Hardware Flow Control - disable RS485 through the atmel_config_rs485() method Thus, when the latter is called, the mode will be reset and the previously set bit is unset, leaving USART in normal mode instead of the expected Hardware Flow Control mode. This fix ensures that this reset is only done if the checking for RS485 succeeds and that the previous mode is preserved otherwise. Fixes: e8faff7330a35 ("ARM: 6092/1: atmel_serial: support for RS485 communications") Cc: stable Reviewed-by: Ilpo Järvinen Signed-off-by: Sergiu Moga Link: https://lore.kernel.org/r/20220824142902.502596-1-sergiu.moga@microchip.com Signed-off-by: Greg Kroah-Hartman