From 347a28b586802d09604a149c1a1f6de5dccbe6fa Mon Sep 17 00:00:00 2001 From: Anders Roxell Date: Tue, 30 Oct 2018 12:35:45 +0100 Subject: writeback: don't decrement wb->refcnt if !wb->bdi This happened while running in qemu-system-aarch64, the AMBA PL011 UART driver when enabling CONFIG_DEBUG_TEST_DRIVER_REMOVE. arch_initcall(pl011_init) came before subsys_initcall(default_bdi_init), devtmpfs' handle_remove() crashes because the reference count is a NULL pointer only because wb->bdi hasn't been initialized yet. Rework so that wb_put have an extra check if wb->bdi before decrement wb->refcnt and also add a WARN_ON_ONCE to get a warning if it happens again in other drivers. Fixes: 52ebea749aae ("writeback: make backing_dev_info host cgroup-specific bdi_writebacks") Co-developed-by: Arnd Bergmann Signed-off-by: Arnd Bergmann Signed-off-by: Anders Roxell Signed-off-by: Greg Kroah-Hartman --- include/linux/backing-dev-defs.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include') diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h index 9a6bc0951cfa..c31157135598 100644 --- a/include/linux/backing-dev-defs.h +++ b/include/linux/backing-dev-defs.h @@ -258,6 +258,14 @@ static inline void wb_get(struct bdi_writeback *wb) */ static inline void wb_put(struct bdi_writeback *wb) { + if (WARN_ON_ONCE(!wb->bdi)) { + /* + * A driver bug might cause a file to be removed before bdi was + * initialized. + */ + return; + } + if (wb != &wb->bdi->wb) percpu_ref_put(&wb->refcnt); } -- cgit v1.2.3 From d6e1935819db0c91ce4a5af82466f3ab50d17346 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Tue, 30 Oct 2018 15:11:04 -0700 Subject: serial: core: Allow processing sysrq at port unlock time Right now serial drivers process sysrq keys deep in their character receiving code. This means that they've already grabbed their port->lock spinlock. This can end up getting in the way if we've go to do serial stuff (especially kgdb) in response to the sysrq. Serial drivers have various hacks in them to handle this. Looking at '8250_port.c' you can see that the console_write() skips locking if we're in the sysrq handler. Looking at 'msm_serial.c' you can see that the port lock is dropped around uart_handle_sysrq_char(). It turns out that these hacks aren't exactly perfect. If you have lockdep turned on and use something like the 8250_port hack you'll get a splat that looks like: WARNING: possible circular locking dependency detected [...] is trying to acquire lock: ... (console_owner){-.-.}, at: console_unlock+0x2e0/0x5e4 but task is already holding lock: ... (&port_lock_key){-.-.}, at: serial8250_handle_irq+0x30/0xe4 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&port_lock_key){-.-.}: _raw_spin_lock_irqsave+0x58/0x70 serial8250_console_write+0xa8/0x250 univ8250_console_write+0x40/0x4c console_unlock+0x528/0x5e4 register_console+0x2c4/0x3b0 uart_add_one_port+0x350/0x478 serial8250_register_8250_port+0x350/0x3a8 dw8250_probe+0x67c/0x754 platform_drv_probe+0x58/0xa4 really_probe+0x150/0x294 driver_probe_device+0xac/0xe8 __driver_attach+0x98/0xd0 bus_for_each_dev+0x84/0xc8 driver_attach+0x2c/0x34 bus_add_driver+0xf0/0x1ec driver_register+0xb4/0x100 __platform_driver_register+0x60/0x6c dw8250_platform_driver_init+0x20/0x28 ... -> #0 (console_owner){-.-.}: lock_acquire+0x1e8/0x214 console_unlock+0x35c/0x5e4 vprintk_emit+0x230/0x274 vprintk_default+0x7c/0x84 vprintk_func+0x190/0x1bc printk+0x80/0xa0 __handle_sysrq+0x104/0x21c handle_sysrq+0x30/0x3c serial8250_read_char+0x15c/0x18c serial8250_rx_chars+0x34/0x74 serial8250_handle_irq+0x9c/0xe4 dw8250_handle_irq+0x98/0xcc serial8250_interrupt+0x50/0xe8 ... other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&port_lock_key); lock(console_owner); lock(&port_lock_key); lock(console_owner); *** DEADLOCK *** The hack used in 'msm_serial.c' doesn't cause the above splats but it seems a bit ugly to unlock / lock our spinlock deep in our irq handler. It seems like we could defer processing the sysrq until the end of the interrupt handler right after we've unlocked the port. With this scheme if a whole batch of sysrq characters comes in one irq then we won't handle them all, but that seems like it should be a fine compromise. Signed-off-by: Douglas Anderson Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_core.h | 37 ++++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 047fa67d039b..78de9d929762 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -175,6 +175,7 @@ struct uart_port { struct console *cons; /* struct console, if any */ #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ) unsigned long sysrq; /* sysrq timeout */ + unsigned int sysrq_ch; /* char for sysrq */ #endif /* flags must be updated while holding port mutex */ @@ -485,8 +486,42 @@ uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) } return 0; } +static inline int +uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) +{ + if (port->sysrq) { + if (ch && time_before(jiffies, port->sysrq)) { + port->sysrq_ch = ch; + port->sysrq = 0; + return 1; + } + port->sysrq = 0; + } + return 0; +} +static inline void +uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags) +{ + int sysrq_ch; + + sysrq_ch = port->sysrq_ch; + port->sysrq_ch = 0; + + spin_unlock_irqrestore(&port->lock, irqflags); + + if (sysrq_ch) + handle_sysrq(sysrq_ch); +} #else -#define uart_handle_sysrq_char(port,ch) ({ (void)port; 0; }) +static inline int +uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; } +static inline int +uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; } +static inline void +uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags) +{ + spin_unlock_irqrestore(&port->lock, irqflags); +} #endif /* -- cgit v1.2.3 From 3e6f88068314ffdba61a19f48ab0118f50424348 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Tue, 30 Oct 2018 15:11:06 -0700 Subject: serial: core: Include console.h from serial_core.h In the static inline function uart_handle_break() in serial_core.h we dereference port->cons. That gives an error unless console.h is also included. This error hasn't shown up till now because everyone who has defined SUPPORT_SYSRQ has also included console.h, but it's a bit ugly to make this requirement. Let's make the include explicit. Signed-off-by: Douglas Anderson Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_core.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 78de9d929762..5fe2b037e833 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -22,6 +22,7 @@ #include #include +#include #include #include #include -- cgit v1.2.3 From d491324f966518fbd3f4c627a3e9766d018a4eef Mon Sep 17 00:00:00 2001 From: Songjun Wu Date: Thu, 22 Nov 2018 15:47:35 +0800 Subject: include: Add lantiq.h in include/linux/ In some existing lantiq driver, the C codes include lantiq_soc.h header file directly. ./arch/mips/include/asm/mach-lantiq/falcon/lantiq_soc.h ./arch/mips/include/asm/mach-lantiq/xway/lantiq_soc.h Those drivers need to be extended to support more platform. lantiq.h is added in include/linux/ to make it globally available and provides some wrapper codes. Signed-off-by: Songjun Wu Signed-off-by: Greg Kroah-Hartman --- include/linux/lantiq.h | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) create mode 100644 include/linux/lantiq.h (limited to 'include') diff --git a/include/linux/lantiq.h b/include/linux/lantiq.h new file mode 100644 index 000000000000..67921169d84d --- /dev/null +++ b/include/linux/lantiq.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __LINUX_LANTIQ_H +#define __LINUX_LANTIQ_H + +#ifdef CONFIG_LANTIQ +#include +#else + +#ifndef LTQ_EARLY_ASC +#define LTQ_EARLY_ASC 0 +#endif + +#ifndef CPHYSADDR +#define CPHYSADDR(a) 0 +#endif + +static inline struct clk *clk_get_fpi(void) +{ + return NULL; +} +#endif /* CONFIG_LANTIQ */ +#endif /* __LINUX_LANTIQ_H */ -- cgit v1.2.3 From 70d188041e6f1f92004f1d5d7ddfd5013273b7a5 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 14 Nov 2018 16:09:03 +0100 Subject: serdev: make synchronous write helper interruptible Allow the synchronous serdev_device_write() helper to be interrupted. This is useful for cases where I/O is performed on behalf of user space and we don't want to block indefinitely when using flow control. Signed-off-by: Johan Hovold Reviewed-by: Rob Herring Signed-off-by: Greg Kroah-Hartman --- include/linux/serdev.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/serdev.h b/include/linux/serdev.h index f153b2c7f0cd..070bf4e92df7 100644 --- a/include/linux/serdev.h +++ b/include/linux/serdev.h @@ -210,7 +210,7 @@ void serdev_device_wait_until_sent(struct serdev_device *, long); int serdev_device_get_tiocm(struct serdev_device *); int serdev_device_set_tiocm(struct serdev_device *, int, int); void serdev_device_write_wakeup(struct serdev_device *); -int serdev_device_write(struct serdev_device *, const unsigned char *, size_t, unsigned long); +int serdev_device_write(struct serdev_device *, const unsigned char *, size_t, long); void serdev_device_write_flush(struct serdev_device *); int serdev_device_write_room(struct serdev_device *); -- cgit v1.2.3 From 77cab92a2cb15bcbdd7be0af773799e92d6a8546 Mon Sep 17 00:00:00 2001 From: Rafael Aquini Date: Thu, 29 Nov 2018 10:08:17 -0500 Subject: sysctl: clean up nr_pdflush_threads leftover nr_pdflush_threads has been long deprecated and removed, but a remnant of its glorious past is still around in CTL_VM names enum. This patch is a minor clean-up to that case. Reviewed-by: William Kucharski Signed-off-by: Rafael Aquini Signed-off-by: Greg Kroah-Hartman --- include/uapi/linux/sysctl.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h index d71013fffaf6..9df59925ed55 100644 --- a/include/uapi/linux/sysctl.h +++ b/include/uapi/linux/sysctl.h @@ -161,7 +161,7 @@ enum enum { VM_UNUSED1=1, /* was: struct: Set vm swapping control */ - VM_UNUSED2=2, /* was; int: Linear or sqrt() swapout for hogs */ + VM_UNUSED2=2, /* was: int: Linear or sqrt() swapout for hogs */ VM_UNUSED3=3, /* was: struct: Set free page thresholds */ VM_UNUSED4=4, /* Spare */ VM_OVERCOMMIT_MEMORY=5, /* Turn off the virtual memory safety limit */ @@ -174,7 +174,7 @@ enum VM_DIRTY_RATIO=12, /* dirty_ratio */ VM_DIRTY_WB_CS=13, /* dirty_writeback_centisecs */ VM_DIRTY_EXPIRE_CS=14, /* dirty_expire_centisecs */ - VM_NR_PDFLUSH_THREADS=15, /* nr_pdflush_threads */ + VM_UNUSED15=15, /* was: int: nr_pdflush_threads */ VM_OVERCOMMIT_RATIO=16, /* percent of RAM to allow overcommit in */ VM_PAGEBUF=17, /* struct: Control pagebuf parameters */ VM_HUGETLB_PAGES=18, /* int: Number of available Huge Pages */ -- cgit v1.2.3 From c96cf923a98d1b094df9f0cf97a83e118817e31b Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Thu, 1 Nov 2018 00:24:48 +0000 Subject: tty: Don't block on IO when ldisc change is pending There might be situations where tty_ldisc_lock() has blocked, but there is already IO on tty and it prevents line discipline changes. It might theoretically turn into dead-lock. Basically, provide more priority to pending tty_ldisc_lock() than to servicing reads/writes over tty. User-visible issue was reported by Mikulas where on pa-risc with Debian 5 reboot took either 80 seconds, 3 minutes or 3:25 after proper locking in tty_reopen(). Cc: Jiri Slaby Reported-by: Mikulas Patocka Signed-off-by: Dmitry Safonov Signed-off-by: Greg Kroah-Hartman --- include/linux/tty.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include') diff --git a/include/linux/tty.h b/include/linux/tty.h index 414db2bce715..80ae5528ef8e 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -366,6 +366,7 @@ struct tty_file_private { #define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */ #define TTY_HUPPED 18 /* Post driver->hangup() */ #define TTY_HUPPING 19 /* Hangup in progress */ +#define TTY_LDISC_CHANGING 20 /* Change pending - non-block IO */ #define TTY_LDISC_HALTED 22 /* Line discipline is halted */ /* Values for tty->flow_change */ @@ -383,6 +384,12 @@ static inline void tty_set_flow_change(struct tty_struct *tty, int val) smp_mb(); } +static inline bool tty_io_nonblock(struct tty_struct *tty, struct file *file) +{ + return file->f_flags & O_NONBLOCK || + test_bit(TTY_LDISC_CHANGING, &tty->flags); +} + static inline bool tty_io_error(struct tty_struct *tty) { return test_bit(TTY_IO_ERROR, &tty->flags); -- cgit v1.2.3 From 1528e40fd7d382e9668d3a1876a83d30bb04d554 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Fri, 7 Dec 2018 12:56:04 +0100 Subject: Revert "sysctl: clean up nr_pdflush_threads leftover" This reverts commit 77cab92a2cb15bcbdd7be0af773799e92d6a8546. Heiko reports that this breaks building of strace, which isn't ok. Reported-by: Heiko Carstens Cc: Rafael Aquini Cc: William Kucharski Signed-off-by: Greg Kroah-Hartman --- include/uapi/linux/sysctl.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h index 9df59925ed55..d71013fffaf6 100644 --- a/include/uapi/linux/sysctl.h +++ b/include/uapi/linux/sysctl.h @@ -161,7 +161,7 @@ enum enum { VM_UNUSED1=1, /* was: struct: Set vm swapping control */ - VM_UNUSED2=2, /* was: int: Linear or sqrt() swapout for hogs */ + VM_UNUSED2=2, /* was; int: Linear or sqrt() swapout for hogs */ VM_UNUSED3=3, /* was: struct: Set free page thresholds */ VM_UNUSED4=4, /* Spare */ VM_OVERCOMMIT_MEMORY=5, /* Turn off the virtual memory safety limit */ @@ -174,7 +174,7 @@ enum VM_DIRTY_RATIO=12, /* dirty_ratio */ VM_DIRTY_WB_CS=13, /* dirty_writeback_centisecs */ VM_DIRTY_EXPIRE_CS=14, /* dirty_expire_centisecs */ - VM_UNUSED15=15, /* was: int: nr_pdflush_threads */ + VM_NR_PDFLUSH_THREADS=15, /* nr_pdflush_threads */ VM_OVERCOMMIT_RATIO=16, /* percent of RAM to allow overcommit in */ VM_PAGEBUF=17, /* struct: Control pagebuf parameters */ VM_HUGETLB_PAGES=18, /* int: Number of available Huge Pages */ -- cgit v1.2.3 From 6d7f677a2afa1c82d7fc7af7f9159cbffd5dc010 Mon Sep 17 00:00:00 2001 From: Darwin Dingel Date: Mon, 10 Dec 2018 11:29:09 +1300 Subject: serial: 8250: Rate limit serial port rx interrupts during input overruns When a serial port gets faulty or gets flooded with inputs, its interrupt handler starts to work double time to get the characters to the workqueue for the tty layer to handle them. When this busy time on the serial/tty subsystem happens during boot, where it is also busy on the userspace trying to initialise, some processes can continuously get preempted and will be on hold until the interrupts subside. The fix is to backoff on processing received characters for a specified amount of time when an input overrun is seen (received a new character before the previous one is processed). This only stops receive and will continue to transmit characters to serial port. After the backoff period is done, it receive will be re-enabled. This is optional and will only be enabled by setting 'overrun-throttle-ms' in the dts. Signed-off-by: Darwin Dingel Signed-off-by: Greg Kroah-Hartman --- include/linux/serial_8250.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include') diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h index 18e21427bce4..5a655ba8d273 100644 --- a/include/linux/serial_8250.h +++ b/include/linux/serial_8250.h @@ -134,6 +134,10 @@ struct uart_8250_port { void (*dl_write)(struct uart_8250_port *, int); struct uart_8250_em485 *em485; + + /* Serial port overrun backoff */ + struct delayed_work overrun_backoff; + u32 overrun_backoff_time_ms; }; static inline struct uart_8250_port *up_to_u8250p(struct uart_port *up) -- cgit v1.2.3 From ac8b6f148fc97e9e10b48bd337ef571b1d1136aa Mon Sep 17 00:00:00 2001 From: Amanoel Dawod Date: Wed, 5 Dec 2018 18:56:37 -0500 Subject: Fonts: New Terminus large console font This patch adds an option to compile-in a high resolution and large Terminus (ter16x32) bitmap console font for use with HiDPI and Retina screens. The font was convereted from standard Terminus ter-i32b.psf (size 16x32) with the help of psftools and minor hand editing deleting useless characters. This patch is non-intrusive, no options are enabled by default so most users won't notice a thing. I am placing my changes under the GPL 2.0 just as source Terminus font. Signed-off-by: Amanoel Dawod Signed-off-by: Greg Kroah-Hartman --- include/linux/font.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/font.h b/include/linux/font.h index d6821769dd1e..51b91c8b69d5 100644 --- a/include/linux/font.h +++ b/include/linux/font.h @@ -32,6 +32,7 @@ struct font_desc { #define ACORN8x8_IDX 8 #define MINI4x6_IDX 9 #define FONT6x10_IDX 10 +#define TER16x32_IDX 11 extern const struct font_desc font_vga_8x8, font_vga_8x16, @@ -43,7 +44,8 @@ extern const struct font_desc font_vga_8x8, font_sun_12x22, font_acorn_8x8, font_mini_4x6, - font_6x10; + font_6x10, + font_ter_16x32; /* Find a font with a specific name */ -- cgit v1.2.3