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path: root/drivers/tty/serial/kgdboc.c
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2023-01-16tty: serial: kgdboc: fix mutex locking order for configure_kgdboc()John Ogness1-15/+5
Several mutexes are taken while setting up console serial ports. In particular, the tty_port->mutex and @console_mutex are taken: serial_pnp_probe serial8250_register_8250_port uart_add_one_port (locks tty_port->mutex) uart_configure_port register_console (locks @console_mutex) In order to synchronize kgdb's tty_find_polling_driver() with register_console(), commit 6193bc90849a ("tty: serial: kgdboc: synchronize tty_find_polling_driver() and register_console()") takes the @console_mutex. However, this leads to the following call chain (with locking): platform_probe kgdboc_probe configure_kgdboc (locks @console_mutex) tty_find_polling_driver uart_poll_init (locks tty_port->mutex) uart_set_options This is clearly deadlock potential due to the reverse lock ordering. Since uart_set_options() requires holding @console_mutex in order to serialize early initialization of the serial-console lock, take the @console_mutex in uart_poll_init() instead of configure_kgdboc(). Since configure_kgdboc() was using @console_mutex for safe traversal of the console list, change it to use the SRCU iterator instead. Add comments to uart_set_options() kerneldoc mentioning that it requires holding @console_mutex (aka the console_list_lock). Fixes: 6193bc90849a ("tty: serial: kgdboc: synchronize tty_find_polling_driver() and register_console()") Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Reviewed-by: Petr Mladek <pmladek@suse.com> [pmladek@suse.com: Export console_srcu_read_lock_is_held() to fix build kgdboc as a module.] Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20230112161213.1434854-1-john.ogness@linutronix.de
2022-12-02tty: serial: kgdboc: use console_list_lock to trap exitJohn Ogness1-3/+3
kgdboc_earlycon_init() uses the console_lock to ensure that no consoles are unregistered until the kgdboc_earlycon is setup. The console_list_lock should be used instead because list synchronization responsibility will be removed from the console_lock in a later change. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20221116162152.193147-39-john.ogness@linutronix.de
2022-12-02tty: serial: kgdboc: synchronize tty_find_polling_driver() and ↵John Ogness1-4/+12
register_console() Calling tty_find_polling_driver() can lead to uart_set_options() being called (via the poll_init() callback of tty_operations) to configure the uart. But uart_set_options() can also be called by register_console() (via the setup() callback of console). Take the console_list_lock to synchronize against register_console() and also use it for console list traversal. This also ensures the console list cannot change until the polling console has been chosen. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20221116162152.193147-38-john.ogness@linutronix.de
2022-12-02tty: serial: kgdboc: use console_list_lock for list traversalJohn Ogness1-0/+12
configure_kgdboc() uses the console_lock for console list iteration. Use the console_list_lock instead because list synchronization responsibility will be removed from the console_lock in a later change. The SRCU iterator could have been used here, but a later change will relocate the locking of the console_list_lock to also provide synchronization against register_console(). Note, the console_lock is still needed to serialize the device() callback with other console operations. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20221116162152.193147-37-john.ogness@linutronix.de
2022-12-02tty: serial: kgdboc: use srcu console list iteratorJohn Ogness1-2/+8
Use srcu console list iteration for safe console list traversal. Note that this is a preparatory change for when console_lock no longer provides synchronization for the console list. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20221116162152.193147-36-john.ogness@linutronix.de
2022-12-02tty: serial: kgdboc: document console_lock usageJohn Ogness1-0/+8
kgdboc_earlycon_init() uses the console_lock to ensure that no consoles are unregistered until the kgdboc_earlycon is setup. This is necessary because the trapping of the exit() callback assumes that the exit() callback is not called before the trap is setup. Explicitly document this non-typical console_lock usage. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20221116162152.193147-9-john.ogness@linutronix.de
2022-12-02serial: kgdboc: Lock console list in probe functionThomas Gleixner1-0/+2
Unprotected list walks are not necessarily safe. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20221116162152.193147-2-john.ogness@linutronix.de
2022-06-27serial: kgdboc: Fix typo in commentXiang wangx1-1/+1
Delete the redundant word 'the'. Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com> Link: https://lore.kernel.org/r/20220620104653.5451-1-wangxiang@cdjrlc.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-18kgdboc: fix return value of __setup handlerRandy Dunlap1-3/+3
__setup() handlers should return 1 to obsolete_checksetup() in init/main.c to indicate that the boot option has been handled. A return of 0 causes the boot option/value to be listed as an Unknown kernel parameter and added to init's (limited) environment strings. So return 1 from kgdboc_option_setup(). Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc7 kgdboc=kbd kgdbts=", will be passed to user space. Run /sbin/init as init process with arguments: /sbin/init with environment: HOME=/ TERM=linux BOOT_IMAGE=/boot/bzImage-517rc7 kgdboc=kbd kgdbts= Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Fixes: 1bd54d851f50 ("kgdboc: Passing ekgdboc to command line causes panic") Fixes: f2d937f3bf00 ("consoles: polling support, kgdboc") Cc: He Zhe <zhe.he@windriver.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: kgdb-bugreport@lists.sourceforge.net Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Douglas Anderson <dianders@chromium.org> Cc: linux-serial@vger.kernel.org Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/r/20220309033018.17936-1-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-20Merge 5.8-rc6 into tty-nextGreg Kroah-Hartman1-16/+16
We need the serial/tty fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-27serial: kgdboc: Fix bad line wrapping in commentDouglas Anderson1-1/+2
In commit a4912303ac6f ("serial: kgdboc: Allow earlycon initialization to be deferred") it looks like Daniel really took Linus's new suggestion about not needing to wrap at 80 columns to heart and he jammed two full lines of comments into one line. Either that or he just somehow accidentally deleted a carriage return when doing final edits on the patch. In either case let's make it look prettier. Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200602124044.1.Iee31247bc080d42a02e167454b1225a1b4283705@changeid Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-26kdb: Switch to use safer dbg_io_ops over console APIsSumit Garg1-16/+16
In kgdb context, calling console handlers aren't safe due to locks used in those handlers which could in turn lead to a deadlock. Although, using oops_in_progress increases the chance to bypass locks in most console handlers but it might not be sufficient enough in case a console uses more locks (VT/TTY is good example). Currently when a driver provides both polling I/O and a console then kdb will output using the console. We can increase robustness by using the currently active polling I/O driver (which should be lockless) instead of the corresponding console. For several common cases (e.g. an embedded system with a single serial port that is used both for console output and debugger I/O) this will result in no console handler being used. In order to achieve this we need to reverse the order of preference to use dbg_io_ops (uses polling I/O mode) over console APIs. So we just store "struct console" that represents debugger I/O in dbg_io_ops and while emitting kdb messages, skip console that matches dbg_io_ops console in order to avoid duplicate messages. After this change, "is_console" param becomes redundant and hence removed. Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Link: https://lore.kernel.org/r/1591264879-25920-5-git-send-email-sumit.garg@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-06-02serial: kgdboc: Allow earlycon initialization to be deferredDaniel Thompson1-1/+38
Currently there is no guarantee that an earlycon will be initialized before kgdboc tries to adopt it. Almost the opposite: on systems with ACPI then if earlycon has no arguments then it is guaranteed that earlycon will not be initialized. This patch mitigates the problem by giving kgdboc_earlycon a second chance during console_init(). This isn't quite as good as stopping during early parameter parsing but it is still early in the kernel boot. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20200430161741.1832050-1-daniel.thompson@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org>
2020-06-02kgdboc: Disable all the early code when kgdboc is a moduleDouglas Anderson1-1/+14
When kgdboc is compiled as a module all of the "ekgdboc" and "kgdb_earlycon" code isn't useful and, in fact, breaks compilation. This is because early_param() isn't defined for modules and that's how this code gets configured. It turns out that this was broken by commit eae3e19ca930 ("kgdboc: Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdboc") and then made worse by commit 220995622da5 ("kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles"). I guess the #ifdef wasn't so useless, even if it wasn't obvious why it was useful. When kgdboc was compiled as a module only "CONFIG_KGDB_SERIAL_CONSOLE_MODULE" was defined, not "CONFIG_KGDB_SERIAL_CONSOLE". That meant that the old module. Let's basically do the same thing that the old code (pre-removal of the #ifdef) did but use "IS_BUILTIN(CONFIG_KGDB_SERIAL_CONSOLE)" to make it more obvious what the point of the check is. We'll fix kgdboc_earlycon in a similar way. Fixes: 220995622da5 ("kgdboc: Add kgdboc_earlycon to support early kgdb using boot consoles") Fixes: eae3e19ca930 ("kgdboc: Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdboc") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200519084345.1.I91670accc8a5ddabab227eb63bb4ad3e2e9d2b58@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-05-18kgdboc: Add kgdboc_earlycon to support early kgdb using boot consolesDouglas Anderson1-0/+136
We want to enable kgdb to debug the early parts of the kernel. Unfortunately kgdb normally is a client of the tty API in the kernel and serial drivers don't register to the tty layer until fairly late in the boot process. Serial drivers do, however, commonly register a boot console. Let's enable the kgdboc driver to work with boot consoles to provide early debugging. This change co-opts the existing read() function pointer that's part of "struct console". It's assumed that if a boot console (with the flag CON_BOOT) has implemented read() that both the read() and write() function are polling functions. That means they work without interrupts and read() will return immediately (with 0 bytes read) if there's nothing to read. This should be a safe assumption since it appears that no current boot consoles implement read() right now and there seems no reason to do so unless they wanted to support "kgdboc_earlycon". The normal/expected way to make all this work is to use "kgdboc_earlycon" and "kgdboc" together. You should point them both to the same physical serial connection. At boot time, as the system transitions from the boot console to the normal console (and registers a tty), kgdb will switch over. One awkward part of all this, though, is that there can be a window where the boot console goes away and we can't quite transtion over to the main kgdboc that uses the tty layer. There are two main problems: 1. The act of registering the tty doesn't cause any call into kgdboc so there is a window of time when the tty is there but kgdboc's init code hasn't been called so we can't transition to it. 2. On some serial drivers the normal console inits (and replaces the boot console) quite early in the system. Presumably these drivers were coded up before earlycon worked as well as it does today and probably they don't need to do this anymore, but it causes us problems nontheless. Problem #1 is not too big of a deal somewhat due to the luck of probe ordering. kgdboc is last in the tty/serial/Makefile so its probe gets right after all other tty devices. It's not fun to rely on this, but it does work for the most part. Problem #2 is a big deal, but only for some serial drivers. Other serial drivers end up registering the console (which gets rid of the boot console) and tty at nearly the same time. The way we'll deal with the window when the system has stopped using the boot console and the time when we're setup using the tty is to keep using the boot console. This may sound surprising, but it has been found to work well in practice. If it doesn't work, it shouldn't be too hard for a given serial driver to make it keep working. Specifically, it's expected that the read()/write() function provided in the boot console should be the same (or nearly the same) as the normal kgdb polling functions. That means continuing to use them should work just fine. To make things even more likely to work work we'll also trap the recently added exit() function in the boot console we're using and delay any calls to it until we're all done with the boot console. NOTE: there could be ways to use all this in weird / unexpected ways. If you do something like this, it's a bit of a buyer beware situation. Specifically: - If you specify only "kgdboc_earlycon" but not "kgdboc" then (depending on your serial driver) things will probably work OK, but you'll get a warning printed the first time you use kgdb after the boot console is gone. You'd only be able to do this, of course, if the serial driver you're running atop provided an early boot console. - If your "kgdboc_earlycon" and "kgdboc" devices are not the same device things should work OK, but it'll be your job to switch over which device you're monitoring (including figuring out how to switch over gdb in-flight if you're using it). When trying to enable "kgdboc_earlycon" it should be noted that the names that are registered through the boot console layer and the tty layer are not the same for the same port. For example when debugging on one board I'd need to pass "kgdboc_earlycon=qcom_geni kgdboc=ttyMSM0" to enable things properly. Since digging up the boot console name is a pain and there will rarely be more than one boot console enabled, you can provide the "kgdboc_earlycon" parameter without specifying the name of the boot console. In this case we'll just pick the first boot that implements read() that we find. This new "kgdboc_earlycon" parameter should be contrasted to the existing "ekgdboc" parameter. While both provide a way to debug very early, the usage and mechanisms are quite different. Specifically "kgdboc_earlycon" is meant to be used in tandem with "kgdboc" and there is a transition from one to the other. The "ekgdboc" parameter, on the other hand, replaces the "kgdboc" parameter. It runs the same logic as the "kgdboc" parameter but just relies on your TTY driver being present super early. The only known usage of the old "ekgdboc" parameter is documented as "ekgdboc=kbd earlyprintk=vga". It should be noted that "kbd" has special treatment allowing it to init early as a tty device. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Tested-by: Sumit Garg <sumit.garg@linaro.org> Link: https://lore.kernel.org/r/20200507130644.v4.8.I8fba5961bf452ab92350654aa61957f23ecf0100@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-05-18kgdboc: Remove useless #ifdef CONFIG_KGDB_SERIAL_CONSOLE in kgdbocDouglas Anderson1-2/+0
This file is only ever compiled if that config is on since the Makefile says: obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o Let's get rid of the useless #ifdef. Reported-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200507130644.v4.7.Icb528f03d0026d957e60f537aa711ada6fd219dc@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-05-18kgdboc: Use a platform device to handle tty drivers showing up lateDouglas Anderson1-25/+101
If you build CONFIG_KGDB_SERIAL_CONSOLE into the kernel then you should be able to have KGDB init itself at bootup by specifying the "kgdboc=..." kernel command line parameter. This has worked OK for me for many years, but on a new device I switched to it stopped working. The problem is that on this new device the serial driver gets its probe deferred. Now when kgdb initializes it can't find the tty driver and when it gives up it never tries again. We could try to find ways to move up the initialization of the serial driver and such a thing might be worthwhile, but it's nice to be robust against serial drivers that load late. We could move kgdb to init itself later but that penalizes our ability to debug early boot code on systems where the driver inits early. We could roll our own system of detecting when new tty drivers get loaded and then use that to figure out when kgdb can init, but that's ugly. Instead, let's jump on the -EPROBE_DEFER bandwagon. We'll create a singleton instance of a "kgdboc" platform device. If we can't find our tty device when the singleton "kgdboc" probes we'll return -EPROBE_DEFER which means that the system will call us back later to try again when the tty device might be there. We won't fully transition all of the kgdboc to a platform device because early kgdb initialization (via the "ekgdboc" kernel command line parameter) still runs before the platform device has been created. The kgdb platform device is merely used as a convenient way to hook into the system's normal probe deferral mechanisms. As part of this, we'll ever-so-slightly change how the "kgdboc=..." kernel command line parameter works. Previously if you booted up and kgdb couldn't find the tty driver then later reading '/sys/module/kgdboc/parameters/kgdboc' would return a blank string. Now kgdb will keep track of the string that came as part of the command line and give it back to you. It's expected that this should be an OK change. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20200507130644.v4.3.I4a493cfb0f9f740ce8fd2ab58e62dc92d18fed30@changeid [daniel.thompson@linaro.org: Make config_mutex static] Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-05-18Revert "kgdboc: disable the console lock when in kgdb"Douglas Anderson1-4/+0
This reverts commit 81eaadcae81b4c1bf01649a3053d1f54e2d81cf1. Commit 81eaadcae81b ("kgdboc: disable the console lock when in kgdb") is no longer needed now that we have the patch ("kgdb: Disable WARN_CONSOLE_UNLOCKED for all kgdb"). Revert it. Signed-off-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20200507130644.v4.2.I02258eee1497e55bcbe8dc477de90369c7c7c2c5@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-02-10kgdboc: Use for_each_console() helperAndy Shevchenko1-3/+1
Replace open coded single-linked list iteration loop with for_each_console() helper in use. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20200124161132.65519-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-30kgdboc: disable the console lock when in kgdbDouglas Anderson1-0/+4
After commit ddde3c18b700 ("vt: More locking checks") kdb / kgdb has become useless because my console is filled with spews of: WARNING: CPU: 0 PID: 0 at .../drivers/tty/vt/vt.c:3846 con_is_visible+0x50/0x74 CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-rc1+ #48 Hardware name: Rockchip (Device Tree) Backtrace: [<c020ce9c>] (dump_backtrace) from [<c020d188>] (show_stack+0x20/0x24) [<c020d168>] (show_stack) from [<c0a8fc14>] (dump_stack+0xb0/0xd0) [<c0a8fb64>] (dump_stack) from [<c0232c58>] (__warn+0xec/0x11c) [<c0232b6c>] (__warn) from [<c0232dc4>] (warn_slowpath_null+0x4c/0x58) [<c0232d78>] (warn_slowpath_null) from [<c06338a0>] (con_is_visible+0x50/0x74) [<c0633850>] (con_is_visible) from [<c0634078>] (con_scroll+0x108/0x1ac) [<c0633f70>] (con_scroll) from [<c0634160>] (lf+0x44/0x88) [<c063411c>] (lf) from [<c06363ec>] (vt_console_print+0x1a4/0x2bc) [<c0636248>] (vt_console_print) from [<c02f628c>] (vkdb_printf+0x420/0x8a4) [<c02f5e6c>] (vkdb_printf) from [<c02f6754>] (kdb_printf+0x44/0x60) [<c02f6714>] (kdb_printf) from [<c02fa6f4>] (kdb_main_loop+0xf4/0x6e0) [<c02fa600>] (kdb_main_loop) from [<c02fd5f0>] (kdb_stub+0x268/0x398) [<c02fd388>] (kdb_stub) from [<c02f3ba0>] (kgdb_cpu_enter+0x1f8/0x674) [<c02f39a8>] (kgdb_cpu_enter) from [<c02f4330>] (kgdb_handle_exception+0x1c4/0x1fc) [<c02f416c>] (kgdb_handle_exception) from [<c0210fe0>] (kgdb_compiled_brk_fn+0x30/0x3c) [<c0210fb0>] (kgdb_compiled_brk_fn) from [<c020d7ac>] (do_undefinstr+0x180/0x1a0) [<c020d62c>] (do_undefinstr) from [<c0201b44>] (__und_svc_finish+0x0/0x3c) ... [<c02f3224>] (kgdb_breakpoint) from [<c02f3310>] (sysrq_handle_dbg+0x58/0x6c) [<c02f32b8>] (sysrq_handle_dbg) from [<c062abf0>] (__handle_sysrq+0xac/0x154) Let's disable this warning when we're in kgdb to avoid the spew. The whole system is stopped when we're in kgdb so we can't exactly wait for someone else to drop the lock. Presumably the best we can do is to disable the warning and hope for the best. Fixes: ddde3c18b700 ("vt: More locking checks") Cc: Daniel Vetter <daniel.vetter@intel.com> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20190725183551.169208-1-dianders@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-28Disable kgdboc failed by echo space to /sys/module/kgdboc/parameters/kgdbocWentao Wang1-1/+3
Echo "" to /sys/module/kgdboc/parameters/kgdboc will fail with "No such device” error. This is caused by function "configure_kgdboc" who init err to ENODEV when the config is empty (legal input) the code go out with ENODEV returned. Fixes: 2dd453168643 ("kgdboc: Fix restrict error") Signed-off-by: Wentao Wang <witallwang@gmail.com> Cc: stable <stable@vger.kernel.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-06kgdboc: fix KASAN global-out-of-bounds bug in param_set_kgdboc_var()Macpaul Lin1-2/+2
This patch is trying to fix KE issue due to "BUG: KASAN: global-out-of-bounds in param_set_kgdboc_var+0x194/0x198" reported by Syzkaller scan." [26364:syz-executor0][name:report8t]BUG: KASAN: global-out-of-bounds in param_set_kgdboc_var+0x194/0x198 [26364:syz-executor0][name:report&]Read of size 1 at addr ffffff900e44f95f by task syz-executor0/26364 [26364:syz-executor0][name:report&] [26364:syz-executor0]CPU: 7 PID: 26364 Comm: syz-executor0 Tainted: G W 0 [26364:syz-executor0]Call trace: [26364:syz-executor0][<ffffff9008095cf8>] dump_bacIctrace+Ox0/0x470 [26364:syz-executor0][<ffffff9008096de0>] show_stack+0x20/0x30 [26364:syz-executor0][<ffffff90089cc9c8>] dump_stack+Oxd8/0x128 [26364:syz-executor0][<ffffff90084edb38>] print_address_description +0x80/0x4a8 [26364:syz-executor0][<ffffff90084ee270>] kasan_report+Ox178/0x390 [26364:syz-executor0][<ffffff90084ee4a0>] _asan_report_loadi_noabort+Ox18/0x20 [26364:syz-executor0][<ffffff9008b092ac>] param_set_kgdboc_var+Ox194/0x198 [26364:syz-executor0][<ffffff900813af64>] param_attr_store+Ox14c/0x270 [26364:syz-executor0][<ffffff90081394c8>] module_attr_store+0x60/0x90 [26364:syz-executor0][<ffffff90086690c0>] sysfs_kl_write+Ox100/0x158 [26364:syz-executor0][<ffffff9008666d84>] kernfs_fop_write+0x27c/0x3a8 [26364:syz-executor0][<ffffff9008508264>] do_loop_readv_writev+0x114/0x1b0 [26364:syz-executor0][<ffffff9008509ac8>] do_readv_writev+0x4f8/0x5e0 [26364:syz-executor0][<ffffff9008509ce4>] vfs_writev+0x7c/Oxb8 [26364:syz-executor0][<ffffff900850ba64>] SyS_writev+Oxcc/0x208 [26364:syz-executor0][<ffffff90080883f0>] elO_svc_naked +0x24/0x28 [26364:syz-executor0][name:report&] [26364:syz-executor0][name:report&]The buggy address belongs to the variable: [26364:syz-executor0][name:report&] kgdb_tty_line+Ox3f/0x40 [26364:syz-executor0][name:report&] [26364:syz-executor0][name:report&]Memory state around the buggy address: [26364:syz-executor0] ffffff900e44f800: 00 00 00 00 00 04 fa fa fa fa fa fa 00 fa fa fa [26364:syz-executor0] ffffff900e44f880: fa fa fa fa 00 fa fa fa fa fa fa fa 00 fa fa fa [26364:syz-executor0]> ffffff900e44f900: fa fa fa fa 04 fa fa fa fa fa fa fa 00 00 00 00 [26364:syz-executor0][name:report&] ^ [26364:syz-executor0] ffffff900e44f980: 00 fa fa fa fa fa fa fa 04 fa fa fa fa fa fa fa [26364:syz-executor0] ffffff900e44fa00: 04 fa fa fa fa fa fa fa 00 fa fa fa fa fa fa fa [26364:syz-executor0][name:report&] [26364:syz-executor0][name:panic&]Disabling lock debugging due to kernel taint [26364:syz-executor0]------------[cut here]------------ After checking the source code, we've found there might be an out-of-bounds access to "config[len - 1]" array when the variable "len" is zero. Signed-off-by: Macpaul Lin <macpaul@gmail.com> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-20kgdboc: Fix warning with module buildLaura Abbott1-18/+19
After 2dd453168643 ("kgdboc: Fix restrict error"), kgdboc_option_setup is now only used when built in, resulting in a warning when compiled as a module: drivers/tty/serial/kgdboc.c:134:12: warning: 'kgdboc_option_setup' defined but not used [-Wunused-function] static int kgdboc_option_setup(char *opt) ^~~~~~~~~~~~~~~~~~~ Move the function under the appropriate ifdef for builtin only. Fixes: 2dd453168643 ("kgdboc: Fix restrict error") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-18kgdboc: Fix restrict errorLaura Abbott1-4/+2
There's an error when compiled with restrict: drivers/tty/serial/kgdboc.c: In function ‘configure_kgdboc’: drivers/tty/serial/kgdboc.c:137:2: error: ‘strcpy’ source argument is the same as destination [-Werror=restrict] strcpy(config, opt); ^~~~~~~~~~~~~~~~~~~ As the error implies, this is from trying to use config as both source and destination. Drop the call to the function where config is the argument since nothing else happens in the function. Signed-off-by: Laura Abbott <labbott@redhat.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-18kgdboc: Change printk to the right fashionHe Zhe1-5/+7
pr_* is preferred according to scripts/checkpatch.pl. Cc: jason.wessel@windriver.com Cc: gregkh@linuxfoundation.org Cc: jslaby@suse.com Signed-off-by: He Zhe <zhe.he@windriver.com> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-18kgdboc: Passing ekgdboc to command line causes panicHe Zhe1-0/+5
kgdboc_option_setup does not check input argument before passing it to strlen. The argument would be a NULL pointer if "ekgdboc", without its value, is set in command line and thus cause the following panic. PANIC: early exception 0xe3 IP 10:ffffffff8fbbb620 error 0 cr2 0x0 [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.18-rc8+ #1 [ 0.000000] RIP: 0010:strlen+0x0/0x20 ... [ 0.000000] Call Trace [ 0.000000] ? kgdboc_option_setup+0x9/0xa0 [ 0.000000] ? kgdboc_early_init+0x6/0x1b [ 0.000000] ? do_early_param+0x4d/0x82 [ 0.000000] ? parse_args+0x212/0x330 [ 0.000000] ? rdinit_setup+0x26/0x26 [ 0.000000] ? parse_early_options+0x20/0x23 [ 0.000000] ? rdinit_setup+0x26/0x26 [ 0.000000] ? parse_early_param+0x2d/0x39 [ 0.000000] ? setup_arch+0x2f7/0xbf4 [ 0.000000] ? start_kernel+0x5e/0x4c2 [ 0.000000] ? load_ucode_bsp+0x113/0x12f [ 0.000000] ? secondary_startup_64+0xa5/0xb0 This patch adds a check to prevent the panic. Cc: stable@vger.kernel.org Cc: jason.wessel@windriver.com Cc: gregkh@linuxfoundation.org Cc: jslaby@suse.com Signed-off-by: He Zhe <zhe.he@windriver.com> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-15Merge tag 'modules-for-v4.15' of ↵Linus Torvalds1-1/+2
git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux Pull module updates from Jessica Yu: "Summary of modules changes for the 4.15 merge window: - treewide module_param_call() cleanup, fix up set/get function prototype mismatches, from Kees Cook - minor code cleanups" * tag 'modules-for-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux: module: Do not paper over type mismatches in module_param_call() treewide: Fix function prototypes for module_param_call() module: Prepare to convert all module_param_call() prototypes kernel/module: Delete an error message for a failed memory allocation in add_module_usage()
2017-11-08tty: serial: Remove redundant license textGreg Kroah-Hartman1-4/+0
Now that the SPDX tag is in all tty files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Jiri Slaby <jslaby@suse.com> Cc: Eric Anholt <eric@anholt.net> Cc: Stefan Wahren <stefan.wahren@i2se.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Ray Jui <rjui@broadcom.com> Cc: Scott Branden <sbranden@broadcom.com> Cc: bcm-kernel-feedback-list@broadcom.com Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Joachim Eastwood <manabian@gmail.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Tobias Klauser <tklauser@distanz.ch> Cc: Russell King <linux@armlinux.org.uk> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Richard Genoud <richard.genoud@gmail.com> Cc: Alexander Shiyan <shc_work@mail.ru> Cc: Baruch Siach <baruch@tkos.co.il> Cc: Pat Gefre <pfg@sgi.com> Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Vladimir Zapolskiy <vz@mleia.com> Cc: Sylvain Lemieux <slemieux.tyco@gmail.com> Cc: Carlo Caione <carlo@caione.org> Cc: Kevin Hilman <khilman@baylibre.com> Cc: Liviu Dudau <liviu.dudau@arm.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Andy Gross <andy.gross@linaro.org> Cc: David Brown <david.brown@linaro.org> Cc: "Andreas Färber" <afaerber@suse.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Laxman Dewangan <ldewangan@nvidia.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Jonathan Hunter <jonathanh@nvidia.com> Cc: Barry Song <baohua@kernel.org> Cc: Patrice Chotard <patrice.chotard@st.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@st.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Peter Korsgaard <jacmet@sunsite.dk> Cc: Timur Tabi <timur@tabi.org> Cc: Tony Prisk <linux@prisktech.co.nz> Cc: Michal Simek <michal.simek@xilinx.com> Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-08tty: add SPDX identifiers to all remaining files in drivers/tty/Greg Kroah-Hartman1-0/+1
It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the drivers/tty files files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Jiri Slaby <jslaby@suse.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: James Hogan <jhogan@kernel.org> Cc: Rob Herring <robh@kernel.org> Cc: Eric Anholt <eric@anholt.net> Cc: Stefan Wahren <stefan.wahren@i2se.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Ray Jui <rjui@broadcom.com> Cc: Scott Branden <sbranden@broadcom.com> Cc: bcm-kernel-feedback-list@broadcom.com Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Joachim Eastwood <manabian@gmail.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Tobias Klauser <tklauser@distanz.ch> Cc: Russell King <linux@armlinux.org.uk> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Richard Genoud <richard.genoud@gmail.com> Cc: Alexander Shiyan <shc_work@mail.ru> Cc: Baruch Siach <baruch@tkos.co.il> Cc: "Maciej W. Rozycki" <macro@linux-mips.org> Cc: "Uwe Kleine-König" <kernel@pengutronix.de> Cc: Pat Gefre <pfg@sgi.com> Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Vladimir Zapolskiy <vz@mleia.com> Cc: Sylvain Lemieux <slemieux.tyco@gmail.com> Cc: Carlo Caione <carlo@caione.org> Cc: Kevin Hilman <khilman@baylibre.com> Cc: Liviu Dudau <liviu.dudau@arm.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Andy Gross <andy.gross@linaro.org> Cc: David Brown <david.brown@linaro.org> Cc: "Andreas Färber" <afaerber@suse.de> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Laxman Dewangan <ldewangan@nvidia.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Jonathan Hunter <jonathanh@nvidia.com> Cc: Barry Song <baohua@kernel.org> Cc: Patrice Chotard <patrice.chotard@st.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@st.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Peter Korsgaard <jacmet@sunsite.dk> Cc: Timur Tabi <timur@tabi.org> Cc: Tony Prisk <linux@prisktech.co.nz> Cc: Michal Simek <michal.simek@xilinx.com> Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Jiri Slaby <jslaby@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-10-31treewide: Fix function prototypes for module_param_call()Kees Cook1-1/+2
Several function prototypes for the set/get functions defined by module_param_call() have a slightly wrong argument types. This fixes those in an effort to clean up the calls when running under type-enforced compiler instrumentation for CFI. This is the result of running the following semantic patch: @match_module_param_call_function@ declarer name module_param_call; identifier _name, _set_func, _get_func; expression _arg, _mode; @@ module_param_call(_name, _set_func, _get_func, _arg, _mode); @fix_set_prototype depends on match_module_param_call_function@ identifier match_module_param_call_function._set_func; identifier _val, _param; type _val_type, _param_type; @@ int _set_func( -_val_type _val +const char * _val , -_param_type _param +const struct kernel_param * _param ) { ... } @fix_get_prototype depends on match_module_param_call_function@ identifier match_module_param_call_function._get_func; identifier _val, _param; type _val_type, _param_type; @@ int _get_func( -_val_type _val +char * _val , -_param_type _param +const struct kernel_param * _param ) { ... } Two additional by-hand changes are included for places where the above Coccinelle script didn't notice them: drivers/platform/x86/thinkpad_acpi.c fs/lockd/svc.c Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jessica Yu <jeyu@kernel.org>
2013-09-04treewide: Convert retrun typos to returnJoe Perches1-1/+1
Tyops should be fixed. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-10-13Merge tag 'for_linus-3.7' of ↵Linus Torvalds1-1/+2
git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb Pull KGDB/KDB fixes and cleanups from Jason Wessel: "Cleanups - Clean up compile warnings in kgdboc.c and x86/kernel/kgdb.c - Add module event hooks for simplified debugging with gdb Fixes - Fix kdb to stop paging with 'q' on bta and dmesg - Fix for data that scrolls off the vga console due to line wrapping when using the kdb pager New - The debug core registers for kernel module events which allows a kernel aware gdb to automatically load symbols and break on entry to a kernel module - Allow kgdboc=kdb to setup kdb on the vga console" * tag 'for_linus-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb: tty/console: fix warnings in drivers/tty/serial/kgdboc.c kdb,vt_console: Fix missed data due to pager overruns kdb: Fix dmesg/bta scroll to quit with 'q' kgdboc: Accept either kbd or kdb to activate the vga + keyboard kdb shell kgdb,x86: fix warning about unused variable mips,kgdb: fix recursive page fault with CONFIG_KPROBES kgdb: Add module event hooks
2012-10-12kgdboc: Accept either kbd or kdb to activate the vga + keyboard kdb shellJason Wessel1-1/+2
It is a common enough mistake for people to specify "kdb" when they meant to type "kbd" that the kgdboc can just accept both since they both mean the same thing anyway. Specifically it is for the case where you want kdb to be active on your graphics console + keyboard (where kbd was the original abbreviation for keyboard). With this change kgdboc will now accept either to mean the same thing: kgdboc=kbd kgdboc=kdb Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-10-02Merge branch 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wqLinus Torvalds1-1/+1
Pull workqueue changes from Tejun Heo: "This is workqueue updates for v3.7-rc1. A lot of activities this round including considerable API and behavior cleanups. * delayed_work combines a timer and a work item. The handling of the timer part has always been a bit clunky leading to confusing cancelation API with weird corner-case behaviors. delayed_work is updated to use new IRQ safe timer and cancelation now works as expected. * Another deficiency of delayed_work was lack of the counterpart of mod_timer() which led to cancel+queue combinations or open-coded timer+work usages. mod_delayed_work[_on]() are added. These two delayed_work changes make delayed_work provide interface and behave like timer which is executed with process context. * A work item could be executed concurrently on multiple CPUs, which is rather unintuitive and made flush_work() behavior confusing and half-broken under certain circumstances. This problem doesn't exist for non-reentrant workqueues. While non-reentrancy check isn't free, the overhead is incurred only when a work item bounces across different CPUs and even in simulated pathological scenario the overhead isn't too high. All workqueues are made non-reentrant. This removes the distinction between flush_[delayed_]work() and flush_[delayed_]_work_sync(). The former is now as strong as the latter and the specified work item is guaranteed to have finished execution of any previous queueing on return. * In addition to the various bug fixes, Lai redid and simplified CPU hotplug handling significantly. * Joonsoo introduced system_highpri_wq and used it during CPU hotplug. There are two merge commits - one to pull in IRQ safe timer from tip/timers/core and the other to pull in CPU hotplug fixes from wq/for-3.6-fixes as Lai's hotplug restructuring depended on them." Fixed a number of trivial conflicts, but the more interesting conflicts were silent ones where the deprecated interfaces had been used by new code in the merge window, and thus didn't cause any real data conflicts. Tejun pointed out a few of them, I fixed a couple more. * 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (46 commits) workqueue: remove spurious WARN_ON_ONCE(in_irq()) from try_to_grab_pending() workqueue: use cwq_set_max_active() helper for workqueue_set_max_active() workqueue: introduce cwq_set_max_active() helper for thaw_workqueues() workqueue: remove @delayed from cwq_dec_nr_in_flight() workqueue: fix possible stall on try_to_grab_pending() of a delayed work item workqueue: use hotcpu_notifier() for workqueue_cpu_down_callback() workqueue: use __cpuinit instead of __devinit for cpu callbacks workqueue: rename manager_mutex to assoc_mutex workqueue: WORKER_REBIND is no longer necessary for idle rebinding workqueue: WORKER_REBIND is no longer necessary for busy rebinding workqueue: reimplement idle worker rebinding workqueue: deprecate __cancel_delayed_work() workqueue: reimplement cancel_delayed_work() using try_to_grab_pending() workqueue: use mod_delayed_work() instead of __cancel + queue workqueue: use irqsafe timer for delayed_work workqueue: clean up delayed_work initializers and add missing one workqueue: make deferrable delayed_work initializer names consistent workqueue: cosmetic whitespace updates for macro definitions workqueue: deprecate system_nrt[_freezable]_wq workqueue: deprecate flush[_delayed]_work_sync() ...
2012-09-26tty/serial: Add kgdb_nmi driverAnton Vorontsov1-0/+9
This special driver makes it possible to temporary use NMI debugger port as a normal console by issuing 'nmi_console' command (assuming that the port is attached to KGDB). Unlike KDB's disable_nmi command, with this driver you are always able to go back to the debugger using KGDB escape sequence ($3#33). This is because this console driver processes the input in NMI context, and thus is able to intercept the magic sequence. Note that since the console interprets input and uses polling communication methods, for things like PPP it is still better to fully detach debugger port from the KGDB NMI (i.e. disable_nmi), and use raw console. Usually, to enter the debugger one have to type the magic sequence, so initially the kernel will print the following prompt on the NMI debugger console: Type $3#33 to enter the debugger> For convenience, there is a kgdb_fiq.knock kernel command line option, when set to 0, this turns the special command to just a return key press, so the kernel will be printing this: Hit <return> to enter the debugger> This is more convenient for long debugging sessions, although it makes nmi_console feature somewhat useless. And for the cases when NMI connected to a dedicated button, the knocking can be disabled altogether by setting kgdb_fiq.knock to -1. Suggested-by: Colin Cross <ccross@android.com> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Acked-by: Alan Cox <alan@linux.intel.com> Acked-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-08-20workqueue: deprecate flush[_delayed]_work_sync()Tejun Heo1-1/+1
flush[_delayed]_work_sync() are now spurious. Mark them deprecated and convert all users to flush[_delayed]_work(). If you're cc'd and wondering what's going on: Now all workqueues are non-reentrant and the regular flushes guarantee that the work item is not pending or running on any CPU on return, so there's no reason to use the sync flushes at all and they're going away. This patch doesn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Mattia Dongili <malattia@linux.it> Cc: Kent Yoder <key@linux.vnet.ibm.com> Cc: David Airlie <airlied@linux.ie> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Karsten Keil <isdn@linux-pingi.de> Cc: Bryan Wu <bryan.wu@canonical.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Alasdair Kergon <agk@redhat.com> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de> Cc: David Woodhouse <dwmw2@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: linux-wireless@vger.kernel.org Cc: Anton Vorontsov <cbou@mail.ru> Cc: Sangbeom Kim <sbkim73@samsung.com> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Eric Van Hensbergen <ericvh@gmail.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Petr Vandrovec <petr@vandrovec.name> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Avi Kivity <avi@redhat.com>
2011-10-31tty: Add module.h to drivers/tty users who just expect it there.Paul Gortmaker1-0/+1
We are cleaning up the issue that means module.h is omnipresent. These tty users are the people who implictly are relying on that. Fix up the real users to call out the include that they really need. In the case of jsm_driver.c file, it had moduleparam.h but that isn't enough and it needs the full module.h Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-03-25kgdboc,kgdbts: strlen() doesn't count the terminatorDan Carpenter1-1/+1
This is an off by one because strlen() doesn't count the null terminator. We strcpy() these strings into an array of size MAX_CONFIG_LEN. Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2011-01-13tty: move drivers/serial/ to drivers/tty/serial/Greg Kroah-Hartman1-0/+328
The serial drivers are really just tty drivers, so move them to drivers/tty/ to make things a bit neater overall. This is part of the tty/serial driver movement proceedure as proposed by Arnd Bergmann and approved by everyone involved a number of months ago. Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Rogier Wolff <R.E.Wolff@bitwizard.nl> Cc: Michael H. Warfield <mhw@wittsend.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>