From 6878e7de6af726de47f9f3bec649c3f49e786586 Mon Sep 17 00:00:00 2001 From: Dmitry Torokhov Date: Wed, 13 Sep 2017 16:29:48 -0700 Subject: driver core: suppress sending MODALIAS in UNBIND uevents The current udev rules cause modules to be loaded on all device events save for "remove". With the introduction of KOBJ_BIND/KOBJ_UNBIND this causes issues, as driver modules that have devices bound to their drivers get immediately reloaded, and it appears to the user that module unloading doe snot work. The standard udev matching rule is foillowing: ENV{MODALIAS}=="?*", RUN{builtin}+="kmod load $env{MODALIAS}" Given that MODALIAS data is not terribly useful for UNBIND event, let's zap it from the generated uevent environment until we get userspace updated with the correct udev rule that only loads modules on "add" event. Reported-by: Jakub Kicinski Tested-by: Jakub Kicinski Fixes: 1455cf8dbfd0 ("driver core: emit uevents when device is bound ...") Signed-off-by: Dmitry Torokhov Signed-off-by: Greg Kroah-Hartman --- lib/kobject_uevent.c | 49 +++++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 41 insertions(+), 8 deletions(-) (limited to 'lib') diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index e590523ea476..f237a09a5862 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -294,6 +294,26 @@ static void cleanup_uevent_env(struct subprocess_info *info) } #endif +static void zap_modalias_env(struct kobj_uevent_env *env) +{ + static const char modalias_prefix[] = "MODALIAS="; + int i; + + for (i = 0; i < env->envp_idx;) { + if (strncmp(env->envp[i], modalias_prefix, + sizeof(modalias_prefix) - 1)) { + i++; + continue; + } + + if (i != env->envp_idx - 1) + memmove(&env->envp[i], &env->envp[i + 1], + sizeof(env->envp[i]) * env->envp_idx - 1); + + env->envp_idx--; + } +} + /** * kobject_uevent_env - send an uevent with environmental data * @@ -409,16 +429,29 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, } } - /* - * Mark "add" and "remove" events in the object to ensure proper - * events to userspace during automatic cleanup. If the object did - * send an "add" event, "remove" will automatically generated by - * the core, if not already done by the caller. - */ - if (action == KOBJ_ADD) + switch (action) { + case KOBJ_ADD: + /* + * Mark "add" event so we can make sure we deliver "remove" + * event to userspace during automatic cleanup. If + * the object did send an "add" event, "remove" will + * automatically generated by the core, if not already done + * by the caller. + */ kobj->state_add_uevent_sent = 1; - else if (action == KOBJ_REMOVE) + break; + + case KOBJ_REMOVE: kobj->state_remove_uevent_sent = 1; + break; + + case KOBJ_UNBIND: + zap_modalias_env(env); + break; + + default: + break; + } mutex_lock(&uevent_sock_mutex); /* we will send an event, so request a new sequence number */ -- cgit v1.2.3 From 8cb5d7482810b7eb1bb05bf4f71bc93ce35e5896 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Tue, 3 Oct 2017 16:16:01 -0700 Subject: lib/lz4: make arrays static const, reduces object code size Don't populate the read-only arrays dec32table and dec64table on the stack, instead make them both static const. Makes the object code smaller by over 10K bytes: Before: text data bss dec hex filename 31500 0 0 31500 7b0c lib/lz4/lz4_decompress.o After: text data bss dec hex filename 20237 176 0 20413 4fbd lib/lz4/lz4_decompress.o (gcc version 7.2.0 x86_64) Link: http://lkml.kernel.org/r/20170921221939.20820-1-colin.king@canonical.com Signed-off-by: Colin Ian King Cc: Christophe JAILLET Cc: Sven Schmidt <4sschmid@informatik.uni-hamburg.de> Cc: Arnd Bergmann Cc: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/lz4/lz4_decompress.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c index bd3574312b82..141734d255e4 100644 --- a/lib/lz4/lz4_decompress.c +++ b/lib/lz4/lz4_decompress.c @@ -85,8 +85,8 @@ static FORCE_INLINE int LZ4_decompress_generic( const BYTE * const lowLimit = lowPrefix - dictSize; const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize; - const unsigned int dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 }; - const int dec64table[] = { 0, 0, 0, -1, 0, 1, 2, 3 }; + static const unsigned int dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 }; + static const int dec64table[] = { 0, 0, 0, -1, 0, 1, 2, 3 }; const int safeDecode = (endOnInput == endOnInputSize); const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB))); -- cgit v1.2.3 From a70e43a59de9316e6fbad3b65557d0a24c099aca Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Tue, 3 Oct 2017 16:16:13 -0700 Subject: lib/idr.c: fix comment for idr_replace() idr_replace() returns the old value on success, not 0. Link: http://lkml.kernel.org/r/20170918162642.37511-1-ebiggers3@gmail.com Signed-off-by: Eric Biggers Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/idr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/lib/idr.c b/lib/idr.c index f9adf4805fd7..edd9b2be1651 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -146,8 +146,8 @@ EXPORT_SYMBOL(idr_get_next_ext); * idr_alloc() and idr_remove() (as long as the ID being removed is not * the one being replaced!). * - * Returns: 0 on success. %-ENOENT indicates that @id was not found. - * %-EINVAL indicates that @id or @ptr were not valid. + * Returns: the old value on success. %-ENOENT indicates that @id was not + * found. %-EINVAL indicates that @id or @ptr were not valid. */ void *idr_replace(struct idr *idr, void *ptr, int id) { -- cgit v1.2.3 From 656d61ce9666209c4c4a13c71902d3ee70d1ff6f Mon Sep 17 00:00:00 2001 From: Sergey Senozhatsky Date: Tue, 3 Oct 2017 16:16:45 -0700 Subject: lib/ratelimit.c: use deferred printk() version printk_ratelimit() invokes ___ratelimit() which may invoke a normal printk() (pr_warn() in this particular case) to warn about suppressed output. Given that printk_ratelimit() may be called from anywhere, that pr_warn() is dangerous - it may end up deadlocking the system. Fix ___ratelimit() by using deferred printk(). Sasha reported the following lockdep error: : Unregister pv shared memory for cpu 8 : select_fallback_rq: 3 callbacks suppressed : process 8583 (trinity-c78) no longer affine to cpu8 : : ====================================================== : WARNING: possible circular locking dependency detected : 4.14.0-rc2-next-20170927+ #252 Not tainted : ------------------------------------------------------ : migration/8/62 is trying to acquire lock: : (&port_lock_key){-.-.}, at: serial8250_console_write() : : but task is already holding lock: : (&rq->lock){-.-.}, at: sched_cpu_dying() : : which lock already depends on the new lock. : : : the existing dependency chain (in reverse order) is: : : -> #3 (&rq->lock){-.-.}: : __lock_acquire() : lock_acquire() : _raw_spin_lock() : task_fork_fair() : sched_fork() : copy_process.part.31() : _do_fork() : kernel_thread() : rest_init() : start_kernel() : x86_64_start_reservations() : x86_64_start_kernel() : verify_cpu() : : -> #2 (&p->pi_lock){-.-.}: : __lock_acquire() : lock_acquire() : _raw_spin_lock_irqsave() : try_to_wake_up() : default_wake_function() : woken_wake_function() : __wake_up_common() : __wake_up_common_lock() : __wake_up() : tty_wakeup() : tty_port_default_wakeup() : tty_port_tty_wakeup() : uart_write_wakeup() : serial8250_tx_chars() : serial8250_handle_irq.part.25() : serial8250_default_handle_irq() : serial8250_interrupt() : __handle_irq_event_percpu() : handle_irq_event_percpu() : handle_irq_event() : handle_level_irq() : handle_irq() : do_IRQ() : ret_from_intr() : native_safe_halt() : default_idle() : arch_cpu_idle() : default_idle_call() : do_idle() : cpu_startup_entry() : rest_init() : start_kernel() : x86_64_start_reservations() : x86_64_start_kernel() : verify_cpu() : : -> #1 (&tty->write_wait){-.-.}: : __lock_acquire() : lock_acquire() : _raw_spin_lock_irqsave() : __wake_up_common_lock() : __wake_up() : tty_wakeup() : tty_port_default_wakeup() : tty_port_tty_wakeup() : uart_write_wakeup() : serial8250_tx_chars() : serial8250_handle_irq.part.25() : serial8250_default_handle_irq() : serial8250_interrupt() : __handle_irq_event_percpu() : handle_irq_event_percpu() : handle_irq_event() : handle_level_irq() : handle_irq() : do_IRQ() : ret_from_intr() : native_safe_halt() : default_idle() : arch_cpu_idle() : default_idle_call() : do_idle() : cpu_startup_entry() : rest_init() : start_kernel() : x86_64_start_reservations() : x86_64_start_kernel() : verify_cpu() : : -> #0 (&port_lock_key){-.-.}: : check_prev_add() : __lock_acquire() : lock_acquire() : _raw_spin_lock_irqsave() : serial8250_console_write() : univ8250_console_write() : console_unlock() : vprintk_emit() : vprintk_default() : vprintk_func() : printk() : ___ratelimit() : __printk_ratelimit() : select_fallback_rq() : sched_cpu_dying() : cpuhp_invoke_callback() : take_cpu_down() : multi_cpu_stop() : cpu_stopper_thread() : smpboot_thread_fn() : kthread() : ret_from_fork() : : other info that might help us debug this: : : Chain exists of: : &port_lock_key --> &p->pi_lock --> &rq->lock : : Possible unsafe locking scenario: : : CPU0 CPU1 : ---- ---- : lock(&rq->lock); : lock(&p->pi_lock); : lock(&rq->lock); : lock(&port_lock_key); : : *** DEADLOCK *** : : 4 locks held by migration/8/62: : #0: (&p->pi_lock){-.-.}, at: sched_cpu_dying() : #1: (&rq->lock){-.-.}, at: sched_cpu_dying() : #2: (printk_ratelimit_state.lock){....}, at: ___ratelimit() : #3: (console_lock){+.+.}, at: vprintk_emit() : : stack backtrace: : CPU: 8 PID: 62 Comm: migration/8 Not tainted 4.14.0-rc2-next-20170927+ #252 : Call Trace: : dump_stack() : print_circular_bug() : check_prev_add() : ? add_lock_to_list.isra.26() : ? check_usage() : ? kvm_clock_read() : ? kvm_sched_clock_read() : ? sched_clock() : ? check_preemption_disabled() : __lock_acquire() : ? __lock_acquire() : ? add_lock_to_list.isra.26() : ? debug_check_no_locks_freed() : ? memcpy() : lock_acquire() : ? serial8250_console_write() : _raw_spin_lock_irqsave() : ? serial8250_console_write() : serial8250_console_write() : ? serial8250_start_tx() : ? lock_acquire() : ? memcpy() : univ8250_console_write() : console_unlock() : ? __down_trylock_console_sem() : vprintk_emit() : vprintk_default() : vprintk_func() : printk() : ? show_regs_print_info() : ? lock_acquire() : ___ratelimit() : __printk_ratelimit() : select_fallback_rq() : sched_cpu_dying() : ? sched_cpu_starting() : ? rcutree_dying_cpu() : ? sched_cpu_starting() : cpuhp_invoke_callback() : ? cpu_disable_common() : take_cpu_down() : ? trace_hardirqs_off_caller() : ? cpuhp_invoke_callback() : multi_cpu_stop() : ? __this_cpu_preempt_check() : ? cpu_stop_queue_work() : cpu_stopper_thread() : ? cpu_stop_create() : smpboot_thread_fn() : ? sort_range() : ? schedule() : ? __kthread_parkme() : kthread() : ? sort_range() : ? kthread_create_on_node() : ret_from_fork() : process 9121 (trinity-c78) no longer affine to cpu8 : smpboot: CPU 8 is now offline Link: http://lkml.kernel.org/r/20170928120405.18273-1-sergey.senozhatsky@gmail.com Fixes: 6b1d174b0c27b ("ratelimit: extend to print suppressed messages on release") Signed-off-by: Sergey Senozhatsky Reported-by: Sasha Levin Reviewed-by: Petr Mladek Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Steven Rostedt Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/ratelimit.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/ratelimit.c b/lib/ratelimit.c index 08f8043cac61..d01f47135239 100644 --- a/lib/ratelimit.c +++ b/lib/ratelimit.c @@ -48,7 +48,9 @@ int ___ratelimit(struct ratelimit_state *rs, const char *func) if (time_is_before_jiffies(rs->begin + rs->interval)) { if (rs->missed) { if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE)) { - pr_warn("%s: %d callbacks suppressed\n", func, rs->missed); + printk_deferred(KERN_WARNING + "%s: %d callbacks suppressed\n", + func, rs->missed); rs->missed = 0; } } -- cgit v1.2.3