From 140588bfed2727e9a4814211617a79401d74922f Mon Sep 17 00:00:00 2001 From: Stephen Kitt Date: Fri, 14 Feb 2020 18:26:28 +0100 Subject: s390: remove obsolete ieee_emulation_warnings s390 math emulation was removed with commit 5a79859ae0f3 ("s390: remove 31 bit support"), rendering ieee_emulation_warnings useless. The code still built because it was protected by CONFIG_MATHEMU, which was no longer selectable. This patch removes the sysctl_ieee_emulation_warnings declaration and the sysctl entry declaration. Link: https://lkml.kernel.org/r/20200214172628.3598516-1-steve@sk2.org Reviewed-by: Vasily Gorbik Signed-off-by: Stephen Kitt Signed-off-by: Vasily Gorbik --- kernel/sysctl.c | 9 --------- 1 file changed, 9 deletions(-) (limited to 'kernel/sysctl.c') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index d396aaaf19a3..ad5b88a53c5a 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -805,15 +805,6 @@ static struct ctl_table kern_table[] = { .extra2 = &maxolduid, }, #ifdef CONFIG_S390 -#ifdef CONFIG_MATHEMU - { - .procname = "ieee_emulation_warnings", - .data = &sysctl_ieee_emulation_warnings, - .maxlen = sizeof(int), - .mode = 0644, - .proc_handler = proc_dointvec, - }, -#endif { .procname = "userprocess_debug", .data = &show_unhandled_signals, -- cgit v1.2.3 From eaee41727e6d8a7d2b94421c25e82b00cb2fded5 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 2 Mar 2020 17:51:34 +0000 Subject: sysctl/sysrq: Remove __sysrq_enabled copy Many embedded boards have a disconnected TTL level serial which can generate some garbage that can lead to spurious false sysrq detects. Currently, sysrq can be either completely disabled for serial console or always disabled (with CONFIG_MAGIC_SYSRQ_SERIAL), since commit 732dbf3a6104 ("serial: do not accept sysrq characters via serial port") At Arista, we have such boards that can generate BREAK and random garbage. While disabling sysrq for serial console would solve the problem with spurious false sysrq triggers, it's also desirable to have a way to enable sysrq back. Having the way to enable sysrq was beneficial to debug lockups with a manual investigation in field and on the other side preventing false sysrq detections. As a preparation to add sysrq_toggle_support() call into uart, remove a private copy of sysrq_enabled from sysctl - it should reflect the actual status of sysrq. Furthermore, the private copy isn't correct already in case sysrq_always_enabled is true. So, remove __sysrq_enabled and use a getter-helper sysrq_mask() to check sysrq_key_op enabled status. Cc: Iurii Zaikin Cc: Jiri Slaby Cc: Luis Chamberlain Cc: Kees Cook Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Dmitry Safonov Link: https://lore.kernel.org/r/20200302175135.269397-2-dima@arista.com Signed-off-by: Greg Kroah-Hartman --- kernel/sysctl.c | 41 ++++++++++++++++++++++------------------- 1 file changed, 22 insertions(+), 19 deletions(-) (limited to 'kernel/sysctl.c') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index ad5b88a53c5a..94638f695e60 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -229,25 +229,8 @@ static int proc_dopipe_max_size(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); #ifdef CONFIG_MAGIC_SYSRQ -/* Note: sysrq code uses its own private copy */ -static int __sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE; - static int sysrq_sysctl_handler(struct ctl_table *table, int write, - void __user *buffer, size_t *lenp, - loff_t *ppos) -{ - int error; - - error = proc_dointvec(table, write, buffer, lenp, ppos); - if (error) - return error; - - if (write) - sysrq_toggle_support(__sysrq_enabled); - - return 0; -} - + void __user *buffer, size_t *lenp, loff_t *ppos); #endif static struct ctl_table kern_table[]; @@ -747,7 +730,7 @@ static struct ctl_table kern_table[] = { #ifdef CONFIG_MAGIC_SYSRQ { .procname = "sysrq", - .data = &__sysrq_enabled, + .data = NULL, .maxlen = sizeof (int), .mode = 0644, .proc_handler = sysrq_sysctl_handler, @@ -2835,6 +2818,26 @@ static int proc_dostring_coredump(struct ctl_table *table, int write, } #endif +#ifdef CONFIG_MAGIC_SYSRQ +static int sysrq_sysctl_handler(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + int tmp, ret; + + tmp = sysrq_mask(); + + ret = __do_proc_dointvec(&tmp, table, write, buffer, + lenp, ppos, NULL, NULL); + if (ret || !write) + return ret; + + if (write) + sysrq_toggle_support(tmp); + + return 0; +} +#endif + static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos, -- cgit v1.2.3 From 964b692daf3018ae4b45285c3bcbb2d897cb4b40 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Wed, 1 Apr 2020 21:10:38 -0700 Subject: mm/compaction: really limit compact_unevictable_allowed to 0 and 1 The proc file `compact_unevictable_allowed' should allow 0 and 1 only, the `extra*' attribues have been set properly but without proc_dointvec_minmax() as the `proc_handler' the limit will not be enforced. Use proc_dointvec_minmax() as the `proc_handler' to enfoce the valid specified range. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Andrew Morton Reviewed-by: Andrew Morton Acked-by: Vlastimil Babka Cc: Thomas Gleixner Cc: Luis Chamberlain Cc: Kees Cook Cc: Iurii Zaikin Cc: Mel Gorman Link: http://lkml.kernel.org/r/20200303202054.gsosv7fsx2ma3cic@linutronix.de Signed-off-by: Linus Torvalds --- kernel/sysctl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/sysctl.c') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 94638f695e60..cb650bb9da68 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1467,7 +1467,7 @@ static struct ctl_table vm_table[] = { .data = &sysctl_compact_unevictable_allowed, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec, + .proc_handler = proc_dointvec_minmax, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, }, -- cgit v1.2.3 From 6923aa0d8c629a7853822626877dcb11f4f1d354 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Wed, 1 Apr 2020 21:10:42 -0700 Subject: mm/compaction: Disable compact_unevictable_allowed on RT Since commit 5bbe3547aa3ba ("mm: allow compaction of unevictable pages") it is allowed to examine mlocked pages and compact them by default. On -RT even minor pagefaults are problematic because it may take a few 100us to resolve them and until then the task is blocked. Make compact_unevictable_allowed = 0 default and issue a warning on RT if it is changed. [bigeasy@linutronix.de: v5] Link: https://lore.kernel.org/linux-mm/20190710144138.qyn4tuttdq6h7kqx@linutronix.de/ Link: http://lkml.kernel.org/r/20200319165536.ovi75tsr2seared4@linutronix.de Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Andrew Morton Reviewed-by: Andrew Morton Acked-by: Mel Gorman Acked-by: Vlastimil Babka Cc: Thomas Gleixner Cc: Luis Chamberlain Cc: Kees Cook Cc: Iurii Zaikin Cc: Vlastimil Babka Link: https://lore.kernel.org/linux-mm/20190710144138.qyn4tuttdq6h7kqx@linutronix.de/ Link: http://lkml.kernel.org/r/20200303202225.nhqc3v5gwlb7x6et@linutronix.de Signed-off-by: Linus Torvalds --- kernel/sysctl.c | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) (limited to 'kernel/sysctl.c') diff --git a/kernel/sysctl.c b/kernel/sysctl.c index cb650bb9da68..8a176d8727a3 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -212,6 +212,11 @@ static int proc_do_cad_pid(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); static int proc_taint(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); +#ifdef CONFIG_COMPACTION +static int proc_dointvec_minmax_warn_RT_change(struct ctl_table *table, + int write, void __user *buffer, + size_t *lenp, loff_t *ppos); +#endif #endif #ifdef CONFIG_PRINTK @@ -1467,7 +1472,7 @@ static struct ctl_table vm_table[] = { .data = &sysctl_compact_unevictable_allowed, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec_minmax, + .proc_handler = proc_dointvec_minmax_warn_RT_change, .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_ONE, }, @@ -2555,6 +2560,28 @@ int proc_dointvec(struct ctl_table *table, int write, return do_proc_dointvec(table, write, buffer, lenp, ppos, NULL, NULL); } +#ifdef CONFIG_COMPACTION +static int proc_dointvec_minmax_warn_RT_change(struct ctl_table *table, + int write, void __user *buffer, + size_t *lenp, loff_t *ppos) +{ + int ret, old; + + if (!IS_ENABLED(CONFIG_PREEMPT_RT) || !write) + return proc_dointvec_minmax(table, write, buffer, lenp, ppos); + + old = *(int *)table->data; + ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + if (ret) + return ret; + if (old != *(int *)table->data) + pr_warn_once("sysctl attribute %s changed by %s[%d]\n", + table->procname, current->comm, + task_pid_nr(current)); + return ret; +} +#endif + /** * proc_douintvec - read a vector of unsigned integers * @table: the sysctl table -- cgit v1.2.3