diff options
Diffstat (limited to 'Documentation/sysctl')
-rw-r--r-- | Documentation/sysctl/fs.txt | 36 | ||||
-rw-r--r-- | Documentation/sysctl/kernel.txt | 29 | ||||
-rw-r--r-- | Documentation/sysctl/vm.txt | 25 |
3 files changed, 87 insertions, 3 deletions
diff --git a/Documentation/sysctl/fs.txt b/Documentation/sysctl/fs.txt index 6c00c1e2743f..819caf8ca05f 100644 --- a/Documentation/sysctl/fs.txt +++ b/Documentation/sysctl/fs.txt @@ -34,7 +34,9 @@ Currently, these files are in /proc/sys/fs: - overflowgid - pipe-user-pages-hard - pipe-user-pages-soft +- protected_fifos - protected_hardlinks +- protected_regular - protected_symlinks - suid_dumpable - super-max @@ -182,6 +184,24 @@ applied. ============================================================== +protected_fifos: + +The intent of this protection is to avoid unintentional writes to +an attacker-controlled FIFO, where a program expected to create a regular +file. + +When set to "0", writing to FIFOs is unrestricted. + +When set to "1" don't allow O_CREAT open on FIFOs that we don't own +in world writable sticky directories, unless they are owned by the +owner of the directory. + +When set to "2" it also applies to group writable sticky directories. + +This protection is based on the restrictions in Openwall. + +============================================================== + protected_hardlinks: A long-standing class of security issues is the hardlink-based @@ -202,6 +222,22 @@ This protection is based on the restrictions in Openwall and grsecurity. ============================================================== +protected_regular: + +This protection is similar to protected_fifos, but it +avoids writes to an attacker-controlled regular file, where a program +expected to create one. + +When set to "0", writing to regular files is unrestricted. + +When set to "1" don't allow O_CREAT open on regular files that we +don't own in world writable sticky directories, unless they are +owned by the owner of the directory. + +When set to "2" it also applies to group writable sticky directories. + +============================================================== + protected_symlinks: A long-standing class of security issues is the symlink-based diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index eded671d55eb..37a679501ddc 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -38,7 +38,9 @@ show up in /proc/sys/kernel: - hung_task_panic - hung_task_check_count - hung_task_timeout_secs +- hung_task_check_interval_secs - hung_task_warnings +- hyperv_record_panic_msg - kexec_load_disabled - kptr_restrict - l2cr [ PPC only ] @@ -354,7 +356,7 @@ This file shows up if CONFIG_DETECT_HUNG_TASK is enabled. hung_task_timeout_secs: -Check interval. When a task in D state did not get scheduled +When a task in D state did not get scheduled for more than this value report a warning. This file shows up if CONFIG_DETECT_HUNG_TASK is enabled. @@ -363,6 +365,18 @@ Possible values to set are in range {0..LONG_MAX/HZ}. ============================================================== +hung_task_check_interval_secs: + +Hung task check interval. If hung task checking is enabled +(see hung_task_timeout_secs), the check is done every +hung_task_check_interval_secs seconds. +This file shows up if CONFIG_DETECT_HUNG_TASK is enabled. + +0 (default): means use hung_task_timeout_secs as checking interval. +Possible values to set are in range {0..LONG_MAX/HZ}. + +============================================================== + hung_task_warnings: The maximum number of warnings to report. During a check interval @@ -374,6 +388,16 @@ This file shows up if CONFIG_DETECT_HUNG_TASK is enabled. ============================================================== +hyperv_record_panic_msg: + +Controls whether the panic kmsg data should be reported to Hyper-V. + +0: do not report panic kmsg data. + +1: report the panic kmsg data. This is the default behavior. + +============================================================== + kexec_load_disabled: A toggle indicating if the kexec_load syscall has been disabled. This @@ -440,7 +464,8 @@ Notes: 1) kernel doesn't guarantee, that new object will have desired id. So, it's up to userspace, how to handle an object with "wrong" id. 2) Toggle with non-default value will be set back to -1 by kernel after -successful IPC object allocation. +successful IPC object allocation. If an IPC object allocation syscall +fails, it is undefined if the value remains unmodified or is reset to -1. ============================================================== diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 697ef8c225df..7d73882e2c27 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -27,6 +27,7 @@ Currently, these files are in /proc/sys/vm: - dirty_bytes - dirty_expire_centisecs - dirty_ratio +- dirtytime_expire_seconds - dirty_writeback_centisecs - drop_caches - extfrag_threshold @@ -44,6 +45,7 @@ Currently, these files are in /proc/sys/vm: - mmap_rnd_bits - mmap_rnd_compat_bits - nr_hugepages +- nr_hugepages_mempolicy - nr_overcommit_hugepages - nr_trim_pages (only if CONFIG_MMU=n) - numa_zonelist_order @@ -178,6 +180,18 @@ The total available memory is not equal to total system memory. ============================================================== +dirtytime_expire_seconds + +When a lazytime inode is constantly having its pages dirtied, the inode with +an updated timestamp will never get chance to be written out. And, if the +only thing that has happened on the file system is a dirtytime inode caused +by an atime update, a worker will be scheduled to make sure that inode +eventually gets pushed out to disk. This tunable is used to define when dirty +inode is old enough to be eligible for writeback by the kernel flusher threads. +And, it is also used as the interval to wakeup dirtytime_writeback thread. + +============================================================== + dirty_writeback_centisecs The kernel flusher threads will periodically wake up and write `old' data @@ -519,6 +533,15 @@ See Documentation/admin-guide/mm/hugetlbpage.rst ============================================================== +nr_hugepages_mempolicy + +Change the size of the hugepage pool at run-time on a specific +set of NUMA nodes. + +See Documentation/admin-guide/mm/hugetlbpage.rst + +============================================================== + nr_overcommit_hugepages Change the maximum size of the hugepage pool. The maximum is @@ -668,7 +691,7 @@ and don't use much of it. The default value is 0. See Documentation/vm/overcommit-accounting.rst and -mm/mmap.c::__vm_enough_memory() for more information. +mm/util.c::__vm_enough_memory() for more information. ============================================================== |