user/sven/linux.git/kernel/sysctl.c, branch v2.6.37.2

Input: sysrq - ensure sysrq_enabled and __sysrq_enabled are consistent

2011-02-17T23:15:07Z

commit 8c6a98b22b750c9eb52653ba643faa17db8d3881 upstream. Currently sysrq_enabled and __sysrq_enabled are initialised separately and inconsistently, leading to sysrq being actually enabled by reported as not enabled in sysfs. The first change to the sysfs configurable synchronises these two: static int __read_mostly sysrq_enabled = 1; static int __sysrq_enabled; Add a common define to carry the default for these preventing them becoming out of sync again. Default this to 1 to mirror previous behaviour. Signed-off-by: Andy Whitcroft Signed-off-by: Dmitry Torokhov Signed-off-by: Greg Kroah-Hartman

kernel/sysctl.c: Fix build failure with !CONFIG_PRINTK

2010-11-16T15:56:09Z

Sigh... Signed-off-by: Joe Perches Acked-by: Eric Paris Signed-off-by: Linus Torvalds

Restrict unprivileged access to kernel syslog

2010-11-12T15:55:32Z

The kernel syslog contains debugging information that is often useful during exploitation of other vulnerabilities, such as kernel heap addresses. Rather than futilely attempt to sanitize hundreds (or thousands) of printk statements and simultaneously cripple useful debugging functionality, it is far simpler to create an option that prevents unprivileged users from reading the syslog. This patch, loosely based on grsecurity's GRKERNSEC_DMESG, creates the dmesg_restrict sysctl. When set to "0", the default, no restrictions are enforced. When set to "1", only users with CAP_SYS_ADMIN can read the kernel syslog via dmesg(8) or other mechanisms. [akpm@linux-foundation.org: explain the config option in kernel.txt] Signed-off-by: Dan Rosenberg Acked-by: Ingo Molnar Acked-by: Eugene Teo Acked-by: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6

2010-10-27T00:58:44Z

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (52 commits) split invalidate_inodes() fs: skip I_FREEING inodes in writeback_sb_inodes fs: fold invalidate_list into invalidate_inodes fs: do not drop inode_lock in dispose_list fs: inode split IO and LRU lists fs: switch bdev inode bdi's correctly fs: fix buffer invalidation in invalidate_list fsnotify: use dget_parent smbfs: use dget_parent exportfs: use dget_parent fs: use RCU read side protection in d_validate fs: clean up dentry lru modification fs: split __shrink_dcache_sb fs: improve DCACHE_REFERENCED usage fs: use percpu counter for nr_dentry and nr_dentry_unused fs: simplify __d_free fs: take dcache_lock inside __d_path fs: do not assign default i_ino in new_inode fs: introduce a per-cpu last_ino allocator new helper: ihold() ...

printk: declare printk_ratelimit_state in ratelimit.h

2010-10-26T23:52:16Z

Adding declaration of printk_ratelimit_state in ratelimit.h removes potential build breakage and following sparse warning: kernel/printk.c:1426:1: warning: symbol 'printk_ratelimit_state' was not declared. Should it be static? [akpm@linux-foundation.org: remove unneeded ifdef] Signed-off-by: Namhyung Kim Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fs: allow for more than 2^31 files

2010-10-26T23:52:15Z

Robin Holt tried to boot a 16TB system and found af_unix was overflowing a 32bit value : We were seeing a failure which prevented boot. The kernel was incapable of creating either a named pipe or unix domain socket. This comes down to a common kernel function called unix_create1() which does: atomic_inc(&unix_nr_socks); if (atomic_read(&unix_nr_socks) > 2 * get_max_files()) goto out; The function get_max_files() is a simple return of files_stat.max_files. files_stat.max_files is a signed integer and is computed in fs/file_table.c's files_init(). n = (mempages * (PAGE_SIZE / 1024)) / 10; files_stat.max_files = n; In our case, mempages (total_ram_pages) is approx 3,758,096,384 (0xe0000000). That leaves max_files at approximately 1,503,238,553. This causes 2 * get_max_files() to integer overflow. Fix is to let /proc/sys/fs/file-nr & /proc/sys/fs/file-max use long integers, and change af_unix to use an atomic_long_t instead of atomic_t. get_max_files() is changed to return an unsigned long. get_nr_files() is changed to return a long. unix_nr_socks is changed from atomic_t to atomic_long_t, while not strictly needed to address Robin problem. Before patch (on a 64bit kernel) : # echo 2147483648 >/proc/sys/fs/file-max # cat /proc/sys/fs/file-max -18446744071562067968 After patch: # echo 2147483648 >/proc/sys/fs/file-max # cat /proc/sys/fs/file-max 2147483648 # cat /proc/sys/fs/file-nr 704 0 2147483648 Reported-by: Robin Holt Signed-off-by: Eric Dumazet Acked-by: David Miller Reviewed-by: Robin Holt Tested-by: Robin Holt Cc: Al Viro Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fs: use percpu counter for nr_dentry and nr_dentry_unused

2010-10-26T01:26:12Z

The nr_dentry stat is a globally touched cacheline and atomic operation twice over the lifetime of a dentry. It is used for the benfit of userspace only. Turn it into a per-cpu counter and always decrement it in d_free instead of doing various batching operations to reduce lock hold times in the callers. Based on an earlier patch from Nick Piggin . Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

fs: Convert nr_inodes and nr_unused to per-cpu counters

2010-10-26T01:26:09Z

The number of inodes allocated does not need to be tied to the addition or removal of an inode to/from a list. If we are not tied to a list lock, we could update the counters when inodes are initialised or destroyed, but to do that we need to convert the counters to be per-cpu (i.e. independent of a lock). This means that we have the freedom to change the list/locking implementation without needing to care about the counters. Based on a patch originally from Eric Dumazet. [AV: cleaned up a bit, fixed build breakage on weird configs Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Al Viro

fs: allow for more than 2^31 files

2010-10-26T01:18:20Z

Andrew, Could you please review this patch, you probably are the right guy to take it, because it crosses fs and net trees. Note : /proc/sys/fs/file-nr is a read-only file, so this patch doesnt depend on previous patch (sysctl: fix min/max handling in __do_proc_doulongvec_minmax()) Thanks ! [PATCH V4] fs: allow for more than 2^31 files Robin Holt tried to boot a 16TB system and found af_unix was overflowing a 32bit value : We were seeing a failure which prevented boot. The kernel was incapable of creating either a named pipe or unix domain socket. This comes down to a common kernel function called unix_create1() which does: atomic_inc(&unix_nr_socks); if (atomic_read(&unix_nr_socks) > 2 * get_max_files()) goto out; The function get_max_files() is a simple return of files_stat.max_files. files_stat.max_files is a signed integer and is computed in fs/file_table.c's files_init(). n = (mempages * (PAGE_SIZE / 1024)) / 10; files_stat.max_files = n; In our case, mempages (total_ram_pages) is approx 3,758,096,384 (0xe0000000). That leaves max_files at approximately 1,503,238,553. This causes 2 * get_max_files() to integer overflow. Fix is to let /proc/sys/fs/file-nr & /proc/sys/fs/file-max use long integers, and change af_unix to use an atomic_long_t instead of atomic_t. get_max_files() is changed to return an unsigned long. get_nr_files() is changed to return a long. unix_nr_socks is changed from atomic_t to atomic_long_t, while not strictly needed to address Robin problem. Before patch (on a 64bit kernel) : # echo 2147483648 >/proc/sys/fs/file-max # cat /proc/sys/fs/file-max -18446744071562067968 After patch: # echo 2147483648 >/proc/sys/fs/file-max # cat /proc/sys/fs/file-max 2147483648 # cat /proc/sys/fs/file-nr 704 0 2147483648 Reported-by: Robin Holt Signed-off-by: Eric Dumazet Acked-by: David Miller Reviewed-by: Robin Holt Tested-by: Robin Holt Signed-off-by: Al Viro

sysctl: fix min/max handling in __do_proc_doulongvec_minmax()

2010-10-07T20:31:21Z

When proc_doulongvec_minmax() is used with an array of longs, and no min/max check requested (.extra1 or .extra2 being NULL), we dereference a NULL pointer for the second element of the array. Noticed while doing some changes in network stack for the "16TB problem" Fix is to not change min & max pointers in __do_proc_doulongvec_minmax(), so that all elements of the vector share an unique min/max limit, like proc_dointvec_minmax(). [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Eric Dumazet Cc: "Eric W. Biederman" Cc: Americo Wang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds