Enable security modules to distinguish reading of process state via
proc from full ptrace access by renaming ptrace_may_attach to
ptrace_may_access and adding a mode argument indicating whether only
read access or full attach access is requested. This allows security
modules to permit access to reading process state without granting
full ptrace access. The base DAC/capability checking remains unchanged.
Read access to /proc/pid/mem continues to apply a full ptrace attach
check since check_mem_permission() already requires the current task
to already be ptracing the target. The other ptrace checks within
proc for elements like environ, maps, and fds are changed to pass the
read mode instead of attach.
In the SELinux case, we model such reading of process state as a
reading of a proc file labeled with the target process' label. This
enables SELinux policy to permit such reading of process state without
permitting control or manipulation of the target process, as there are
a number of cases where programs probe for such information via proc
but do not need to be able to control the target (e.g. procps,
lsof, PolicyKit, ConsoleKit). At present we have to choose between
allowing full ptrace in policy (more permissive than required/desired)
or breaking functionality (or in some cases just silencing the denials
via dontaudit rules but this can hide genuine attacks).
This version of the patch incorporates comments from Casey Schaufler
(change/replace existing ptrace_may_attach interface, pass access
mode), and Chris Wright (provide greater consistency in the checking).
Note that like their predecessors __ptrace_may_attach and
ptrace_may_attach, the __ptrace_may_access and ptrace_may_access
interfaces use different return value conventions from each other (0
or -errno vs. 1 or 0). I retained this difference to avoid any
changes to the caller logic but made the difference clearer by
changing the latter interface to return a bool rather than an int and
by adding a comment about it to ptrace.h for any future callers.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: James Morris <jmorris@namei.org>
Remove inherit field from inode_security_struct, per Stephen Smalley:
"Let's just drop inherit altogether - dead field."
Signed-off-by: James Morris <jmorris@namei.org>
reorder inode_security_struct to remove padding on 64 bit builds
size reduced from 72 to 64 bytes increasing objects per slab to 64.
Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: James Morris <jmorris@namei.org>
Formatting and syntax changes
whitespace, tabs to spaces, trailing space
put open { on same line as struct def
remove unneeded {} after if statements
change printk("Lu") to printk("llu")
convert asm/uaccess.h to linux/uaacess.h includes
remove unnecessary asm/bug.h includes
convert all users of simple_strtol to strict_strtol
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
Fix a sleeping function called from invalid context bug by moving allocation
to the callers prior to taking the policy rdlock.
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Introduce SELinux support for deferred mapping of security contexts in
the SID table upon policy reload, and use this support for inode
security contexts when the context is not yet valid under the current
policy. Only processes with CAP_MAC_ADMIN + mac_admin permission in
policy can set undefined security contexts on inodes. Inodes with
such undefined contexts are treated as having the unlabeled context
until the context becomes valid upon a policy reload that defines the
context. Context invalidation upon policy reload also uses this
support to save the context information in the SID table and later
recover it upon a subsequent policy reload that defines the context
again.
This support is to enable package managers and similar programs to set
down file contexts unknown to the system policy at the time the file
is created in order to better support placing loadable policy modules
in packages and to support build systems that need to create images of
different distro releases with different policies w/o requiring all of
the contexts to be defined or legal in the build host policy.
With this patch applied, the following sequence is possible, although
in practice it is recommended that this permission only be allowed to
specific program domains such as the package manager.
# rmdir baz
# rm bar
# touch bar
# chcon -t foo_exec_t bar # foo_exec_t is not yet defined
chcon: failed to change context of `bar' to `system_u:object_r:foo_exec_t': Invalid argument
# mkdir -Z system_u:object_r:foo_exec_t baz
mkdir: failed to set default file creation context to `system_u:object_r:foo_exec_t': Invalid argument
# cat setundefined.te
policy_module(setundefined, 1.0)
require {
type unconfined_t;
type unlabeled_t;
}
files_type(unlabeled_t)
allow unconfined_t self:capability2 mac_admin;
# make -f /usr/share/selinux/devel/Makefile setundefined.pp
# semodule -i setundefined.pp
# chcon -t foo_exec_t bar # foo_exec_t is not yet defined
# mkdir -Z system_u:object_r:foo_exec_t baz
# ls -Zd bar baz
-rw-r--r-- root root system_u:object_r:unlabeled_t bar
drwxr-xr-x root root system_u:object_r:unlabeled_t baz
# cat foo.te
policy_module(foo, 1.0)
type foo_exec_t;
files_type(foo_exec_t)
# make -f /usr/share/selinux/devel/Makefile foo.pp
# semodule -i foo.pp # defines foo_exec_t
# ls -Zd bar baz
-rw-r--r-- root root user_u:object_r:foo_exec_t bar
drwxr-xr-x root root system_u:object_r:foo_exec_t baz
# semodule -r foo
# ls -Zd bar baz
-rw-r--r-- root root system_u:object_r:unlabeled_t bar
drwxr-xr-x root root system_u:object_r:unlabeled_t baz
# semodule -i foo.pp
# ls -Zd bar baz
-rw-r--r-- root root user_u:object_r:foo_exec_t bar
drwxr-xr-x root root system_u:object_r:foo_exec_t baz
# semodule -r setundefined foo
# chcon -t foo_exec_t bar # no longer defined and not allowed
chcon: failed to change context of `bar' to `system_u:object_r:foo_exec_t': Invalid argument
# rmdir baz
# mkdir -Z system_u:object_r:foo_exec_t baz
mkdir: failed to set default file creation context to `system_u:object_r:foo_exec_t': Invalid argument
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
# cat devices.list
c 1:3 r
# echo 'c 1:3 w' > sub/devices.allow
# cat sub/devices.list
c 1:3 w
As illustrated, the parent group has no write permission to /dev/null, so
it's child should not be allowed to add this write permission.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# echo "b $((0x7fffffff)):$((0x80000000)) rwm" > devices.allow
# cat devices.list
b 214748364:-21474836 rwm
though a major/minor number of 0x800000000 is meaningless, we
should not cast it to a negative value.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit f18f982ab ("sched: CPU hotplug events must not destroy scheduler
domains created by the cpusets") introduced a hotplug-related problem as
described below:
Upon CPU_DOWN_PREPARE,
update_sched_domains() -> detach_destroy_domains(&cpu_online_map)
does the following:
/*
* Force a reinitialization of the sched domains hierarchy. The domains
* and groups cannot be updated in place without racing with the balancing
* code, so we temporarily attach all running cpus to the NULL domain
* which will prevent rebalancing while the sched domains are recalculated.
*/
The sched-domains should be rebuilt when a CPU_DOWN ops. has been
completed, effectively either upon CPU_DEAD{_FROZEN} (upon success) or
CPU_DOWN_FAILED{_FROZEN} (upon failure -- restore the things to their
initial state). That's what update_sched_domains() also does but only
for !CPUSETS case.
With f18f982ab, sched-domains' reinitialization is delegated to
CPUSETS code:
cpuset_handle_cpuhp() -> common_cpu_mem_hotplug_unplug() ->
rebuild_sched_domains()
Being called for CPU_UP_PREPARE and if its callback is called after
update_sched_domains()), it just negates all the work done by
update_sched_domains() -- i.e. a soon-to-be-offline cpu is included in
the sched-domains and that makes it visible for the load-balancer
while the CPU_DOWN ops. is in progress.
__migrate_live_tasks() moves the tasks off a 'dead' cpu (it's already
"offline" when this function is called).
try_to_wake_up() is called for one of these tasks from another CPU ->
the load-balancer (wake_idle()) picks up a "dead" CPU and places the
task on it. Then e.g. BUG_ON(rq->nr_running) detects this a bit later
-> oops.
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Tested-by: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Paul Menage <menage@google.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: miaox@cn.fujitsu.com
Cc: rostedt@goodmis.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6:
[SCSI] bsg: fix oops on remove
[SCSI] fusion: default MSI to disabled for SPI and FC controllers
[SCSI] ipr: Fix HDIO_GET_IDENTITY oops for SATA devices
[SCSI] mptspi: fix oops in mptspi_dv_renegotiate_work()
[SCSI] erase invalid data returned by device
The current definition of wksidarr works fine on little endian arches
(since cpu_to_le32 is a no-op there), but on big-endian arches, it fails
to compile with this error:
error: braced-group within expression allowed only inside a function
The problem is that this static declaration has cpu_to_le32 embedded
within it, and that expands into a function macro. We need to use
__constant_cpu_to_le32() instead.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: Steven French <sfrench@us.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Try this:
mount a share with unix extensions
create a file on it
umount the share
You'll get the following message in the ring buffer:
VFS: Busy inodes after unmount of cifs. Self-destruct in 5 seconds. Have a
nice day...
...the problem is that cifs_get_inode_info_unix is creating and hashing
a new inode even when it's going to return error anyway. The first
lookup when creating a file returns an error so we end up leaking this
inode before we do the actual create. This appears to be a regression
caused by commit 0e4bbde94f.
The following patch seems to fix it for me, and fixes a minor
formatting nit as well.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix FRV irqs_disabled() to return an int, not an unsigned long to avoid
this warning:
kernel/sched.c: In function '__might_sleep':
kernel/sched.c:8198: warning: format '%d' expects type 'int', but argument 3 has type 'long unsigned int'
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Philippe Elie <phil.el@wanadoo.fr>
Cc: John Levon <levon@movementarian.org>
Cc: Maynard Johnson <maynardj@us.ibm.com>
Cc: Richard Purdie <rpurdie@openedhand.com>
Cc: Daniel Hansel <daniel.hansel@linux.vnet.ibm.com>
Cc: Jason Yeh <jason.yeh@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cortland Setlow pointed out a bug in ov7670.c where the result from
ov7670_read() was just being checked for !0, rather than <0. This made me
realize that ov7670_read's semantics were rather confusing; it both fills
in 'value' with the result, and returns it. This is goes against general
kernel convention; so rather than fixing callers, let's fix the function.
This makes ov7670_read return <0 in the case of an error, and 0 upon
success. Thus, code like:
res = ov7670_read(...);
if (!res)
goto error;
..will work properly.
Signed-off-by: Cortland Setlow <csetlow@tower-research.com>
Signed-off-by: Andres Salomon <dilinger@debian.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I had 8250.nr_uarts=16 in the boot line of a test kernel and I had a weird
mysterious crash in sysfs. After taking an in-depth look I realized that
CONFIG_SERIAL_8250_NR_UARTS was set to 4 and I was walking off the end of
the serial8250_ports array.
Ouch!!!
Don't let this happen to someone else.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Alan Cox <alan@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is a bugfix for how defio handles multiple processes manipulating
the same framebuffer.
Thanks to Bernard Blackham for identifying this bug.
It occurs when two applications mmap the same framebuffer and concurrently
write to the same page. Normally, this doesn't occur since only a single
process mmaps the framebuffer. The symptom of the bug is that the mapping
applications will hang. The cause is that defio incorrectly tries to add the
same page twice to the pagelist. The solution I have is to walk the pagelist
and check for a duplicate before adding. Since I needed to walk the pagelist,
I now also keep the pagelist in sorted order.
Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Cc: Bernard Blackham <bernard@largestprime.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Coverity CID: 1356 RESOURCE_LEAK
I found a very old patch for this that was Acked but did not get applied
https://lists.linux-foundation.org/pipermail/kernel-janitors/2006-September/016362.html
There looks to be a small leak in isdn_writebuf_stub() in isdn_common.c, when
copy_from_user() returns an un-copied data length (length != 0). The below
patch should be a minimally invasive fix.
Signed-off-by: Darren Jenkins <darrenrjenkins@gmailcom>
Acked-by: Karsten Keil <kkeil@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Coverity CID: 2172 RESOURCE_LEAK
When pool_allocate() tries to enlarge a packet, if it can not allocate enough
memory, it returns NULL without first freeing the old packet.
This patch just frees the packet first.
Signed-off-by: Darren Jenkins <darrenrjenkins@gmail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If you do a modremove of any sas driver, you run into an oops on
shutdown when the host is removed (coming from the host bsg device).
The root cause seems to be that there's a use after free of the
bsg_class_device: In bsg_kref_release_function, this is used (to do a
put_device(bcg->parent) after bcg->release has been called. In sas (and
possibly many other things) bcd->release frees the queue which contains
the bsg_class_device, so we get a put_device on unreferenced memory.
Fix this by taking a copy of the pointer to the parent before releasing
bsg.
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
There's a fault on the FC controllers that makes them not respond
correctly to MSI. The SPI controllers are fine, but are likely to be
onboard on older motherboards which don't handle MSI correctly, so
default both these cases to disabled. Enable by setting the module
parameter mpt_msi_enable=1.
For the SAS case, enable MSI by default, but it can be disabled by
setting the module parameter mpt_msi_enable=0.
Cc: "Prakash, Sathya" <sathya.prakash@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Fix size of LDT entries. On x86-64, ldt_desc is a double-sized descriptor.
Signed-off-by: Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch corrects the handling of write operations to the IPMI watchdog
to work as intended by returning the number of characters actually
processed. Without this patch, an "echo V >/dev/watchdog" enables the
watchdog if IPMI is providing the watchdog function.
Signed-off-by: Mark Rustad <MRustad@gmail.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Currently, ipr does not support HDIO_GET_IDENTITY to SATA devices.
An oops occurs if userspace attempts to send the command. Since hald
issues the command, ensure we fail the ioctl in ipr. This is a
temporary solution to the oops. Once the ipr libata EH conversion
is upstream, ipr will fully support HDIO_GET_IDENTITY.
Tested-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
libata-acpi: don't call sleeping function from invalid context
Added Targa Visionary 1000 IDE adapter to pata_sis.c
libata-acpi: filter out DIPM enable
When we release the iclog, we do an atomic_dec_and_lock to determine if
we are the last reference and need to trigger update of log headers and
writeout. However, in xlog_state_get_iclog_space() we also need to
check if we have the last reference count there. If we do, we release
the log buffer, otherwise we decrement the reference count.
But the compare and decrement in xlog_state_get_iclog_space() is not
atomic, so both places can see a reference count of 2 and neither will
release the iclog. That leads to a filesystem hang.
Close the race by replacing the atomic_read() and atomic_dec() pair with
atomic_add_unless() to ensure that they are executed atomically.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Tim Shimmin <tes@sgi.com>
Tested-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The problem is introduced by commit
664d080c41.
acpi_evaluate_integer is a sleeping function,
and it should not be called with spin_lock_irqsave.
https://bugzilla.redhat.com/show_bug.cgi?id=451399
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Some BIOSen enable DIPM via _GTF which causes command timeouts under
certain configuration. This didn't occur on 2.6.25 because 2.6.25
defaulted to SRST, so _GTF wasn't executed during boot probe, so ahci
host reset disabled DIPM and as _GTF wasn't executed after SRST, DIPM
wasn't enabled. On 2.6.26, hardreset is used during probe and after
probe _GTF is executed enabling DIPM and thus the failures.
This patch could theoretically disable DIPM on machines which used to
have it enabled on 2.6.25 but AFAIK ahci is currently the only driver
which uses SATA ACPI hierarchy (_SDD) and as the host reset would have
always disabled DIPM, this shouldn't happen.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
The IRQ rate reported back by the RTC is incorrect when HPET is enabled.
Newer hardware that has HPET to emulate the legacy RTC device gets this value
wrong since after it sets the rate, it returns before setting the variable
used to report the IRQ rate back to users of the device -- so the set rate and
the reported rate get out of sync.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Brownell <david-b@pacbell.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (27 commits)
tun: Persistent devices can get stuck in xoff state
xfrm: Add a XFRM_STATE_AF_UNSPEC flag to xfrm_usersa_info
ipv6: missed namespace context in ipv6_rthdr_rcv
netlabel: netlink_unicast calls kfree_skb on error path by itself
ipv4: fib_trie: Fix lookup error return
tcp: correct kcalloc usage
ip: sysctl documentation cleanup
Documentation: clarify tcp_{r,w}mem sysctl docs
netfilter: nf_nat_snmp_basic: fix a range check in NAT for SNMP
netfilter: nf_conntrack_tcp: fix endless loop
libertas: fix memory alignment problems on the blackfin
zd1211rw: stop beacons on remove_interface
rt2x00: Disable synchronization during initialization
rc80211_pid: Fix fast_start parameter handling
sctp: Add documentation for sctp sysctl variable
ipv6: fix race between ipv6_del_addr and DAD timer
irda: Fix netlink error path return value
irda: New device ID for nsc-ircc
irda: via-ircc proper dma freeing
sctp: Mark the tsn as received after all allocations finish
...
The scenario goes like this. App stops reading from tun/tap.
TX queue gets full and driver does netif_stop_queue().
App closes fd and TX queue gets flushed as part of the cleanup.
Next time the app opens tun/tap and starts reading from it but
the xoff state is not cleared. We're stuck.
Normally xoff state is cleared when netdev is brought up. But
in the case of persistent devices this happens only during
initial setup.
The fix is trivial. If device is already up when an app opens
it we clear xoff state and that gets things moving again.
Signed-off-by: Max Krasnyansky <maxk@qualcomm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a XFRM_STATE_AF_UNSPEC flag to handle the AF_UNSPEC behavior for
the selector family. Userspace applications can set this flag to leave
the selector family of the xfrm_state unspecified. This can be used
to to handle inter family tunnels if the selector is not set from
userspace.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
So, no need to kfree_skb here on the error path. In this case we can
simply return.
Signed-off-by: Denis V. Lunev <den@openvz.org>
Acked-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In commit a07f5f508a "[IPV4] fib_trie: style
cleanup", the changes to check_leaf() and fn_trie_lookup() were wrong - where
fn_trie_lookup() would previously return a negative error value from
check_leaf(), it now returns 0.
Now fn_trie_lookup() doesn't appear to care about plen, so we can revert
check_leaf() to returning the error value.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Tested-by: William Boughton <bill@boughton.de>
Acked-by: Stephen Heminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
kcalloc is supposed to be called with the count as its first argument and
the element size as the second.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Reduced version of the spelling cleanup patch.
Take out the confusing language in tcp_frto, and organize the
undocumented values.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix some of the defaults and attempt to clarify some language.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Vegard Nossum reported a crash in kmem_cache_alloc():
BUG: unable to handle kernel paging request at da87d000
IP: [<c01991c7>] kmem_cache_alloc+0xc7/0xe0
*pde = 28180163 *pte = 1a87d160
Oops: 0002 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Pid: 3850, comm: grep Not tainted (2.6.26-rc9-00059-gb190333 #5)
EIP: 0060:[<c01991c7>] EFLAGS: 00210203 CPU: 0
EIP is at kmem_cache_alloc+0xc7/0xe0
EAX: 00000000 EBX: da87c100 ECX: 1adad71a EDX: 6b6b6b6b
ESI: 00200282 EDI: da87d000 EBP: f60bfe74 ESP: f60bfe54
DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
and analyzed it:
"The register %ecx looks innocent but is very important here. The disassembly:
mov %edx,%ecx
shr $0x2,%ecx
rep stos %eax,%es:(%edi) <-- the fault
So %ecx has been loaded from %edx... which is 0x6b6b6b6b/POISON_FREE.
(0x6b6b6b6b >> 2 == 0x1adadada.)
%ecx is the counter for the memset, from here:
memset(object, 0, c->objsize);
i.e. %ecx was loaded from c->objsize, so "c" must have been freed.
Where did "c" come from? Uh-oh...
c = get_cpu_slab(s, smp_processor_id());
This looks like it has very much to do with CPU hotplug/unplug. Is
there a race between SLUB/hotplug since the CPU slab is used after it
has been freed?"
Good analysis.
Yeah, it's possible that a caller of kmem_cache_alloc() -> slab_alloc()
can be migrated on another CPU right after local_irq_restore() and
before memset(). The inital cpu can become offline in the mean time (or
a migration is a consequence of the CPU going offline) so its
'kmem_cache_cpu' structure gets freed ( slab_cpuup_callback).
At some point of time the caller continues on another CPU having an
obsolete pointer...
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Reported-by: Vegard Nossum <vegard.nossum@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
