Reset restart_block.fn on executing a sigreturn such that any currently
pending system call restarts will be forced to return -EINTR.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 4969c1192d ("mm: fix swapin race condition") is now agreed to
be incomplete. There's a race, not very much less likely than the
original race envisaged, in which it is further necessary to check that
the swapcache page's swap has not changed.
Here's the reasoning: cast in terms of reuse_swap_page(), but probably
could be reformulated to rely on try_to_free_swap() instead, or on
swapoff+swapon.
A, faults into do_swap_page(): does page1 = lookup_swap_cache(swap1) and
comes through the lock_page(page1).
B, a racing thread of the same process, faults on the same address: does
page1 = lookup_swap_cache(swap1) and now waits in lock_page(page1), but
for whatever reason is unlucky not to get the lock any time soon.
A carries on through do_swap_page(), a write fault, but cannot reuse the
swap page1 (another reference to swap1). Unlocks the page1 (but B
doesn't get it yet), does COW in do_wp_page(), page2 now in that pte.
C, perhaps the parent of A+B, comes in and write faults the same swap
page1 into its mm, reuse_swap_page() succeeds this time, swap1 is freed.
kswapd comes in after some time (B still unlucky) and swaps out some
pages from A+B and C: it allocates the original swap1 to page2 in A+B,
and some other swap2 to the original page1 now in C. But does not
immediately free page1 (actually it couldn't: B holds a reference),
leaving it in swap cache for now.
B at last gets the lock on page1, hooray! Is PageSwapCache(page1)? Yes.
Is pte_same(*page_table, orig_pte)? Yes, because page2 has now been
given the swap1 which page1 used to have. So B proceeds to insert page1
into A+B's page_table, though its content now belongs to C, quite
different from what A wrote there.
B ought to have checked that page1's swap was still swap1.
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mattst88/alpha-2.6:
alpha: deal with multiple simultaneously pending signals
alpha: fix a 14 years old bug in sigreturn tracing
alpha: unb0rk sigsuspend() and rt_sigsuspend()
alpha: belated ERESTART_RESTARTBLOCK race fix
alpha: Shift perf event pending work earlier in timer interrupt
alpha: wire up fanotify and prlimit64 syscalls
alpha: kill big kernel lock
alpha: fix build breakage in asm/cacheflush.h
alpha: remove unnecessary cast from void* in assignment.
alpha: Use static const char * const where possible
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (21 commits)
dca: disable dca on IOAT ver.3.0 multiple-IOH platforms
netpoll: Disable IRQ around RCU dereference in netpoll_rx
sctp: Do not reset the packet during sctp_packet_config().
net/llc: storing negative error codes in unsigned short
MAINTAINERS: move atlx discussions to netdev
drivers/net/cxgb3/cxgb3_main.c: prevent reading uninitialized stack memory
drivers/net/eql.c: prevent reading uninitialized stack memory
drivers/net/usb/hso.c: prevent reading uninitialized memory
xfrm: dont assume rcu_read_lock in xfrm_output_one()
r8169: Handle rxfifo errors on 8168 chips
3c59x: Remove atomic context inside vortex_{set|get}_wol
tcp: Prevent overzealous packetization by SWS logic.
net: RPS needs to depend upon USE_GENERIC_SMP_HELPERS
phylib: fix PAL state machine restart on resume
net: use rcu_barrier() in rollback_registered_many
bonding: correctly process non-linear skbs
ipv4: enable getsockopt() for IP_NODEFRAG
ipv4: force_igmp_version ignored when a IGMPv3 query received
ppp: potential NULL dereference in ppp_mp_explode()
net/llc: make opt unsigned in llc_ui_setsockopt()
...
Coda's REQ_* defines were renamed to avoid clashes with the block layer
(commit 4aeefdc69f7b: "coda: fixup clash with block layer REQ_*
defines").
However one was missed and response messages are no longer matched with
requests and waiting threads are no longer woken up. This patch fixes
this.
Signed-off-by: Jan Harkes <jaharkes@cs.cmu.edu>
[ Also fixed up whitespace while at it -Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Unlike the other targets, alpha sets _one_ sigframe and
buggers off until the next syscall/interrupt, even if
more signals are pending. It leads to quite a few unpleasant
inconsistencies, starting with SIGSEGV potentially arriving
not where it should and including e.g. mess with sigsuspend();
consider two pending signals blocked until sigsuspend()
unblocks them. We pick the first one; then, if we are hit
by interrupt while in the handler, we process the second one
as well. If we are not, and if no syscalls had been made,
we get out of the first handler and leave the second signal
pending; normally sigreturn() would've picked it anyway, but
here it starts with restoring the original mask and voila -
the second signal is blocked again. On everything else we
get both delivered consistently.
It's actually easy to fix; the only thing to watch out for
is prevention of double syscall restart. Fortunately, the
idea I've nicked from arm fix by rmk works just fine...
Testcase demonstrating the behaviour in question; on alpha
we get one or both flags set (usually one), on everything
else both are always set.
#include <signal.h>
#include <stdio.h>
int had1, had2;
void f1(int sig) { had1 = 1; }
void f2(int sig) { had2 = 1; }
main()
{
sigset_t set1, set2;
sigemptyset(&set1);
sigemptyset(&set2);
sigaddset(&set2, 1);
sigaddset(&set2, 2);
signal(1, f1);
signal(2, f2);
sigprocmask(SIG_SETMASK, &set2, NULL);
raise(1);
raise(2);
sigsuspend(&set1);
printf("had1:%d had2:%d\n", had1, had2);
}
Tested-by: Michael Cree <mcree@orcon.net.nz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matt Turner <mattst88@gmail.com>
The way sigreturn() is implemented on alpha breaks PTRACE_SYSCALL,
all way back to 1.3.95 when alpha has grown PTRACE_SYSCALL support.
What happens is direct return to ret_from_syscall, in order to bypass
mangling of a3 (error indicator) and prevent other mutilations of
registers (e.g. by syscall restart). That's fine, but... the entire
TIF_SYSCALL_TRACE codepath is kept separate on alpha and post-syscall
stopping/notifying the tracer is after the syscall. And the normal
path we are forcibly switching to doesn't have it.
So we end up with *one* stop in traced sigreturn() vs. two in other
syscalls. And yes, strace is visibly broken by that; try to strace
the following
#include <signal.h>
#include <stdio.h>
void f(int sig) {}
main()
{
signal(SIGHUP, f);
raise(SIGHUP);
write(1, "eeeek\n", 6);
}
and watch the show. The
close(1) = 405
in the end of strace output is coming from return value of write() (6 ==
__NR_close on alpha) and syscall number of exit_group() (__NR_exit_group ==
405 there).
The fix is fairly simple - the only thing we end up missing is the call
of syscall_trace() and we can tell whether we'd been called from the
SYSCALL_TRACE path by checking ra value. Since we are setting the
switch_stack up (that's what sys_sigreturn() does), we have the right
environment for calling syscall_trace() - just before we call
undo_switch_stack() and return. Since undo_switch_stack() will overwrite
s0 anyway, we can use it to store the result of "has it been called from
SYSCALL_TRACE path?" check. The same thing applies in rt_sigreturn().
Tested-by: Michael Cree <mcree@orcon.net.nz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matt Turner <mattst88@gmail.com>
Old code used to set regs->r0 and regs->r19 to force the right
return value. Leaving that after switch to ERESTARTNOHAND
was a Bad Idea(tm), since now that screws the restart - if we
hit the case when get_signal_to_deliver() returns 0, we will
step back to syscall insn, with v0 set to EINTR and a3 to 1.
The latter won't matter, since EINTR is 4, aka __NR_write.
Testcase:
#include <signal.h>
#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>
main()
{
sigset_t mask;
sigemptyset(&mask);
sigaddset(&mask, SIGCONT);
sigprocmask(SIG_SETMASK, &mask, NULL);
kill(0, SIGCONT);
syscall(__NR_sigsuspend, 1, "b0rken\n", 7);
}
results on alpha in immediate message to stdout...
Fix is obvious; moreover, since we don't need regs anymore, we can
switch to normal prototypes for these guys and lose the wrappers.
Even better, rt_sigsuspend() is identical to generic version in
kernel/signal.c now.
Tested-by: Michael Cree <mcree@orcon.net.nz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matt Turner <mattst88@gmail.com>
same thing as had been done on other targets back in 2003 -
move setting ->restart_block.fn into {rt_,}sigreturn().
Tested-by: Michael Cree <mcree@orcon.net.nz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Matt Turner <mattst88@gmail.com>
Pending work from the performance event subsystem is executed in
the timer interrupt. This patch shifts the call to
perf_event_do_pending() before the call to update_process_times()
as the latter may call back into the perf event subsystem and it
is prudent to have the pending work executed first.
Signed-off-by: Michael Cree <mcree@orcon.net.nz>
Signed-off-by: Matt Turner <mattst88@gmail.com>
The 2.6.36-rc kernel added three new system calls:
fanotify_init, fanotify_mark, and prlimit64. This
patch wires them up on Alpha.
Built and booted on an XP900. Untested beyond that.
Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Matt Turner <mattst88@gmail.com>
All uses of the BKL on alpha are totally bogus, nothing
is really protected by this. Remove the remaining users
so we don't have to mark alpha as 'depends on BKL'.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: linux-alpha@vger.kernel.org
Signed-off-by: Matt Turner <mattst88@gmail.com>
Alpha SMP flush_icache_user_range() is implemented as an inline
function inside include/asm/cacheflush.h. It dereferences @current
but doesn't include linux/sched.h and thus causes build failure if
linux/sched.h wasn't included previously. Fix it by including the
needed header file explicitly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Matt Turner <mattst88@gmail.com>
Direct Cache Access is not supported on IOAT ver.3.0 multiple-IOH platforms.
This patch blocks registering of dca providers when multiple IOH detected with IOAT ver.3.0.
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add IORESOURCE_IRQ_HIGHLEVEL irq flag to dm9000 driver
platform data in board mach-real6410.
Signed-off-by: Darius Augulis <augulis.darius@gmail.com>
[kgene.kim@samsung.com: minor title fix]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Fix errors reported by checkpatch.pl script
Signed-off-by: Darius Augulis <augulis.darius@gmail.com>
[kgene.kim@samsung.com: minor title fix]
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Avoids build warnings due to the undeclared non-statics.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
We cannot use rcu_dereference_bh safely in netpoll_rx as we may
be called with IRQs disabled. We could however simply disable
IRQs as that too causes BH to be disabled and is safe in either
case.
Thanks to John Linville for discovering this bug and providing
a patch.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
sctp_packet_config() is called when getting the packet ready
for appending of chunks. The function should not touch the
current state, since it's possible to ping-pong between two
transports when sending, and that can result packet corruption
followed by skb overlfow crash.
Reported-by: Thomas Dreibholz <dreibh@iem.uni-due.de>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
hwmon: (lm95241) Replace rate sysfs attribute with update_interval
hwmon: (adm1031) Replace update_rate sysfs attribute with update_interval
hwmon: (w83627ehf) Use proper exit sequence
hwmon: (emc1403) Remove unnecessary hwmon_device_unregister
hwmon: (f75375s) Do not overwrite values read from registers
hwmon: (f75375s) Shift control mode to the correct bit position
hwmon: New subsystem maintainers
hwmon: (lis3lv02d) Prevent NULL pointer dereference
* 'for-linus' of git://neil.brown.name/md:
md: fix v1.x metadata update when a disk is missing.
md: call md_update_sb even for 'external' metadata arrays.
If a signal hits us outside of a syscall and another gets delivered
when we are in sigreturn (e.g. because it had been in sa_mask for
the first one and got sent to us while we'd been in the first handler),
we have a chance of returning from the second handler to location one
insn prior to where we ought to return. If r0 happens to contain -513
(-ERESTARTNOINTR), sigreturn will get confused into doing restart
syscall song and dance.
Incredible joy to debug, since it manifests as random, infrequent and
very hard to reproduce double execution of instructions in userland
code...
The fix is simple - mark it "don't bother with restarts" in wrapper,
i.e. set r8 to 0 in sys_sigreturn and sys_rt_sigreturn wrappers,
suppressing the syscall restart handling on return from these guys.
They can't legitimately return a restart-worthy error anyway.
Testcase:
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/time.h>
#include <errno.h>
void f(int n)
{
__asm__ __volatile__(
"ldr r0, [%0]\n"
"b 1f\n"
"b 2f\n"
"1:b .\n"
"2:\n" : : "r"(&n));
}
void handler1(int sig) { }
void handler2(int sig) { raise(1); }
void handler3(int sig) { exit(0); }
main()
{
struct sigaction s = {.sa_handler = handler2};
struct itimerval t1 = { .it_value = {1} };
struct itimerval t2 = { .it_value = {2} };
signal(1, handler1);
sigemptyset(&s.sa_mask);
sigaddset(&s.sa_mask, 1);
sigaction(SIGALRM, &s, NULL);
signal(SIGVTALRM, handler3);
setitimer(ITIMER_REAL, &t1, NULL);
setitimer(ITIMER_VIRTUAL, &t2, NULL);
f(-513); /* -ERESTARTNOINTR */
write(1, "buggered\n", 9);
return 1;
}
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
update_interval is the matching attribute defined in the hwmon sysfs ABI.
Use it.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The attribute reflects an interval, not a rate.
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Ira W. Snyder <iws@ovro.caltech.edu>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
According to the datasheet for Winbond W83627DHG the proper way to exit
the Extended Function Mode is to write 0xaa to the EFER(0x2e or 0x4e).
Signed-off-by: Jonas Jonsson <jonas@ludd.ltu.se>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
It is unnecessary and wrong to call hwmon_device_unregister in error
handling before hwmon_device_register is called.
Signed-off-by: Yong Wang <yong.y.wang@intel.com>
Reviewed-by: Guenter Roeck <guenter.roeck@ericsson.com>
Cc: stable@kernel.org
Signed-off-by: Jean Delvare <khali@linux-fr.org>
All bits in the values read from registers to be used for the next
write were getting overwritten, avoid doing so to not mess with the
current configuration.
Signed-off-by: Guillem Jover <guillem@hadrons.org>
Cc: Riku Voipio <riku.voipio@iki.fi>
Cc: stable@kernel.org
Signed-off-by: Jean Delvare <khali@linux-fr.org>
The spec notes that fan0 and fan1 control mode bits are located in bits
7-6 and 5-4 respectively, but the FAN_CTRL_MODE macro was making the
bits shift by 5 instead of by 4.
Signed-off-by: Guillem Jover <guillem@hadrons.org>
Cc: Riku Voipio <riku.voipio@iki.fi>
Cc: stable@kernel.org
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Guenter Roeck volunteered to adopt the hwmon subsystem as long as he
wasn't the only maintainer. As this was also my own condition, we can
add the two of us as co-maintainers of the hwmon subsystem.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>
If CONFIG_PM was selected and lis3lv02d_platform_data was NULL,
the kernel will be panic when halt command run.
Reported-by: Yusuke Goda <yusuke.goda.sx@renesas.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Samu Onkalo <samu.p.onkalo@nokia.com>
Sigend-off-by: Jean Delvare <khali@linux-fr.org>
Looks like this crept in, in a recent update.
Reported-by: Krzysztof Urbaniak <urban@bash.org.pl>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
If the alloc_skb() fails then we return 65431 instead of -ENOBUFS
(-105).
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The atlx drivers are sufficiently mature that we no longer need a separate
mailing list for them. Move the discussion to netdev, so we can decommission
atl1-devel, which is now mostly spam.
Signed-off-by: Chris Snook <chris.snook@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixed formatting (tabs and line breaks).
The CHELSIO_GET_QSET_NUM device ioctl allows unprivileged users to read
4 bytes of uninitialized stack memory, because the "addr" member of the
ch_reg struct declared on the stack in cxgb_extension_ioctl() is not
altered or zeroed before being copied back to the user. This patch
takes care of it.
Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixed formatting (tabs and line breaks).
The EQL_GETMASTRCFG device ioctl allows unprivileged users to read 16
bytes of uninitialized stack memory, because the "master_name" member of
the master_config_t struct declared on the stack in eql_g_master_cfg()
is not altered or zeroed before being copied back to the user. This
patch takes care of it.
Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fixed formatting (tabs and line breaks).
The TIOCGICOUNT device ioctl allows unprivileged users to read
uninitialized stack memory, because the "reserved" member of the
serial_icounter_struct struct declared on the stack in hso_get_count()
is not altered or zeroed before being copied back to the user. This
patch takes care of it.
Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_local_out() is called with rcu_read_lock() held from ip_queue_xmit()
but not from other call sites.
Reported-and-bisected-by: Nick Bowler <nbowler@elliptictech.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If an array with 1.x metadata is assembled with the last disk missing,
md doesn't properly record the fact that the disk was missing.
This is unlikely to cause a real problem as the event count will be
different to the count on the missing disk so it won't be included in
the array. However it could still cause confusion.
So make sure we clear all the relevant slots, not just the early ones.
Signed-off-by: NeilBrown <neilb@suse.de>
Now that we depend on md_update_sb to clear variable bits in
mddev->flags (rather than trying not to set them) it is important to
always call md_update_sb when appropriate.
md_check_recovery has this job but explicitly avoids it for ->external
metadata arrays. This is not longer appropraite, or needed.
However we do want to avoid taking the mddev lock if only
MD_CHANGE_PENDING is set as that is not cleared by md_update_sb for
external-metadata arrays.
Reported-by: "Kwolek, Adam" <adam.kwolek@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: hpet: Work around hardware stupidity
x86, build: Disable -fPIE when compiling with CONFIG_CC_STACKPROTECTOR=y
x86, cpufeature: Suppress compiler warning with gcc 3.x
x86, UV: Fix initialization of max_pnode
drivers/firewire/nosy* is a stand-alone driver that does not depend on
CONFIG_FIREWIRE. Hence let make descend into drivers/firewire/ also
if that option is off.
The stand-alone driver drivers/ieee1394/init_ohci1394_dma* will soon be
moved into drivers/firewire/ too and will require the same makefile fix.
Side effect:
As mentioned in https://bugzilla.novell.com/show_bug.cgi?id=586172#c24
this influences the order in which either firewire-ohci or ohci1394 is
going to be bound to an OHCI-1394 controller in case of a modular build
of both drivers if no modprobe blacklist entries are configured.
However, a user of such a setup cannot expect deterministic behavior
anyway. The Kconfig help and the migration guide at
ieee1394.wiki.kernel.org recommend blacklist entries when a dual
IEEE 1394 stack build is being used. (The coexistence period of the two
stacks is planned to end soon.)
Cc: Michal Marek <mmarek@suse.cz>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
The PCM proc files may open a race against substream close, which can
end up with an Oops. Use the open_mutex to protect for it.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Al Viro