- 18 Oct, 2013 40 commits
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Davidlohr Bueso authored
commit 68eccc1d upstream. Similar to semctl and msgctl, when calling msgctl, the *_INFO and *_STAT commands can be performed without acquiring the ipc object. Add a shmctl_nolock() function and move the logic of *_INFO and *_STAT out of msgctl(). Since we are just moving functionality, this change still takes the lock and it will be properly lockless in the next patch. Signed-off-by:
Davidlohr Bueso <davidlohr.bueso@hp.com> Tested-by:
Sedat Dilek <sedat.dilek@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Davidlohr Bueso authored
commit 3b1c4ad3 upstream. Now that sem, msgque and shm, through *_down(), all use the lockless variant of ipcctl_pre_down(), go ahead and delete it. [akpm@linux-foundation.org: fix function name in kerneldoc, cleanups] Signed-off-by:
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Davidlohr Bueso authored
commit 79ccf0f8 upstream. Instead of holding the ipc lock for the entire function, use the ipcctl_pre_down_nolock and only acquire the lock for specific commands: RMID and SET. Signed-off-by:
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Davidlohr Bueso authored
commit 8b8d52ac upstream. This is the third and final patchset that deals with reducing the amount of contention we impose on the ipc lock (kern_ipc_perm.lock). These changes mostly deal with shared memory, previous work has already been done for semaphores and message queues: http://lkml.org/lkml/2013/3/20/546 (sems) http://lkml.org/lkml/2013/5/15/584 (mqueues) With these patches applied, a custom shm microbenchmark stressing shmctl doing IPC_STAT with 4 threads a million times, reduces the execution time by 50%. A similar run, this time with IPC_SET, reduces the execution time from 3 mins and 35 secs to 27 seconds. Patches 1-8: replaces blindly taking the ipc lock for a smarter combination of rcu and ipc_obtain_object, only acquiring the spinlock when updating. Patch 9: renames the ids rw_mutex to rwsem, which is what it already was. Patch 10: is a trivial mqueue leftover cleanup Patch 11: adds a brief lock scheme description, requested by Andrew. This patch: Add shm_obtain_object() and shm_obtain_object_check(), which will allow us to get the ipc object without acquiring the lock. Just as with other forms of ipc, these functions are basically wrappers around ipc_obtain_object*(). Signed-off-by:
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Manfred Spraul authored
commit bebcb928 upstream. The check if the queue is full and adding current to the wait queue of pending msgsnd() operations (ss_add()) must be atomic. Otherwise: - the thread that performs msgsnd() finds a full queue and decides to sleep. - the thread that performs msgrcv() first reads all messages from the queue and then sleeps, because the queue is empty. - the msgrcv() calls do not perform any wakeups, because the msgsnd() task has not yet called ss_add(). - then the msgsnd()-thread first calls ss_add() and then sleeps. Net result: msgsnd() and msgrcv() both sleep forever. Observed with msgctl08 from ltp with a preemptible kernel. Fix: Call ipc_lock_object() before performing the check. The patch also moves security_msg_queue_msgsnd() under ipc_lock_object: - msgctl(IPC_SET) explicitely mentions that it tries to expunge any pending operations that are not allowed anymore with the new permissions. If security_msg_queue_msgsnd() is called without locks, then there might be races. - it makes the patch much simpler. Reported-and-tested-by:
Vineet Gupta <Vineet.Gupta1@synopsys.com> Acked-by:
Rik van Riel <riel@redhat.com> Signed-off-by:
Manfred Spraul <manfred@colorfullife.com> Signed-off-by:
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Manfred Spraul authored
commit 758a6ba3 upstream. Cleanup: Some minor points that I noticed while writing the previous patches 1) The name try_atomic_semop() is misleading: The function performs the operation (if it is possible). 2) Some documentation updates. No real code change, a rename and documentation changes. Signed-off-by:
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Manfred Spraul authored
commit d12e1e50 upstream. sem_otime contains the time of the last semaphore operation that completed successfully. Every operation updates this value, thus access from multiple cpus can cause thrashing. Therefore the patch replaces the variable with a per-semaphore variable. The per-array sem_otime is only calculated when required. No performance improvement on a single-socket i3 - only important for larger systems. Signed-off-by:
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Manfred Spraul authored
commit f269f40a upstream. There are two places that can contain alter operations: - the global queue: sma->pending_alter - the per-semaphore queues: sma->sem_base[].pending_alter. Since one of the queues must be processed first, this causes an odd priorization of the wakeups: complex operations have priority over simple ops. The patch restores the behavior of linux <=3.0.9: The longest waiting operation has the highest priority. This is done by using only one queue: - if there are complex ops, then sma->pending_alter is used. - otherwise, the per-semaphore queues are used. As a side effect, do_smart_update_queue() becomes much simpler: no more goto logic. Signed-off-by:
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Manfred Spraul authored
commit 1a82e9e1 upstream. Introduce separate queues for operations that do not modify the semaphore values. Advantages: - Simpler logic in check_restart(). - Faster update_queue(): Right now, all wait-for-zero operations are always tested, even if the semaphore value is not 0. - wait-for-zero gets again priority, as in linux <=3.0.9 Signed-off-by:
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Manfred Spraul authored
commit f5c936c0 upstream. As now each semaphore has its own spinlock and parallel operations are possible, give each semaphore its own cacheline. On a i3 laptop, this gives up to 28% better performance: #semscale 10 | grep "interleave 2" - before: Cpus 1, interleave 2 delay 0: 36109234 in 10 secs Cpus 2, interleave 2 delay 0: 55276317 in 10 secs Cpus 3, interleave 2 delay 0: 62411025 in 10 secs Cpus 4, interleave 2 delay 0: 81963928 in 10 secs -after: Cpus 1, interleave 2 delay 0: 35527306 in 10 secs Cpus 2, interleave 2 delay 0: 70922909 in 10 secs <<< + 28% Cpus 3, interleave 2 delay 0: 80518538 in 10 secs Cpus 4, interleave 2 delay 0: 89115148 in 10 secs <<< + 8.7% i3, with 2 cores and with hyperthreading enabled. Interleave 2 in order use first the full cores. HT partially hides the delay from cacheline trashing, thus the improvement is "only" 8.7% if 4 threads are running. Signed-off-by:
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Manfred Spraul authored
commit 196aa013 upstream. Enforce that ipc_rcu_alloc returns a cacheline aligned pointer on SMP. Rationale: The SysV sem code tries to move the main spinlock into a seperate cacheline (____cacheline_aligned_in_smp). This works only if ipc_rcu_alloc returns cacheline aligned pointers. vmalloc and kmalloc return cacheline algined pointers, the implementation of ipc_rcu_alloc breaks that. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
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Davidlohr Bueso authored
commit 9ad66ae6 upstream. We can now drop the msg_lock and msg_lock_check functions along with a bogus comment introduced previously in semctl_down. Signed-off-by:
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Davidlohr Bueso authored
commit 41a0d523 upstream. do_msgrcv() is the last msg queue function that abuses the ipc lock Take it only when needed when actually updating msq. Signed-off-by:
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Davidlohr Bueso authored
commit 3dd1f784 upstream. do_msgsnd() is another function that does too many things with the ipc object lock acquired. Take it only when needed when actually updating msq. Signed-off-by:
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Davidlohr Bueso authored
commit ac0ba20e upstream. While the INFO cmd doesn't take the ipc lock, the STAT commands do acquire it unnecessarily. We can do the permissions and security checks only holding the rcu lock. This function now mimics semctl_nolock(). Signed-off-by:
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Davidlohr Bueso authored
commit a5001a0d upstream. Add msq_obtain_object() and msq_obtain_object_check(), which will allow us to get the ipc object without acquiring the lock. Just as with semaphores, these functions are basically wrappers around ipc_obtain_object*(). Signed-off-by:
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Davidlohr Bueso authored
commit 2cafed30 upstream. Similar to semctl, when calling msgctl, the *_INFO and *_STAT commands can be performed without acquiring the ipc object. Add a msgctl_nolock() function and move the logic of *_INFO and *_STAT out of msgctl(). This change still takes the lock and it will be properly lockless in the next patch Signed-off-by:
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Davidlohr Bueso authored
commit 15724ecb upstream. Instead of holding the ipc lock for the entire function, use the ipcctl_pre_down_nolock and only acquire the lock for specific commands: RMID and SET. Signed-off-by:
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Davidlohr Bueso authored
commit 7b4cc5d8 upstream. This function currently acquires both the rw_mutex and the rcu lock on successful lookups, leaving the callers to explicitly unlock them, creating another two level locking situation. Make the callers (including those that still use ipcctl_pre_down()) explicitly lock and unlock the rwsem and rcu lock. Signed-off-by:
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Davidlohr Bueso authored
commit cf9d5d78 upstream. Signed-off-by:
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Davidlohr Bueso authored
commit 1ca7003a upstream. Simple helpers around the (kern_ipc_perm *)->lock spinlock. Signed-off-by:
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Davidlohr Bueso authored
commit dbfcd91f upstream. This patchset continues the work that began in the sysv ipc semaphore scaling series, see https://lkml.org/lkml/2013/3/20/546 Just like semaphores used to be, sysv shared memory and msg queues also abuse the ipc lock, unnecessarily holding it for operations such as permission and security checks. This patchset mostly deals with mqueues, and while shared mem can be done in a very similar way, I want to get these patches out in the open first. It also does some pending cleanups, mostly focused on the two level locking we have in ipc code, taking care of ipc_addid() and ipcctl_pre_down_nolock() - yes there are still functions that need to be updated as well. This patch: Make all callers explicitly take and release the RCU read lock. This addresses the two level locking seen in newary(), newseg() and newqueue(). For the last two, explicitly unlock the ipc object and the rcu lock, instead of calling the custom shm_unlock and msg_unlock functions. The next patch will deal with the open coded locking for ->perm.lock Signed-off-by:
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wojciech kapuscinski authored
commit 50b8f5ae upstream. They have 4 rather than 8. Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=63599Signed-off-by:
wojciech kapuscinski <wojtask9@wp.pl> Signed-off-by:
Alex Deucher <alexander.deucher@amd.com> Signed-off-by:
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Alex Deucher authored
commit aa3e146d upstream. Wrong bit offset for SRC endian swapping. Signed-off-by:
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Dan Carpenter authored
commit 89cd67b3 upstream. The error path does this: for (--i; i >= 0; --i) { which is a forever loop because "i" is unsigned. Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
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Chris Wilson authored
commit c9976dcf upstream. The current test for an attached enabled encoder fails if we have multiple connectors aliased to the same encoder - both connectors believe they own the enabled encoder and so we attempt to both enable and disable DPMS on the encoder, leading to hilarity and an OOPs: [ 354.803064] WARNING: CPU: 0 PID: 482 at /usr/src/linux/dist/3.11.2/drivers/gpu/drm/i915/intel_display.c:3869 intel_modeset_check_state+0x764/0x770 [i915]() [ 354.803064] wrong connector dpms state [ 354.803084] Modules linked in: nfsd auth_rpcgss oid_registry exportfs nfs lockd sunrpc xt_nat iptable_nat nf_nat_ipv4 nf_nat xt_limit xt_LOG xt_tcpudp nf_conntrack_ipv4 nf_defrag_ipv4 ipt_REJECT ipv6 xt_recent xt_conntrack nf_conntrack iptable_filter ip_tables x_tables snd_hda_codec_realtek snd_hda_codec_hdmi x86_pkg_temp_thermal snd_hda_intel coretemp kvm_intel snd_hda_codec i915 kvm snd_hwdep snd_pcm_oss snd_mixer_oss crc32_pclmul snd_pcm crc32c_intel e1000e intel_agp igb ghash_clmulni_intel intel_gtt aesni_intel cfbfillrect aes_x86_64 cfbimgblt lrw cfbcopyarea drm_kms_helper ptp video thermal processor gf128mul snd_page_alloc drm snd_timer glue_helper 8250_pci snd pps_core ablk_helper agpgart cryptd sg soundcore fan i2c_algo_bit sr_mod thermal_sys 8250 i2c_i801 serial_core hwmon cdrom i2c_core evdev button [ 354.803086] CPU: 0 PID: 482 Comm: kworker/0:1 Not tainted 3.11.2 #1 [ 354.803087] Hardware name: Supermicro X10SAE/X10SAE, BIOS 1.00 05/03/2013 [ 354.803091] Workqueue: events console_callback [ 354.803092] 0000000000000009 ffff88023611db48 ffffffff814048ac ffff88023611db90 [ 354.803093] ffff88023611db80 ffffffff8103d4e3 ffff880230d82800 ffff880230f9b800 [ 354.803094] ffff880230f99000 ffff880230f99448 ffff8802351c0e00 ffff88023611dbe0 [ 354.803094] Call Trace: [ 354.803098] [<ffffffff814048ac>] dump_stack+0x54/0x8d [ 354.803101] [<ffffffff8103d4e3>] warn_slowpath_common+0x73/0x90 [ 354.803103] [<ffffffff8103d547>] warn_slowpath_fmt+0x47/0x50 [ 354.803109] [<ffffffffa089f1be>] ? intel_ddi_connector_get_hw_state+0x5e/0x110 [i915] [ 354.803114] [<ffffffffa0896974>] intel_modeset_check_state+0x764/0x770 [i915] [ 354.803117] [<ffffffffa08969bb>] intel_connector_dpms+0x3b/0x60 [i915] [ 354.803120] [<ffffffffa037e1d0>] drm_fb_helper_dpms.isra.11+0x120/0x160 [drm_kms_helper] [ 354.803122] [<ffffffffa037e24e>] drm_fb_helper_blank+0x3e/0x80 [drm_kms_helper] [ 354.803123] [<ffffffff812116c2>] fb_blank+0x52/0xc0 [ 354.803125] [<ffffffff8121e04b>] fbcon_blank+0x21b/0x2d0 [ 354.803127] [<ffffffff81062243>] ? update_rq_clock.part.74+0x13/0x30 [ 354.803129] [<ffffffff81047486>] ? lock_timer_base.isra.30+0x26/0x50 [ 354.803130] [<ffffffff810472b2>] ? internal_add_timer+0x12/0x40 [ 354.803131] [<ffffffff81047f48>] ? mod_timer+0xf8/0x1c0 [ 354.803133] [<ffffffff81266d61>] do_unblank_screen+0xa1/0x1c0 [ 354.803134] [<ffffffff81268087>] poke_blanked_console+0xc7/0xd0 [ 354.803136] [<ffffffff812681cf>] console_callback+0x13f/0x160 [ 354.803137] [<ffffffff81053258>] process_one_work+0x148/0x3d0 [ 354.803138] [<ffffffff81053f19>] worker_thread+0x119/0x3a0 [ 354.803140] [<ffffffff81053e00>] ? manage_workers.isra.30+0x2a0/0x2a0 [ 354.803141] [<ffffffff8105994b>] kthread+0xbb/0xc0 [ 354.803142] [<ffffffff81059890>] ? kthread_create_on_node+0x120/0x120 [ 354.803144] [<ffffffff8140b32c>] ret_from_fork+0x7c/0xb0 [ 354.803145] [<ffffffff81059890>] ? kthread_create_on_node+0x120/0x120 This regression goes back to the big modeset rework and the conversion to the new dpms helpers which started with: commit 5ab432ef Author: Daniel Vetter <daniel.vetter@ffwll.ch> Date: Sat Jun 30 08:59:56 2012 +0200 drm/i915/hdmi: convert to encoder->disable/enable Fixes: igt/kms_flip/dpms-off-confusion Reported-and-tested-by:
Wakko Warner <wakko@animx.eu.org> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68030 Link: http://lkml.kernel.org/r/20130928185023.GA21672@animx.eu.orgSigned-off-by:
Chris Wilson <chris@chris-wilson.co.uk> [danvet: Add regression citation, mention the igt testcase this fixes and slap a cc: stable on the patch.] Signed-off-by:
Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by:
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Al Viro authored
commit 118b2302 upstream. dynamic_dname() is both too much and too little for those - the output may be well in excess of 64 bytes dynamic_dname() assumes to be enough (thanks to ashmem feeding really long names to shmem_file_setup()) and vsnprintf() is an overkill for those guys. Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk> Cc: Colin Cross <ccross@google.com> Signed-off-by:
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David Henningsson authored
This is a backport for stable. The original commit SHA is 338cae56. On this machine, DAC on node 0x03 seems to give mono output. Also, it needs additional patches for headset mic support. It supports CTIA style headsets only. Alsa-info available at the bug link below. BugLink: https://bugs.launchpad.net/bugs/1236228Signed-off-by:
David Henningsson <david.henningsson@canonical.com> Signed-off-by:
Takashi Iwai <tiwai@suse.de> Signed-off-by:
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Ingo Molnar authored
commit 3f0116c3 upstream. Fengguang Wu, Oleg Nesterov and Peter Zijlstra tracked down a kernel crash to a GCC bug: GCC miscompiles certain 'asm goto' constructs, as outlined here: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670 Implement a workaround suggested by Jakub Jelinek. Reported-and-tested-by:
Fengguang Wu <fengguang.wu@intel.com> Reported-by:
Oleg Nesterov <oleg@redhat.com> Reported-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Suggested-by:
Jakub Jelinek <jakub@redhat.com> Reviewed-by:
Richard Henderson <rth@twiddle.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20131015062351.GA4666@gmail.comSigned-off-by:
Ingo Molnar <mingo@kernel.org> Signed-off-by:
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Dan Carpenter authored
commit 8612ed0d upstream. Calling the WDIOC_GETSTATUS & WDIOC_GETBOOTSTATUS and twice will cause a interruptible deadlock. Signed-off-by:
Guenter Roeck <linux@roeck-us.net> Signed-off-by:
Wim Van Sebroeck <wim@iguana.be> Cc: Jonghwan Choi <jhbird.choi@samsung.com> Signed-off-by:
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Vineet Gupta authored
commit 5b242828 upstream. ARCompact TRAP_S insn used for breakpoints, commits before exception is taken (updating architectural PC). So ptregs->ret contains next-PC and not the breakpoint PC itself. This is different from other restartable exceptions such as TLB Miss where ptregs->ret has exact faulting PC. gdb needs to know exact-PC hence ARC ptrace GETREGSET provides for @stop_pc which returns ptregs->ret vs. EFA depending on the situation. However, writing stop_pc (SETREGSET request), which updates ptregs->ret doesn't makes sense stop_pc doesn't always correspond to that reg as described above. This was not an issue so far since user_regs->ret / user_regs->stop_pc had same value and both writing to ptregs->ret was OK, needless, but NOT broken, hence not observed. With gdb "jump", they diverge, and user_regs->ret updating ptregs is overwritten immediately with stop_pc, which this patch fixes. Reported-by:
Anton Kolesov <akolesov@synopsys.com> Signed-off-by:
Vineet Gupta <vgupta@synopsys.com> Signed-off-by:
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Christian Ruppert authored
commit 10469350 upstream. Previously, when a signal was registered with SA_SIGINFO, parameters 2 and 3 of the signal handler were written to registers r1 and r2 before the register set was saved. This led to corruption of these two registers after returning from the signal handler (the wrong values were restored). With this patch, registers are now saved before any parameters are passed, thus maintaining the processor state from before signal entry. Signed-off-by:
Christian Ruppert <christian.ruppert@abilis.com> Signed-off-by:
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Vineet Gupta authored
commit 6c00350b upstream. Some ARC SMP systems lack native atomic R-M-W (LLOCK/SCOND) insns and can only use atomic EX insn (reg with mem) to build higher level R-M-W primitives. This includes a SystemC based SMP simulation model. So rwlocks need to use a protecting spinlock for atomic cmp-n-exchange operation to update reader(s)/writer count. The spinlock operation itself looks as follows: mov reg, 1 ; 1=locked, 0=unlocked retry: EX reg, [lock] ; load existing, store 1, atomically BREQ reg, 1, rety ; if already locked, retry In single-threaded simulation, SystemC alternates between the 2 cores with "N" insn each based scheduling. Additionally for insn with global side effect, such as EX writing to shared mem, a core switch is enforced too. Given that, 2 cores doing a repeated EX on same location, Linux often got into a livelock e.g. when both cores were fiddling with tasklist lock (gdbserver / hackbench) for read/write respectively as the sequence diagram below shows: core1 core2 -------- -------- 1. spin lock [EX r=0, w=1] - LOCKED 2. rwlock(Read) - LOCKED 3. spin unlock [ST 0] - UNLOCKED spin lock [EX r=0,w=1] - LOCKED -- resched core 1---- 5. spin lock [EX r=1] - ALREADY-LOCKED -- resched core 2---- 6. rwlock(Write) - READER-LOCKED 7. spin unlock [ST 0] 8. rwlock failed, retry again 9. spin lock [EX r=0, w=1] -- resched core 1---- 10 spinlock locked in #9, retry #5 11. spin lock [EX gets 1] -- resched core 2---- ... ... The fix was to unlock using the EX insn too (step 7), to trigger another SystemC scheduling pass which would let core1 proceed, eliding the livelock. Signed-off-by:
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Vineet Gupta authored
commit 0752adfd upstream. Anton reported | LTP tests syscalls/process_vm_readv01 and process_vm_writev01 fail | similarly in one testcase test_iov_invalid -> lvec->iov_base. | Testcase expects errno EFAULT and return code -1, | but it gets return code 1 and ERRNO is 0 what means success. Essentially test case was passing a pointer of -1 which access_ok() was not catching. It was doing [@addr + @sz <= TASK_SIZE] which would pass for @addr == -1 Fixed that by rewriting as [@addr <= TASK_SIZE - @sz] Reported-by:
Anton Kolesov <Anton.Kolesov@synopsys.com> Signed-off-by:
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Mischa Jonker authored
commit c11eb222 upstream. If a load or store is the last instruction in a zero-overhead-loop, and it's misaligned, the loop would execute only once. This fixes that problem. Signed-off-by:
Mischa Jonker <mjonker@synopsys.com> Signed-off-by:
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Mischa Jonker authored
commit 7efd0da2 upstream. Cast usecs to u64, to ensure that the (usecs * 4295 * HZ) multiplication is 64 bit. Initially, the (usecs * 4295 * HZ) part was done as a 32 bit multiplication, with the result casted to 64 bit. This led to some bits falling off, causing a "DMA initialization error" in the stmmac Ethernet driver, due to a premature timeout. Signed-off-by:
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Noam Camus authored
commit c3567f8a upstream. Commit 05b016ec "ARC: Setup Vector Table Base in early boot" moved the Interrupt vector Table setup out of arc_init_IRQ() which is called for all CPUs, to entry point of boot cpu only, breaking booting of others. Fix by adding the same to entry point of non-boot CPUs too. read_arc_build_cfg_regs() printing IVT Base Register didn't help the casue since it prints a synthetic value if zero which is totally bogus, so fix that to print the exact Register. [vgupta: Remove the now stale comment from header of arc_init_IRQ and also added the commentary for halt-on-reset] Cc: Gilad Ben-Yossef <gilad@benyossef.com> Signed-off-by:
Noam Camus <noamc@ezchip.com> Signed-off-by:
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Vineet Gupta authored
commit 05b016ec upstream. Otherwise early boot exceptions such as instructions errors due to configuration mismatch between kernel and hardware go off to la-la land, as opposed to hitting the handler and panic()'ing properly. Signed-off-by:
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Russell King authored
commit 1d0bbf42 upstream. Signed-off-by:
Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by:
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Helge Deller authored
commit 59b33f14 upstream. Running an "echo t > /proc/sysrq-trigger" crashes the parisc kernel. The problem is, that in print_worker_info() we try to read the workqueue info via the probe_kernel_read() functions which use pagefault_disable() to avoid crashes like this: probe_kernel_read(&pwq, &worker->current_pwq, sizeof(pwq)); probe_kernel_read(&wq, &pwq->wq, sizeof(wq)); probe_kernel_read(name, wq->name, sizeof(name) - 1); The problem here is, that the first probe_kernel_read(&pwq) might return zero in pwq and as such the following probe_kernel_reads() try to access contents of the page zero which is read protected and generate a kernel segfault. With this patch we fix the interruption handler to call parisc_terminate() directly only if pagefault_disable() was not called (in which case preempt_count()==0). Otherwise we hand over to the pagefault handler which will try to look up the faulting address in the fixup tables. Signed-off-by:
Helge Deller <deller@gmx.de> Signed-off-by:
John David Anglin <dave.anglin@bell.net> Signed-off-by:
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