linux/kernel, branch v3.7

Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2012-12-06T16:29:08Z

Pull module signing fixes from Rusty Russell: "David gave me these a month ago, during my git workflow churn :(" * 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: ASN.1: Fix an indefinite length skip error MODSIGN: Don't use enum-type bitfields in module signature info block

Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2012-12-06T16:27:11Z

Pull watchdog fix from Thomas Gleixner: "Trivial CPU hotplug regression fix for the watchdog code" * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: watchdog: Fix CPU hotplug regression

MODSIGN: Don't use enum-type bitfields in module signature info block

2012-12-05T00:57:24Z

Don't use enum-type bitfields in the module signature info block as we can't be certain how the compiler will handle them. As I understand it, it is arch dependent, and it is possible for the compiler to rearrange them based on endianness and to insert a byte of padding to pad the three enums out to four bytes. Instead use u8 fields for these, which the compiler should emit in the right order without padding. Signed-off-by: David Howells Signed-off-by: Rusty Russell

watchdog: Fix CPU hotplug regression

2012-12-04T18:56:59Z

Norbert reported: "3.7-rc6 booted with nmi_watchdog=0 fails to suspend to RAM or offline CPUs. It's reproducable with a KVM guest and physical system." The reason is that commit bcd951cf(watchdog: Use hotplug thread infrastructure) missed to take this into account. So the cpu offline code gets stuck in the teardown function because it accesses non initialized data structures. Add a check for watchdog_enabled into that path to cure the issue. Reported-and-tested-by: Norbert Warmuth Tested-by: Joseph Salisbury Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1211231033230.2701@ionos Link: http://bugs.launchpad.net/bugs/1079534 Signed-off-by: Thomas Gleixner

Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2012-12-04T17:32:12Z

Pull module fixes from Rusty Russell: "Module signing build fixes for blackfin and metag" * 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: modsign: add symbol prefix to certificate list linux/kernel.h: define SYMBOL_PREFIX

Merge branch 'for-3.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

2012-12-04T17:02:45Z

Pull workqueue fixes from Tejun Heo: "So, safe fixes my ass. Commit 8852aac25e79 ("workqueue: mod_delayed_work_on() shouldn't queue timer on 0 delay") had the side-effect of performing delayed_work sanity checks even when @delay is 0, which should be fine for any sane use cases. Unfortunately, megaraid was being overly ingenious. It seemingly wanted to use cancel_delayed_work_sync() before cancel_work_sync() was introduced, but didn't want to waste the space for full delayed_work as it was only going to use 0 @delay. So, it only allocated space for struct work_struct and then cast it to struct delayed_work and passed it into delayed_work functions - truly awesome engineering tradeoff to save some bytes. Xiaotian fixed it by making megraid allocate full delayed_work for now. It should be converted to use work_struct and cancel_work_sync() but I think we better do that after 3.7. I added another commit to change BUG_ON()s in __queue_delayed_work() to WARN_ON_ONCE()s so that the kernel doesn't crash even if there are more such abuses." * 'for-3.7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: convert BUG_ON()s in __queue_delayed_work() to WARN_ON_ONCE()s megaraid: fix BUG_ON() from incorrect use of delayed work

workqueue: convert BUG_ON()s in __queue_delayed_work() to WARN_ON_ONCE()s

2012-12-04T15:58:47Z

8852aac25e ("workqueue: mod_delayed_work_on() shouldn't queue timer on 0 delay") unexpectedly uncovered a very nasty abuse of delayed_work in megaraid - it allocated work_struct, casted it to delayed_work and then pass that into queue_delayed_work(). Previously, this was okay because 0 @delay short-circuited to queue_work() before doing anything with delayed_work. 8852aac25e moved 0 @delay test into __queue_delayed_work() after sanity check on delayed_work making megaraid trigger BUG_ON(). Although megaraid is already fixed by c1d390d8e6 ("megaraid: fix BUG_ON() from incorrect use of delayed work"), this patch converts BUG_ON()s in __queue_delayed_work() to WARN_ON_ONCE()s so that such abusers, if there are more, trigger warning but don't crash the machine. Signed-off-by: Tejun Heo Cc: Xiaotian Feng

Revert "sched, autogroup: Stop going ahead if autogroup is disabled"

2012-12-03T19:10:24Z

This reverts commit 800d4d30c8f20bd728e5741a3b77c4859a613f7c. Between commits 8323f26ce342 ("sched: Fix race in task_group()") and 800d4d30c8f2 ("sched, autogroup: Stop going ahead if autogroup is disabled"), autogroup is a wreck. With both applied, all you have to do to crash a box is disable autogroup during boot up, then reboot.. boom, NULL pointer dereference due to commit 800d4d30c8f2 not allowing autogroup to move things, and commit 8323f26ce342 making that the only way to switch runqueues: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] effective_load.isra.43+0x50/0x90 Pid: 7047, comm: systemd-user-se Not tainted 3.6.8-smp #7 MEDIONPC MS-7502/MS-7502 RIP: effective_load.isra.43+0x50/0x90 Process systemd-user-se (pid: 7047, threadinfo ffff880221dde000, task ffff88022618b3a0) Call Trace: select_task_rq_fair+0x255/0x780 try_to_wake_up+0x156/0x2c0 wake_up_state+0xb/0x10 signal_wake_up+0x28/0x40 complete_signal+0x1d6/0x250 __send_signal+0x170/0x310 send_signal+0x40/0x80 do_send_sig_info+0x47/0x90 group_send_sig_info+0x4a/0x70 kill_pid_info+0x3a/0x60 sys_kill+0x97/0x1a0 ? vfs_read+0x120/0x160 ? sys_read+0x45/0x90 system_call_fastpath+0x16/0x1b Code: 49 0f af 41 50 31 d2 49 f7 f0 48 83 f8 01 48 0f 46 c6 48 2b 07 48 8b bf 40 01 00 00 48 85 ff 74 3a 45 31 c0 48 8b 8f 50 01 00 00 <48> 8b 11 4c 8b 89 80 00 00 00 49 89 d2 48 01 d0 45 8b 59 58 4c RIP [] effective_load.isra.43+0x50/0x90 RSP CR2: 0000000000000000 Signed-off-by: Mike Galbraith Acked-by: Ingo Molnar Cc: Yong Zhang Cc: Peter Zijlstra Cc: stable@vger.kernel.org # 2.6.39+ Signed-off-by: Linus Torvalds

modsign: add symbol prefix to certificate list

2012-12-03T02:36:25Z

Add the arch symbol prefix (if applicable) to the asm definition of modsign_certificate_list and modsign_certificate_list_end. This uses the recently defined SYMBOL_PREFIX which is derived from CONFIG_SYMBOL_PREFIX. This fixes the build of module signing on the blackfin and metag architectures. Signed-off-by: James Hogan Cc: Rusty Russell Cc: David Howells Cc: Mike Frysinger Signed-off-by: Rusty Russell

workqueue: mod_delayed_work_on() shouldn't queue timer on 0 delay

2012-12-02T00:43:18Z

8376fe22c7 ("workqueue: implement mod_delayed_work[_on]()") implemented mod_delayed_work[_on]() using the improved try_to_grab_pending(). The function is later used, among others, to replace [__]candel_delayed_work() + queue_delayed_work() combinations. Unfortunately, a delayed_work item w/ zero @delay is handled slightly differently by mod_delayed_work_on() compared to queue_delayed_work_on(). The latter skips timer altogether and directly queues it using queue_work_on() while the former schedules timer which will expire on the closest tick. This means, when @delay is zero, that [__]cancel_delayed_work() + queue_delayed_work_on() makes the target item immediately executable while mod_delayed_work_on() may induce delay of upto a full tick. This somewhat subtle difference breaks some of the converted users. e.g. block queue plugging uses delayed_work for deferred processing and uses mod_delayed_work_on() when the queue needs to be immediately unplugged. The above problem manifested as noticeably higher number of context switches under certain circumstances. The difference in behavior was caused by missing special case handling for 0 delay in mod_delayed_work_on() compared to queue_delayed_work_on(). Joonsoo Kim posted a patch to add it - ("workqueue: optimize mod_delayed_work_on() when @delay == 0")[1]. The patch was queued for 3.8 but it was described as optimization and I missed that it was a correctness issue. As both queue_delayed_work_on() and mod_delayed_work_on() use __queue_delayed_work() for queueing, it seems that the better approach is to move the 0 delay special handling to the function instead of duplicating it in mod_delayed_work_on(). Fix the problem by moving 0 delay special case handling from queue_delayed_work_on() to __queue_delayed_work(). This replaces Joonsoo's patch. [1] http://thread.gmane.org/gmane.linux.kernel/1379011/focus=1379012 Signed-off-by: Tejun Heo Reported-and-tested-by: Anders Kaseorg Reported-and-tested-by: Zlatko Calusic LKML-Reference: LKML-Reference: <50A78AA9.5040904@iskon.hr> Cc: Joonsoo Kim