- 24 2月, 2012 1 次提交
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由 Pablo Neira Ayuso 提交于
This reverts commit af14cca1. This patch contains a race condition between packets and ctnetlink in the conntrack addition. A new patch to fix this issue follows up. Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
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- 23 2月, 2012 7 次提交
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由 Scott Talbert 提交于
In the current kernel implementation, the Logitech Harmony 900 remote control is matched to the cdc_ether driver through the generic USB_CDC_SUBCLASS_MDLM entry. However, this device appears to be of the pseudo-MDLM (Belcarra) type, rather than the standard one. This patch blacklists the Harmony 900 from the cdc_ether driver and whitelists it for the pseudo-MDLM driver in zaurus. Signed-off-by: NScott Talbert <talbert@techie.net> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Dan Carpenter 提交于
The intent was to clear out the icount struct here, but we accidentally clear stack memory instead. It probably will lead to a NULL dereference right away. Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 RongQing.Li 提交于
ip6_route_output() never returns NULL, so it is wrong to check if the return value is NULL. Signed-off-by: NRongQing.Li <roy.qing.li@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 RongQing.Li 提交于
ip6_route_output() never returns NULL, so it is wrong to check if the return value is NULL. Signed-off-by: NRongQing.Li <roy.qing.li@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 RongQing.Li 提交于
ip6_route_output() never returns NULL, so it is wrong to check if the return value is NULL. Signed-off-by: NRongQing.Li <roy.qing.li@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Guo-Fu Tseng 提交于
Set the RX FIFO flush watermark lower. According to Federico and JMicron's reply, setting it to 16QW would be stable on most platforms. Otherwise, user might experience packet drop issue. CC: stable@kernel.org Reported-by: NFederico Quagliata <federico@quagliata.org> Fixed-by: NFederico Quagliata <federico@quagliata.org> Signed-off-by: NGuo-Fu Tseng <cooldavid@cooldavid.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 22 2月, 2012 7 次提交
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由 Eric Dumazet 提交于
Commit 32092ecf (atm: clip: Use device neigh support on top of "arp_tbl".) introduced a bug since clip_tbl is zeroed : Crash occurs in __neigh_for_each_release() idle_timer_check() must use instead arp_tbl and neigh_check_cb() should ignore non clip neighbours. Idea from David Miller. Reported-by: NMeelis Roos <mroos@linux.ee> Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com> Tested-by: NMeelis Roos <mroos@linux.ee> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 David S. Miller 提交于
Don't return an uninitialized variable as the error, return -EOPNOTSUPP instead. Reported-by: NDave Jones <davej@redhat.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Greg Rose 提交于
Implement a new netlink attribute type IFLA_EXT_MASK. The mask is a 32 bit value that can be used to indicate to the kernel that certain extended ifinfo values are requested by the user application. At this time the only mask value defined is RTEXT_FILTER_VF to indicate that the user wants the ifinfo dump to send information about the VFs belonging to the interface. This patch fixes a bug in which certain applications do not have large enough buffers to accommodate the extra information returned by the kernel with large numbers of SR-IOV virtual functions. Those applications will not send the new netlink attribute with the interface info dump request netlink messages so they will not get unexpectedly large request buffers returned by the kernel. Modifies the rtnl_calcit function to traverse the list of net devices and compute the minimum buffer size that can hold the info dumps of all matching devices based upon the filter passed in via the new netlink attribute filter mask. If no filter mask is sent then the buffer allocation defaults to NLMSG_GOODSIZE. With this change it is possible to add yet to be defined netlink attributes to the dump request which should make it fairly extensible in the future. Signed-off-by: NGreg Rose <gregory.v.rose@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Michel Machado 提交于
When the fixed race condition happens: 1. While function neigh_periodic_work scans the neighbor hash table pointed by field tbl->nht, it unlocks and locks tbl->lock between buckets in order to call cond_resched. 2. Assume that function neigh_periodic_work calls cond_resched, that is, the lock tbl->lock is available, and function neigh_hash_grow runs. 3. Once function neigh_hash_grow finishes, and RCU calls neigh_hash_free_rcu, the original struct neigh_hash_table that function neigh_periodic_work was using doesn't exist anymore. 4. Once back at neigh_periodic_work, whenever the old struct neigh_hash_table is accessed, things can go badly. Signed-off-by: NMichel Machado <michel@digirati.com.br> Acked-by: NEric Dumazet <eric.dumazet@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Yevgeny Petrilin 提交于
In port type change flow, need to set the new port types only after all interfaces have finished the unregister process. Otherwise, during unregister, one of the interfaces might issue a SET_PORT command with wrong port types, it can cause bad FW behavior. Signed-off-by: NYevgeny Petrilin <yevgenyp@mellanox.co.il> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Yevgeny Petrilin 提交于
Under the spinlock we call request_irq(), which allocates memory with GFP_KERNEL, This causes the following trace when DEBUG_SPINLOCK is enabled, it can cause the following trace: BUG: spinlock wrong CPU on CPU#2, ethtool/2595 lock: ffff8801f9cbc2b0, .magic: dead4ead, .owner: ethtool/2595, .owner_cpu: 0 Pid: 2595, comm: ethtool Not tainted 3.0.18 #2 Call Trace: spin_bug+0xa2/0xf0 do_raw_spin_unlock+0x71/0xa0 _raw_spin_unlock+0xe/0x10 mlx4_assign_eq+0x12b/0x190 [mlx4_core] mlx4_en_activate_cq+0x252/0x2d0 [mlx4_en] ? mlx4_en_activate_rx_rings+0x227/0x370 [mlx4_en] mlx4_en_start_port+0x189/0xb90 [mlx4_en] mlx4_en_set_ringparam+0x29a/0x340 [mlx4_en] dev_ethtool+0x816/0xb10 ? dev_get_by_name_rcu+0xa4/0xe0 dev_ioctl+0x2b5/0x470 handle_mm_fault+0x1cd/0x2d0 sock_do_ioctl+0x5d/0x70 sock_ioctl+0x79/0x2f0 do_vfs_ioctl+0x8c/0x340 sys_ioctl+0xa1/0xb0 system_call_fastpath+0x16/0x1b Replacing with mutex, which is enough in this case. Signed-off-by: NYevgeny Petrilin <yevgenyp@mellanox.co.il> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Dave Jones 提交于
In 16adf5d0 I removed an over-broad alias that caused zaurus.ko to bind to unrelated devices. I had a report that at least one valid case no longer auto-loads because of this. This patch adds an ID for that case. Reported-by: NRaphael Wimmer <raphael.wimmer@ur.de> Signed-off-by: NDave Jones <davej@redhat.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 21 2月, 2012 5 次提交
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由 Jozsef Kadlecsik 提交于
Marcell Zambo and Janos Farago noticed and reported that when new conntrack entries are added via netlink and the conntrack table gets full, soft lockup happens. This is because the nf_conntrack_lock is held while nf_conntrack_alloc is called, which is in turn wants to lock nf_conntrack_lock while evicting entries from the full table. The patch fixes the soft lockup with limiting the holding of the nf_conntrack_lock to the minimum, where it's absolutely required. Signed-off-by: NJozsef Kadlecsik <kadlec@blackhole.kfki.hu> Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
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由 Joerg Willmann 提交于
ebt_among extension of ebtables uses __alignof__(_xt_align) while the corresponding kernel module uses __alignof__(ebt_replace) to determine the alignment in EBT_ALIGN(). These are the results of these values on different platforms: x86 x86_64 ppc __alignof__(_xt_align) 4 8 8 __alignof__(ebt_replace) 4 8 4 ebtables fails to add rules which use the among extension. I'm using kernel 2.6.33 and ebtables 2.0.10-4 According to Bart De Schuymer, userspace alignment was changed to _xt_align to fix an alignment issue on a userspace32-kernel64 system (he thinks it was for an ARM device). So userspace must be right. The kernel alignment macro needs to change so it also uses _xt_align instead of ebt_replace. The userspace changes date back from June 29, 2009. Signed-off-by: NJoerg Willmann <joe@clnt.de> Signed-off by: Bart De Schuymer <bdschuym@pandora.be> Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
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由 Jack Morgenstein 提交于
BF can be disabled in some cases, the capability field, bf_reg_size is set to zero in this case. Don't map the BF area in this case, it would cause failures. In addition, leaving the BF area unmapped also alerts the ETH driver to not use BF. Signed-off-by: NJack Morgenstein <jackm@dev.mellanox.co.il> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 John W. Linville 提交于
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless into for-davem
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- 20 2月, 2012 7 次提交
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由 Oliver Hartkopp 提交于
In the case of hotplug enabled devices (PCMCIA/PCIeC) the removal of the hardware can cause an infinite loop in the common sja1000 isr. Use the already retrieved status register to indicate a possible hardware removal and double check by reading the mode register in sja1000_is_absent. Cc: stable@kernel.org [3.2+] Signed-off-by: NOliver Hartkopp <socketcan@hartkopp.net> Acked-by: NWolfgang Grandegger <wg@grandegger.com> Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>
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由 Nikola Pajkovsky 提交于
WARNING: drivers/net/ethernet/broadcom/built-in.o(.init.text+0x5d): Section mismatch in reference from the function b44_init() to the function .exit.text:b44_pci_exit() module exits with b44_cleanup() Signed-off-by: NNikola Pajkovsky <n.pajkovsky@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Julia Lawall 提交于
The calls to pci_iounmap are in the wrong order, as compared to the associated calls to pci_iomap. A simplified version of the semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression e,x; statement S,S1; int ret; @@ e = pci_iomap(x,...) ... when != pci_iounmap(x,e) if (<+...e...+>) S ... when any when != pci_iounmap(x,e) *if (...) { ... when != pci_iounmap(x,e) return ...; } ... when any pci_iounmap(x,e); // </smpl> Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Dan Carpenter 提交于
netdev->irq is unsigned, so it's never less than zero. Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com> Tested-by: NJan Weitzel <j.weitzel@phytec.de> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Neil Horman 提交于
I was recently shown that vmxnet3 devices on transmit, will drop very small udp frames consistently. This is due to a regression introduced by commit 39d4a96f. This commit attempts to introduce an optimization to the tx path, indicating that the underlying hardware behaves optimally when at least 54 bytes of header data are available for direct access. This causes problems however, if the entire frame is less than 54 bytes long. The subsequent pskb_may_pull in vmxnet3_parse_and_copy_hdr fails, causing an error return code, which leads to vmxnet3_tq_xmit dropping the frame. Fix it by placing a cap on the copy length. For frames longer than 54 bytes, we do the pull as we normally would. If the frame is shorter than that, copy the whole frame, but no more. This ensures that we still get the optimization for qualifying frames, but don't do any damange for frames that are too short. Also, since I'm unable to do this, it wuold be great if vmware could follow up this patch with some additional code commentary as to why 54 bytes is an optimal pull length for a virtual NIC driver. The comment that introduced this was vague on that. Thanks! Signed-off-by: NNeil Horman <nhorman@tuxdriver.com> Reported-by: NMax Matveev <mmatveev@redhat.com> CC: Max Matveev <mmatveev@redhat.com> CC: "David S. Miller" <davem@davemloft.net> CC: Shreyas Bhatewara <sbhatewara@vmware.com> CC: "VMware, Inc." <pv-drivers@vmware.com> Signed-off-by: NShreyas N Bhatewara <sbhatewara@vmware.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Eric Dumazet 提交于
This driver attempts to use two TX rings but lacks proper support : 1) IRQ handler only takes care of TX completion on first TX ring 2) the stop/start logic uses the legacy functions (for non multiqueue drivers) This means all packets witk skb mark set to 1 are sent through high queue but are never cleaned and queue eventualy fills and block the device, triggering the infamous "NETDEV WATCHDOG" message. Lets use a single TX ring to fix the problem, this driver is not a real multiqueue one yet. Minimal fix for stable kernels. Reported-by: NThomas Meyer <thomas@m3y3r.de> Tested-by: NThomas Meyer <thomas@m3y3r.de> Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com> Cc: Jay Cliburn <jcliburn@gmail.com> Cc: Chris Snook <chris.snook@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Eric Dumazet 提交于
commit 50612537 (netem: fix classful handling) added two errors in netem_dequeue() 1) After checking skb at the head of tfifo queue for time constraints, it dequeues tail skb, thus adding unwanted reordering. 2) qdisc stats are updated twice per packet (one when packet dequeued from tfifo, once when delivered) Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 19 2月, 2012 12 次提交
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由 Linus Torvalds 提交于
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git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc由 Linus Torvalds 提交于
These are the bug fixes that have accumulated since 3.3-rc3 in arm-soc. The majority of them are regression fixes for stuff that broke during the merge 3.3 window. The notable ones are: * The at91 ata drivers both broke because of an earlier cleanup patch that some other patches were based on. Jean-Christophe decided to remove the legacy at91_ide driver and fix the new-style at91-pata driver while keeping the cleanup patch. I almost rejected the patches for being too late and too big but in the end decided to accept them because they fix a regression. * A patch fixing build breakage from the sysdev-to-device conversion colliding with other changes touches a number of mach-s3c files. * b0654037 "ARM: orion: Fix Orion5x GPIO regression from MPP cleanup" is a mechanical change that unfortunately touches a lot of lines that should up in the diffstat. * tag 'fixes-3.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (28 commits) ARM: at91: drop ide driver in favor of the pata one pata/at91: use newly introduced SMC accessors ARM: at91: add accessor to manage SMC ARM: at91:rtc/rtc-at91sam9: ioremap register bank ARM: at91: USB AT91 gadget registration for module ep93xx: fix build of vision_ep93xx.c ARM: OMAP2xxx: PM: fix OMAP2xxx-specific UART idle bug in v3.3 ARM: orion: Fix USB phy for orion5x. ARM: orion: Fix Orion5x GPIO regression from MPP cleanup ARM: EXYNOS: Add cpu-offset property in gic device tree node ARM: EXYNOS: Bring exynos4-dt up to date ARM: OMAP3: cm-t35: fix section mismatch warning ARM: OMAP2: Fix the OMAP2 only build break seen with 2011+ ARM tool-chains ARM: tegra: paz00: fix wrong UART port on mini-pcie plug ARM: tegra: paz00: fix wrong SD1 power gpio i2c: tegra: Add devexit_p() for remove ARM: EXYNOS: Correct M-5MOLS sensor clock frequency on Universal C210 board ARM: EXYNOS: Correct framebuffer window size on Nuri board ARM: SAMSUNG: Fix missing api-change from subsys_interface change ARM: EXYNOS: Fix "warning: initialization from incompatible pointer type" ...
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git://git.kernel.org/pub/scm/linux/kernel/git/davem/net由 Linus Torvalds 提交于
1) VETH_INFO_PEER netlink attribute needs to have it's size validated, from Thomas Graf. 2) 'poll' module option of bnx2x driver crashes the machine, just remove it. From Michal Schmidt. 3) ks8851_mll driver reads the irq number from two places, but only initializes one of them, oops. Use only one location and fix this problem, from Jan Weitzel. 4) Fix buffer overrun and unicast sterring bugs in mellanox mlx4 driver, from Eugenia Emantayev. 5) Swapped kcalloc() args in RxRPC and mlx4, from Axel Lin. 6) PHY MDIO device name regression fixes from Florian Fainelli. 7) If the wake event IRQ line is different from the netdevice one, we have to properly route it to the stmmac interrupt handler. From Francesco Virlinzi. 8) Fix rwlock lock initialization ordering bug in mac80211, from Mohammed Shafi Shajakhan. 9) TCP lost_cnt can get out of sync, and in fact go negative, in certain circumstances. Fix the way we specify what sequence range to operate on in tcp_sacktag_one() to fix this bug. From Neal Cardwell. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (27 commits) net/ethernet: ks8851_mll fix irq handling veth: Enforce minimum size of VETH_INFO_PEER stmmac: update the driver version to Feb 2012 (v2) stmmac: move hw init in the probe (v2) stmmac: request_irq when use an ext wake irq line (v2) stmmac: do not discard frame on dribbling bit assert ipheth: Add iPhone 4S mlx4: add unicast steering entries to resource_tracker mlx4: fix QP tree trashing mlx4: fix buffer overrun 3c59x: shorten timer period for slave devices netpoll: netpoll_poll_dev() should access dev->flags RxRPC: Fix kcalloc parameters swapped bnx2x: remove the 'poll' module option tcp: fix tcp_shifted_skb() adjustment of lost_cnt_hint for FACK ks8851: Fix NOHZ local_softirq_pending 08 warning bnx2x: fix bnx2x_storm_stats_update() on big endian ixp4xx-eth: fix PHY name to match MDIO bus name octeon: fix PHY name to match MDIO bus name fec: fix PHY name to match fixed MDIO bus name ...
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git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap由 Linus Torvalds 提交于
Fixes a bootstrapping issue for some registers when a less commonly used method for register cache initialisation is used. Only affects a fairly small proportion of users that both don't use explicit register defaults and do use the cache. * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap: regmap: Fix cache defaults initialization from raw cache defaults
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由 Linus Torvalds 提交于
Merge tag 'ecryptfs-3.3-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs Fixes maximum filename length and filesystem type reporting in statfs() calls and also fixes stale inode mode bits on eCryptfs inodes after a POSIX ACL was set on the lower filesystem's inode. * tag 'ecryptfs-3.3-rc4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs: ecryptfs: remove the second argument of k[un]map_atomic() eCryptfs: Copy up lower inode attrs after setting lower xattr eCryptfs: Improve statfs reporting
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git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl由 Linus Torvalds 提交于
pinctrl fixes for v3.3 * tag 'pinctrl-for-torvalds-20120216' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: pinctrl: restore pin naming
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git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc由 Linus Torvalds 提交于
Here are a few more fixes for powerpc. Some are regressions, the rest is simple/obvious/nasty enough that I deemed it good to go now. Here's also step one of deprecating legacy iSeries support: we are removing it from the main defconfig. Nobody seems to be using it anymore and the code is nasty to maintain, (involves horrible hacks in various low level areas of the kernel) so we plan to actually rip it out at some point. For now let's just avoid building it by default. Stephen will proceed to do the actual removal later (probably 3.4 or 3.5). * 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: powerpc/perf: power_pmu_start restores incorrect values, breaking frequency events powerpc/adb: Use set_current_state() powerpc: Disable interrupts early in Program Check powerpc: Remove legacy iSeries from ppc64_defconfig powerpc/fsl/pci: Fix PCIe fixup regression powerpc: Fix kernel log of oops/panic instruction dump
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git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci由 Linus Torvalds 提交于
One regression fix for SR-IOV on PPC and a couple of misc fixes from Yinghai. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci: PCI: Fix pci cardbus removal PCI: set pci sriov page size before reading SRIOV BAR PCI: workaround hard-wired bus number V2
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git://people.freedesktop.org/~airlied/linux由 Linus Torvalds 提交于
3 radeon fixes, I have some exynos fixes to push later but I'll queue them separately once I've looked them over a bit. * 'drm-fixes' of git://people.freedesktop.org/~airlied/linux: drm/radeon/kms: fix MSI re-arm on rv370+ drm/radeon/kms/atom: bios scratch reg handling updates drm/radeon/kms: drop lock in return path of radeon_fence_count_emitted.
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git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6由 Linus Torvalds 提交于
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: crypto: sha512 - use standard ror64()
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由 Linus Torvalds 提交于
After all the FPU state cleanups and finally finding the problem that caused all our FPU save/restore problems, this re-introduces the preloading of FPU state that was removed in commit b3b0870e ("i387: do not preload FPU state at task switch time"). However, instead of simply reverting the removal, this reimplements preloading with several fixes, most notably - properly abstracted as a true FPU state switch, rather than as open-coded save and restore with various hacks. In particular, implementing it as a proper FPU state switch allows us to optimize the CR0.TS flag accesses: there is no reason to set the TS bit only to then almost immediately clear it again. CR0 accesses are quite slow and expensive, don't flip the bit back and forth for no good reason. - Make sure that the same model works for both x86-32 and x86-64, so that there are no gratuitous differences between the two due to the way they save and restore segment state differently due to architectural differences that really don't matter to the FPU state. - Avoid exposing the "preload" state to the context switch routines, and in particular allow the concept of lazy state restore: if nothing else has used the FPU in the meantime, and the process is still on the same CPU, we can avoid restoring state from memory entirely, just re-expose the state that is still in the FPU unit. That optimized lazy restore isn't actually implemented here, but the infrastructure is set up for it. Of course, older CPU's that use 'fnsave' to save the state cannot take advantage of this, since the state saving also trashes the state. In other words, there is now an actual _design_ to the FPU state saving, rather than just random historical baggage. Hopefully it's easier to follow as a result. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
This moves the bit that indicates whether a thread has ownership of the FPU from the TS_USEDFPU bit in thread_info->status to a word of its own (called 'has_fpu') in task_struct->thread.has_fpu. This fixes two independent bugs at the same time: - changing 'thread_info->status' from the scheduler causes nasty problems for the other users of that variable, since it is defined to be thread-synchronous (that's what the "TS_" part of the naming was supposed to indicate). So perfectly valid code could (and did) do ti->status |= TS_RESTORE_SIGMASK; and the compiler was free to do that as separate load, or and store instructions. Which can cause problems with preemption, since a task switch could happen in between, and change the TS_USEDFPU bit. The change to TS_USEDFPU would be overwritten by the final store. In practice, this seldom happened, though, because the 'status' field was seldom used more than once, so gcc would generally tend to generate code that used a read-modify-write instruction and thus happened to avoid this problem - RMW instructions are naturally low fat and preemption-safe. - On x86-32, the current_thread_info() pointer would, during interrupts and softirqs, point to a *copy* of the real thread_info, because x86-32 uses %esp to calculate the thread_info address, and thus the separate irq (and softirq) stacks would cause these kinds of odd thread_info copy aliases. This is normally not a problem, since interrupts aren't supposed to look at thread information anyway (what thread is running at interrupt time really isn't very well-defined), but it confused the heck out of irq_fpu_usable() and the code that tried to squirrel away the FPU state. (It also caused untold confusion for us poor kernel developers). It also turns out that using 'task_struct' is actually much more natural for most of the call sites that care about the FPU state, since they tend to work with the task struct for other reasons anyway (ie scheduling). And the FPU data that we are going to save/restore is found there too. Thanks to Arjan Van De Ven <arjan@linux.intel.com> for pointing us to the %esp issue. Cc: Arjan van de Ven <arjan@linux.intel.com> Reported-and-tested-by: NRaphael Prevost <raphael@buro.asia> Acked-and-tested-by: NSuresh Siddha <suresh.b.siddha@intel.com> Tested-by: NPeter Anvin <hpa@zytor.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 17 2月, 2012 1 次提交
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由 Linus Torvalds 提交于
The AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception is pending. In order to not leak FIP state from one process to another, we need to do a floating point load after the fxsave of the old process, and before the fxrstor of the new FPU state. That resets the state to the (uninteresting) kernel load, rather than some potentially sensitive user information. We used to do this directly after the FPU state save, but that is actually very inconvenient, since it (a) corrupts what is potentially perfectly good FPU state that we might want to lazy avoid restoring later and (b) on x86-64 it resulted in a very annoying ordering constraint, where "__unlazy_fpu()" in the task switch needs to be delayed until after the DS segment has been reloaded just to get the new DS value. Coupling it to the fxrstor instead of the fxsave automatically avoids both of these issues, and also ensures that we only do it when actually necessary (the FP state after a save may never actually get used). It's simply a much more natural place for the leaked state cleanup. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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