- 10 Apr, 2017 22 commits
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Jan Kara authored
When userspace task processing fanotify permission events screws up and does not respond, fsnotify_mark_srcu SRCU is held indefinitely which causes further hangs in the whole notification subsystem. Although we cannot easily solve the problem of operations blocked waiting for response from userspace, we can at least somewhat localize the damage by dropping SRCU lock before waiting for userspace response and reacquiring it when userspace responds. Reviewed-by:
Miklos Szeredi <mszeredi@redhat.com> Reviewed-by:
Amir Goldstein <amir73il@gmail.com> Signed-off-by:
Jan Kara <jack@suse.cz>
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Jan Kara authored
Pass fsnotify_iter_info into ->handle_event() handler so that it can release and reacquire SRCU lock via fsnotify_prepare_user_wait() and fsnotify_finish_user_wait() functions. These functions also make sure current marks are appropriately pinned so that iteration protected by srcu in fsnotify() stays safe. Reviewed-by:
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Jan Kara authored
fanotify wants to drop fsnotify_mark_srcu lock when waiting for response from userspace so that the whole notification subsystem is not blocked during that time. This patch provides a framework for safely getting mark reference for a mark found in the object list which pins the mark in that list. We can then drop fsnotify_mark_srcu, wait for userspace response and then safely continue iteration of the object list once we reaquire fsnotify_mark_srcu. Reviewed-by:
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Jan Kara authored
Currently we queue all marks for destruction on group shutdown and then destroy them from fsnotify_destroy_group() instead from a worker thread which is the usual path. However worker can already be processing some list of marks to destroy so this does not make 100% all marks are really destroyed by the time group is shut down. This isn't a big problem as each mark holds group reference and thus group stays partially alive until all marks are really freed but there's no point in complicating our lives - just wait for the delayed work to be finished instead. Reviewed-by:
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Jan Kara authored
Instead of removing mark from object list from fsnotify_detach_mark(), remove the mark when last reference to the mark is dropped. This will allow fanotify to wait for userspace response to event without having to hold onto fsnotify_mark_srcu. To avoid pinning inodes by elevated refcount (and thus e.g. delaying file deletion) while someone holds mark reference, we detach connector from the object also from fsnotify_destroy_marks() and not only after removing last mark from the list as it was now. Reviewed-by:
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Jan Kara authored
Currently we queue mark into a list of marks for destruction in __fsnotify_free_mark() and keep the last mark reference dangling. After the worker waits for SRCU period, it drops the last reference to the mark which frees it. This scheme has the disadvantage that if we hold reference to a mark and drop and reacquire SRCU lock, the mark can get freed immediately which is slightly inconvenient and we will need to avoid this in the future. Move to a scheme where queueing of mark into a list of marks for destruction happens when the last reference to the mark is dropped. Also drop reference to the mark held by group list already when mark is removed from that list instead of dropping it only from the destruction worker. Reviewed-by:
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Jan Kara authored
Dropping mark reference can result in mark being freed. Although it should not happen in inotify_remove_from_idr() since caller should hold another reference, just don't risk lock up just after WARN_ON unnecessarily. Also fold do_inotify_remove_from_idr() into the single callsite as that function really is just two lines of real code. Reviewed-by:
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Jan Kara authored
Currently we free fsnotify_mark_connector structure only when inode / vfsmount is getting freed. This can however impose noticeable memory overhead when marks get attached to inodes only temporarily. So free the connector structure once the last mark is detached from the object. Since notification infrastructure can be working with the connector under the protection of fsnotify_mark_srcu, we have to be careful and free the fsnotify_mark_connector only after SRCU period passes. Reviewed-by:
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Jan Kara authored
So far list of marks attached to an object (inode / vfsmount) was protected by i_lock or mnt_root->d_lock. This dictates that the list must be empty before the object can be destroyed although the list is now anchored in the fsnotify_mark_connector structure. Protect the list by a spinlock in the fsnotify_mark_connector structure to decouple lifetime of a list of marks from a lifetime of the object. This also simplifies the code quite a bit since we don't have to differentiate between inode and vfsmount lists in quite a few places anymore. Reviewed-by:
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Jan Kara authored
After removing all the indirection it is clear that hlist_del_init_rcu(&mark->obj_list); in fsnotify_destroy_marks() is not needed as the mark gets removed from the list shortly afterwards in fsnotify_destroy_mark() -> fsnotify_detach_mark() -> fsnotify_detach_from_object(). Also there is no problem with mark being visible on object list while we call fsnotify_destroy_mark() as parallel destruction of marks from several places is properly handled (as mentioned in the comment in fsnotify_destroy_marks(). So just remove the list removal and also the stale comment. Reviewed-by:
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Jan Kara authored
We lock object list lock in fsnotify_detach_from_object() twice - once to detach mark and second time to recalculate mask. That is unnecessary and later it will become problematic as we will free the connector as soon as there is no mark in it. So move recalculation of fsnotify mask into the same critical section that is detaching mark. This also removes recalculation of child dentry flags from fsnotify_detach_from_object(). That is however fine. Those marks will get recalculated once some event happens on a child. Reviewed-by:
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Jan Kara authored
fsnotify_detach_mark() calls fsnotify_destroy_inode_mark() or fsnotify_destroy_vfsmount_mark() to remove mark from object list. These two functions are however very similar and differ only in the lock they use to protect the object list of marks. Simplify the code by removing the indirection and removing mark from the object list in a common function. Reviewed-by:
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Jan Kara authored
Instead of passing spinlock into fsnotify_destroy_marks() determine it directly in that function from the connector type. This will reduce code churn when changing lock protecting list of marks. Reviewed-by:
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Jan Kara authored
Move locking of a mark list into fsnotify_find_mark(). This reduces code churn in the following patch changing lock protecting the list. Reviewed-by:
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Jan Kara authored
Move locking of locks protecting a list of marks into fsnotify_recalc_mask(). This reduces code churn in the following patch which changes the lock protecting the list of marks. Reviewed-by:
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Jan Kara authored
Move fsnotify_destroy_marks() to be later in the fs/notify/mark.c. It will need some functions that are declared after its current declaration. No functional change. Reviewed-by:
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Jan Kara authored
Adding notification mark to object list has been currently done through fsnotify_add_{inode|vfsmount}_mark() helpers from fsnotify_add_mark_locked() which call fsnotify_add_mark_list(). Remove this unnecessary indirection to simplify the code. Pushing all the locking to fsnotify_add_mark_list() also allows us to allocate the connector structure with GFP_KERNEL mode. Reviewed-by: -
Jan Kara authored
Currently inode reference is held by fsnotify marks. Change the rules so that inode reference is held by fsnotify_mark_connector structure whenever the list is non-empty. This simplifies the code and is more logical. Reviewed-by:
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Jan Kara authored
Move pointer to inode / vfsmount from mark itself to the fsnotify_mark_connector structure. This is another step on the path towards decoupling inode / vfsmount lifetime from notification mark lifetime. Reviewed-by:
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Jan Kara authored
Currently notification marks are attached to object (inode or vfsmnt) by a hlist_head in the object. The list is also protected by a spinlock in the object. So while there is any mark attached to the list of marks, the object must be pinned in memory (and thus e.g. last iput() deleting inode cannot happen). Also for list iteration in fsnotify() to work, we must hold fsnotify_mark_srcu lock so that mark itself and mark->obj_list.next cannot get freed. Thus we are required to wait for response to fanotify events from userspace process with fsnotify_mark_srcu lock held. That causes issues when userspace process is buggy and does not reply to some event - basically the whole notification subsystem gets eventually stuck. So to be able to drop fsnotify_mark_srcu lock while waiting for response, we have to pin the mark in memory and make sure it stays in the object list (as removing the mark waiting for response could lead to lost notification events for groups later in the list). However we don't want inode reclaim to block on such mark as that would lead to system just locking up elsewhere. This commit is the first in the series that paves way towards solving these conflicting lifetime needs. Instead of anchoring the list of marks directly in the object, we anchor it in a dedicated structure (fsnotify_mark_connector) and just point to that structure from the object. The following commits will also add spinlock protecting the list and object pointer to the structure. Reviewed-by:
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Jan Kara authored
Add a comment that lifetime of a notification mark is protected by SRCU and remove a comment about clearing of marks attached to the inode. It is stale and more uptodate version is at fsnotify_destroy_marks() which is the function handling this case. Reviewed-by:
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Jan Kara authored
Currently audit code uses checking of mark->inode to verify whether mark is still alive. Switch that to checking mark flags as that is more logical and current way will become unreliable in future. Reviewed-by:
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- 05 Apr, 2017 1 commit
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Jan Kara authored
Audit tree currently uses inode pointer as a key into the hash table. Getting that from notification mark will be somewhat more difficult with coming fsnotify changes. So abstract getting of hash key from the audit chunk and inode so that we can change the method to obtain a key easily. Reviewed-by:
Paul Moore <paul@paul-moore.com> Signed-off-by:
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- 03 Apr, 2017 3 commits
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Jan Kara authored
Move recalculation of inode / vfsmount notification mask under group->mark_mutex of the mark which was modified. These are the only places where mask recalculation happens without mark being protected from detaching from inode / vfsmount which will cause issues with the following patches. Reviewed-by:
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Jan Kara authored
Printing inode pointers in warnings has dubious value and with future changes we won't be able to easily get them without either locking or chances we oops along the way. So just remove inode pointers from the warning messages. Reviewed-by:
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Jan Kara authored
show_fdinfo() iterates group's list of marks. All marks found there are guaranteed to be alive and they stay so until we release group->mark_mutex. So remove uncecessary tests whether mark is alive. Reviewed-by:
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- 12 Mar, 2017 5 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linuxLinus Torvalds authored
Pull s390 fixes from Martin Schwidefsky: - four patches to get the new cputime code in shape for s390 - add the new statx system call - a few bug fixes * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390: wire up statx system call KVM: s390: Fix guest migration for huge guests resulting in panic s390/ipl: always use load normal for CCW-type re-IPL s390/timex: micro optimization for tod_to_ns s390/cputime: provide archicture specific cputime_to_nsecs s390/cputime: reset all accounting fields on fork s390/cputime: remove last traces of cputime_t s390: fix in-kernel program checks s390/crypt: fix missing unlock in ctr_paes_crypt on error path
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Thomas Gleixner: - a fix for the kexec/purgatory regression which was introduced in the merge window via an innocent sparse fix. We could have reverted that commit, but on deeper inspection it turned out that the whole machinery is neither documented nor robust. So a proper cleanup was done instead - the fix for the TLB flush issue which was discovered recently - a simple typo fix for a reboot quirk * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/tlb: Fix tlb flushing when lguest clears PGE kexec, x86/purgatory: Unbreak it and clean it up x86/reboot/quirks: Fix typo in ASUS EeeBook X205TA reboot quirk
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull irq fixes from Thomas Gleixner: - a workaround for a GIC erratum - a missing stub function for CONFIG_IRQDOMAIN=n - fixes for a couple of type inconsistencies * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: irqchip/crossbar: Fix incorrect type of register size irqchip/gicv3-its: Add workaround for QDF2400 ITS erratum 0065 irqdomain: Add empty irq_domain_check_msi_remap irqchip/crossbar: Fix incorrect type of local variables
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Daniel Borkmann authored
Fengguang reported random corruptions from various locations on x86-32 after commits d2852a22 ("arch: add ARCH_HAS_SET_MEMORY config") and 9d876e79 ("bpf: fix unlocking of jited image when module ronx not set") that uses the former. While x86-32 doesn't have a JIT like x86_64, the bpf_prog_lock_ro() and bpf_prog_unlock_ro() got enabled due to ARCH_HAS_SET_MEMORY, whereas Fengguang's test kernel doesn't have module support built in and therefore never had the DEBUG_SET_MODULE_RONX setting enabled. After investigating the crashes further, it turned out that using set_memory_ro() and set_memory_rw() didn't have the desired effect, for example, setting the pages as read-only on x86-32 would still let probe_kernel_write() succeed without error. This behavior would manifest itself in situations where the vmalloc'ed buffer was accessed prior to set_memory_*() such as in case of bpf_prog_alloc(). In cases where it wasn't, the page attribute changes seemed to have taken effect, leading to the conclusion that a TLB invalidate didn't happen. Moreover, it turned out that this issue reproduced with qemu in "-cpu kvm64" mode, but not for "-cpu host". When the issue occurs, change_page_attr_set_clr() did trigger a TLB flush as expected via __flush_tlb_all() through cpa_flush_range(), though. There are 3 variants for issuing a TLB flush: invpcid_flush_all() (depends on CPU feature bits X86_FEATURE_INVPCID, X86_FEATURE_PGE), cr4 based flush (depends on X86_FEATURE_PGE), and cr3 based flush. For "-cpu host" case in my setup, the flush used invpcid_flush_all() variant, whereas for "-cpu kvm64", the flush was cr4 based. Switching the kvm64 case to cr3 manually worked fine, and further investigating the cr4 one turned out that X86_CR4_PGE bit was not set in cr4 register, meaning the __native_flush_tlb_global_irq_disabled() wrote cr4 twice with the same value instead of clearing X86_CR4_PGE in the first write to trigger the flush. It turned out that X86_CR4_PGE was cleared from cr4 during init from lguest_arch_host_init() via adjust_pge(). The X86_FEATURE_PGE bit is also cleared from there due to concerns of using PGE in guest kernel that can lead to hard to trace bugs (see bff672e6 ("lguest: documentation V: Host") in init()). The CPU feature bits are cleared in dynamic boot_cpu_data, but they never propagated to __flush_tlb_all() as it uses static_cpu_has() instead of boot_cpu_has() for testing which variant of TLB flushing to use, meaning they still used the old setting of the host kernel. Clearing via setup_clear_cpu_cap(X86_FEATURE_PGE) so this would propagate to static_cpu_has() checks is too late at this point as sections have been patched already, so for now, it seems reasonable to switch back to boot_cpu_has(X86_FEATURE_PGE) as it was prior to commit c109bf95 ("x86/cpufeature: Remove cpu_has_pge"). This lets the TLB flush trigger via cr3 as originally intended, properly makes the new page attributes visible and thus fixes the crashes seen by Fengguang. Fixes: c109bf95 ("x86/cpufeature: Remove cpu_has_pge") Reported-by:
Fengguang Wu <fengguang.wu@intel.com> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Cc: bp@suse.de Cc: Kees Cook <keescook@chromium.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: netdev@vger.kernel.org Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: lkp@01.org Cc: Laura Abbott <labbott@redhat.com> Cc: stable@vger.kernel.org Link: http://lkml.kernrl.org/r/20170301125426.l4nf65rx4wahohyl@wfg-t540p.sh.intel.com Link: http://lkml.kernel.org/r/25c41ad9eca164be4db9ad84f768965b7eb19d9e.1489191673.git.daniel@iogearbox.netSigned-off-by:
Thomas Gleixner <tglx@linutronix.de>
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- 11 Mar, 2017 8 commits
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git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds authored
Pull KVM fixes from Radim Krčmář: "ARM updates from Marc Zyngier: - vgic updates: - Honour disabling the ITS - Don't deadlock when deactivating own interrupts via MMIO - Correctly expose the lact of IRQ/FIQ bypass on GICv3 - I/O virtualization: - Make KVM_CAP_NR_MEMSLOTS big enough for large guests with many PCIe devices - General bug fixes: - Gracefully handle exception generated with syndroms that the host doesn't understand - Properly invalidate TLBs on VHE systems x86: - improvements in emulation of VMCLEAR, VMX MSR bitmaps, and VCPU reset * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: nVMX: do not warn when MSR bitmap address is not backed KVM: arm64: Increase number of user memslots to 512 KVM: arm/arm64: Remove KVM_PRIVATE_MEM_SLOTS definition that are unused KVM: arm/arm64: Enable KVM_CAP_NR_MEMSLOTS on arm/arm64 KVM: Add documentation for KVM_CAP_NR_MEMSLOTS KVM: arm/arm64: VGIC: Fix command handling while ITS being disabled arm64: KVM: Survive unknown traps from guests arm: KVM: Survive unknown traps from guests KVM: arm/arm64: Let vcpu thread modify its own active state KVM: nVMX: reset nested_run_pending if the vCPU is going to be reset kvm: nVMX: VMCLEAR should not cause the vCPU to shut down KVM: arm/arm64: vgic-v3: Don't pretend to support IRQ/FIQ bypass arm64: KVM: VHE: Clear HCR_TGE when invalidating guest TLBs -
git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linuxLinus Torvalds authored
Pull extable.h fix from Paul Gortmaker: "Fixup for arch/score after extable.h introduction. It seems that Guenter is the only one on the planet doing builds for arch/score -- we don't have compile coverage for it in linux-next or in the kbuild-bot either. Guenter couldn't even recall where he got his toolchain, but was kind enough to share it with me so I could validate this change and also add arch/score to my build coverage. I sat on this a bit in case there was any other fallout in other arch dirs, but since this still seems to be the only one, I might as well send it on its way" * tag 'extable-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: score: Fix implicit includes now failing build after extable change
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git://git.kernel.org/pub/scm/linux/kernel/git/tytso/randomLinus Torvalds authored
Pull random updates from Ted Ts'o: "Change get_random_{int,log} to use the CRNG used by /dev/urandom and getrandom(2). It's faster and arguably more secure than cut-down MD5 that we had been using. Also do some code cleanup" * tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random: random: move random_min_urandom_seed into CONFIG_SYSCTL ifdef block random: convert get_random_int/long into get_random_u32/u64 random: use chacha20 for get_random_int/long random: fix comment for unused random_min_urandom_seed random: remove variable limit random: remove stale urandom_init_wait random: remove stale maybe_reseed_primary_crng -
Guenter Roeck authored
After changing from module.h to extable.h, score builds fail with: arch/score/kernel/traps.c: In function 'do_ri': arch/score/kernel/traps.c:248:4: error: implicit declaration of function 'user_disable_single_step' arch/score/mm/extable.c: In function 'fixup_exception': arch/score/mm/extable.c:32:38: error: dereferencing pointer to incomplete type arch/score/mm/extable.c:34:24: error: dereferencing pointer to incomplete type because extable.h doesn't drag in the same amount of headers as the module.h did. Add in the headers which were implicitly expected. Fixes: 90858794 ("module.h: remove extable.h include now users have migrated") Signed-off-by:
Guenter Roeck <linux@roeck-us.net> [PG: tweak commit log; refresh for sched header refactoring.] Signed-off-by:
Paul Gortmaker <paul.gortmaker@windriver.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/ttyLinus Torvalds authored
Pull tty/serial fixes frpm Greg KH: "Here are two bugfixes for tty stuff for 4.11-rc2. One of them resolves the pretty bad bug in the n_hdlc code that Alexander Popov found and fixed and has been reported everywhere. The other just fixes a samsung serial driver issue when DMA fails on some systems. Both have been in linux-next with no reported issues" * tag 'tty-4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: serial: samsung: Continue to work if DMA request fails tty: n_hdlc: get rid of racy n_hdlc.tbuf
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/stagingLinus Torvalds authored
Pull staging driver fixes from Greg KH: "Here are two small build warning fixes for some staging drivers that Arnd has found on his valiant quest to get the kernel to build properly with no warnings. Both of these have been in linux-next this week and resolve the reported issues" * tag 'staging-4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: staging: octeon: remove unused variable staging/vc04_services: add CONFIG_OF dependency
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usbLinus Torvalds authored
Pull USB fixes from Greg KH: "Here is a number of different USB fixes for 4.11-rc2. Seems like there were a lot of unresolved issues that people have been finding for this subsystem, and a bunch of good security auditing happening as well from Johan Hovold. There's the usual batch of gadget driver fixes and xhci issues resolved as well. All of these have been in linux-next with no reported issues" * tag 'usb-4.11-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (35 commits) usb: host: xhci-plat: Fix timeout on removal of hot pluggable xhci controllers usb: host: xhci-dbg: HCIVERSION should be a binary number usb: xhci: remove dummy extra_priv_size for size of xhci_hcd struct usb: xhci-mtk: check hcc_params after adding primary hcd USB: serial: digi_acceleport: fix OOB-event processing MAINTAINERS: usb251xb: remove reference inexistent file doc: dt-bindings: usb251xb: mark reg as required usb: usb251xb: dt: add unit suffix to oc-delay and power-on-time usb: usb251xb: remove max_{power,current}_{sp,bp} properties usb-storage: Add ignore-residue quirk for Initio INIC-3619 USB: iowarrior: fix NULL-deref in write USB: iowarrior: fix NULL-deref at probe usb: phy: isp1301: Add OF device ID table usb: ohci-at91: Do not drop unhandled USB suspend control requests USB: serial: safe_serial: fix information leak in completion handler USB: serial: io_ti: fix information leak in completion handler USB: serial: omninet: drop open callback USB: serial: omninet: fix reference leaks at open USB: serial: io_ti: fix NULL-deref in interrupt callback usb: dwc3: gadget: make to increment req->remaining in all cases ...
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git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlLinus Torvalds authored
Pull pinctrl fixes from Linus Walleij: "Two smaller pin control fixes for the v4.11 series: - Add a get_direction() function to the qcom driver - Fix two pin names in the uniphier driver" * tag 'pinctrl-v4.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: pinctrl: uniphier: change pin names of aio/xirq for LD11 pinctrl: qcom: add get_direction function
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- 10 Mar, 2017 1 commit
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Thomas Gleixner authored
The purgatory code defines global variables which are referenced via a symbol lookup in the kexec code (core and arch). A recent commit addressing sparse warnings made these static and thereby broke kexec_file. Why did this happen? Simply because the whole machinery is undocumented and lacks any form of forward declarations. The variable names are unspecific and lack a prefix, so adding forward declarations creates shadow variables in the core code. Aside of that the code relies on magic constants and duplicate struct definitions with no way to ensure that these things stay in sync. The section placement of the purgatory variables happened by chance and not by design. Unbreak kexec and cleanup the mess: - Add proper forward declarations and document the usage - Use common struct definition - Use the proper common defines instead of magic constants - Add a purgatory_ prefix to have a proper name space - Use ARRAY_SIZE() instead of a homebrewn reimplementation - Add proper sections to the purgatory variables [ From Mike ] Fixes: 72042a8c ("x86/purgatory: Make functions and variables static") Reported-by:
Mike Galbraith <<efault@gmx.de> Signed-off-by:
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