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* fscrypt: add support for AES-128-CBCDaniel Walter2017-07-211-6/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | fscrypt provides facilities to use different encryption algorithms which are selectable by userspace when setting the encryption policy. Currently, only AES-256-XTS for file contents and AES-256-CBC-CTS for file names are implemented. This is a clear case of kernel offers the mechanism and userspace selects a policy. Similar to what dm-crypt and ecryptfs have. This patch adds support for using AES-128-CBC for file contents and AES-128-CBC-CTS for file name encryption. To mitigate watermarking attacks, IVs are generated using the ESSIV algorithm. While AES-CBC is actually slightly less secure than AES-XTS from a security point of view, there is more widespread hardware support. Using AES-CBC gives us the acceptable performance while still providing a moderate level of security for persistent storage. Especially low-powered embedded devices with crypto accelerators such as CAAM or CESA often only support AES-CBC. Since using AES-CBC over AES-XTS is basically thought of a last resort, we use AES-128-CBC over AES-256-CBC since it has less encryption rounds and yields noticeable better performance starting from a file size of just a few kB. Signed-off-by: Daniel Walter <dwalter@sigma-star.at> [david@sigma-star.at: addressed review comments] Signed-off-by: David Gstir <david@sigma-star.at> Reviewed-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Conflicts: fs/crypto/crypto.c fs/crypto/fscrypt_private.h fs/crypto/keyinfo.c
* fscrypt: inline fscrypt_free_filename()Eric Biggers2017-07-211-1/+6
| | | | | | | | | | | fscrypt_free_filename() only needs to do a kfree() of crypto_buf.name, which works well as an inline function. We can skip setting the various pointers to NULL, since no user cares about it (the name is always freed just before it goes out of scope). Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: David Gstir <david@sigma-star.at> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* mm: larger stack guard gap, between vmasHugh Dickins2017-07-041-28/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 1be7107fbe18eed3e319a6c3e83c78254b693acb upstream. Stack guard page is a useful feature to reduce a risk of stack smashing into a different mapping. We have been using a single page gap which is sufficient to prevent having stack adjacent to a different mapping. But this seems to be insufficient in the light of the stack usage in userspace. E.g. glibc uses as large as 64kB alloca() in many commonly used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX] which is 256kB or stack strings with MAX_ARG_STRLEN. This will become especially dangerous for suid binaries and the default no limit for the stack size limit because those applications can be tricked to consume a large portion of the stack and a single glibc call could jump over the guard page. These attacks are not theoretical, unfortunatelly. Make those attacks less probable by increasing the stack guard gap to 1MB (on systems with 4k pages; but make it depend on the page size because systems with larger base pages might cap stack allocations in the PAGE_SIZE units) which should cover larger alloca() and VLA stack allocations. It is obviously not a full fix because the problem is somehow inherent, but it should reduce attack space a lot. One could argue that the gap size should be configurable from userspace, but that can be done later when somebody finds that the new 1MB is wrong for some special case applications. For now, add a kernel command line option (stack_guard_gap) to specify the stack gap size (in page units). Implementation wise, first delete all the old code for stack guard page: because although we could get away with accounting one extra page in a stack vma, accounting a larger gap can break userspace - case in point, a program run with "ulimit -S -v 20000" failed when the 1MB gap was counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK and strict non-overcommit mode. Instead of keeping gap inside the stack vma, maintain the stack guard gap as a gap between vmas: using vm_start_gap() in place of vm_start (or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few places which need to respect the gap - mainly arch_get_unmapped_area(), and and the vma tree's subtree_gap support for that. Original-patch-by: Oleg Nesterov <oleg@redhat.com> Original-patch-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Hugh Dickins <hughd@google.com> [wt: backport to 4.11: adjust context] [wt: backport to 4.9: adjust context ; kernel doc was not in admin-guide] [wt: backport to 4.4: adjust context ; drop ppc hugetlb_radix changes] [wt: backport to 3.18: adjust context ; no FOLL_POPULATE ; s390 uses generic arch_get_unmapped_area()] [wt: backport to 3.16: adjust context] [wt: backport to 3.10: adjust context ; code logic in PARISC's arch_get_unmapped_area() wasn't found ; code inserted into expand_upwards() and expand_downwards() runs under anon_vma lock; changes for gup.c:faultin_page go to memory.c:__get_user_pages(); included Hugh Dickins' fixes] Signed-off-by: Willy Tarreau <w@1wt.eu>
* uksm: remove Mtk aksm & uksm (because its fugly)Mister Oyster2017-07-045-267/+16
| | | | | | | | | | | | | | | | Revert "KSM: mediatek: implement Adaptive KSM" Revert "mm: uksm: fix maybe-uninitialized warning" Revert "UKSM: Add Governors for Higher CPU usage (HighCPU) for more merging, and low cpu usage (Battery) for less battery drain" Revert "uksm: use deferrable timer" Revert "mm: limit UKSM sleep time instead of failing" Revert "uksm: Fix warning" Revert "uksm: clean up and remove some (no)inlines" Revert "uksm: modify ema logic and tidy up" Revert "uksm: enhancements and cleanups" Revert "uksm: squashed fixups" Revert "UKSM: cast variable as const" Revert "UKSM: remove U64_MAX definition" Revert "add uksm 0.1.2.3 for v3.10 .ge.46.patch"
* nfs: Don't increment lock sequence ID after NFS4ERR_MOVEDChuck Lever2017-07-041-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | commit 059aa734824165507c65fd30a55ff000afd14983 upstream. Xuan Qi reports that the Linux NFSv4 client failed to lock a file that was migrated. The steps he observed on the wire: 1. The client sent a LOCK request to the source server 2. The source server replied NFS4ERR_MOVED 3. The client switched to the destination server 4. The client sent the same LOCK request to the destination server with a bumped lock sequence ID 5. The destination server rejected the LOCK request with NFS4ERR_BAD_SEQID RFC 3530 section 8.1.5 provides a list of NFS errors which do not bump a lock sequence ID. However, RFC 3530 is now obsoleted by RFC 7530. In RFC 7530 section 9.1.7, this list has been updated by the addition of NFS4ERR_MOVED. Reported-by: Xuan Qi <xuan.qi@oracle.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Willy Tarreau <w@1wt.eu>
* KVM: kvm_io_bus_unregister_dev() should never failDavid Hildenbrand2017-06-171-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | commit 90db10434b163e46da413d34db8d0e77404cc645 upstream. No caller currently checks the return value of kvm_io_bus_unregister_dev(). This is evil, as all callers silently go on freeing their device. A stale reference will remain in the io_bus, getting at least used again, when the iobus gets teared down on kvm_destroy_vm() - leading to use after free errors. There is nothing the callers could do, except retrying over and over again. So let's simply remove the bus altogether, print an error and make sure no one can access this broken bus again (returning -ENOMEM on any attempt to access it). Fixes: e93f8a0f821e ("KVM: convert io_bus to SRCU") Reported-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com> Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> [wt: no kvm_io_bus_read_cookie in 3.10, slightly different constructs] Signed-off-by: Willy Tarreau <w@1wt.eu>
* kvm: exclude ioeventfd from counting kvm_io_range limitAmos Kong2017-06-171-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | commit 6ea34c9b78c10289846db0abeebd6b84d5aca084 upstream. We can easily reach the 1000 limit by start VM with a couple hundred I/O devices (multifunction=on). The hardcode limit already been adjusted 3 times (6 ~ 200 ~ 300 ~ 1000). In userspace, we already have maximum file descriptor to limit ioeventfd count. But kvm_io_bus devices also are used for pit, pic, ioapic, coalesced_mmio. They couldn't be limited by maximum file descriptor. Currently only ioeventfds take too much kvm_io_bus devices, so just exclude it from counting kvm_io_range limit. Also fixed one indent issue in kvm_host.h Signed-off-by: Amos Kong <akong@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com> [wt: next patch depends on this one] Signed-off-by: Willy Tarreau <w@1wt.eu>
* can: Fix kernel panic at security_sock_rcv_skbEric Dumazet2017-06-171-4/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit f1712c73714088a7252d276a57126d56c7d37e64 upstream. Zhang Yanmin reported crashes [1] and provided a patch adding a synchronize_rcu() call in can_rx_unregister() The main problem seems that the sockets themselves are not RCU protected. If CAN uses RCU for delivery, then sockets should be freed only after one RCU grace period. Recent kernels could use sock_set_flag(sk, SOCK_RCU_FREE), but let's ease stable backports with the following fix instead. [1] BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff81495e25>] selinux_socket_sock_rcv_skb+0x65/0x2a0 Call Trace: <IRQ> [<ffffffff81485d8c>] security_sock_rcv_skb+0x4c/0x60 [<ffffffff81d55771>] sk_filter+0x41/0x210 [<ffffffff81d12913>] sock_queue_rcv_skb+0x53/0x3a0 [<ffffffff81f0a2b3>] raw_rcv+0x2a3/0x3c0 [<ffffffff81f06eab>] can_rcv_filter+0x12b/0x370 [<ffffffff81f07af9>] can_receive+0xd9/0x120 [<ffffffff81f07beb>] can_rcv+0xab/0x100 [<ffffffff81d362ac>] __netif_receive_skb_core+0xd8c/0x11f0 [<ffffffff81d36734>] __netif_receive_skb+0x24/0xb0 [<ffffffff81d37f67>] process_backlog+0x127/0x280 [<ffffffff81d36f7b>] net_rx_action+0x33b/0x4f0 [<ffffffff810c88d4>] __do_softirq+0x184/0x440 [<ffffffff81f9e86c>] do_softirq_own_stack+0x1c/0x30 <EOI> [<ffffffff810c76fb>] do_softirq.part.18+0x3b/0x40 [<ffffffff810c8bed>] do_softirq+0x1d/0x20 [<ffffffff81d30085>] netif_rx_ni+0xe5/0x110 [<ffffffff8199cc87>] slcan_receive_buf+0x507/0x520 [<ffffffff8167ef7c>] flush_to_ldisc+0x21c/0x230 [<ffffffff810e3baf>] process_one_work+0x24f/0x670 [<ffffffff810e44ed>] worker_thread+0x9d/0x6f0 [<ffffffff810e4450>] ? rescuer_thread+0x480/0x480 [<ffffffff810ebafc>] kthread+0x12c/0x150 [<ffffffff81f9ccef>] ret_from_fork+0x3f/0x70 Reported-by: Zhang Yanmin <yanmin.zhang@intel.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Willy Tarreau <w@1wt.eu>
* ACPI / PNP: Reserve ACPI resources at the fs_initcall_sync stageRafael J. Wysocki2017-06-171-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 0294112ee3135fbd15eaa70015af8283642dd970 upstream. This effectively reverts the following three commits: 7bc10388ccdd ACPI / resources: free memory on error in add_region_before() 0f1b414d1907 ACPI / PNP: Avoid conflicting resource reservations b9a5e5e18fbf ACPI / init: Fix the ordering of acpi_reserve_resources() (commit b9a5e5e18fbf introduced regressions some of which, but not all, were addressed by commit 0f1b414d1907 and commit 7bc10388ccdd was a fixup on top of the latter) and causes ACPI fixed hardware resources to be reserved at the fs_initcall_sync stage of system initialization. The story is as follows. First, a boot regression was reported due to an apparent resource reservation ordering change after a commit that shouldn't lead to such changes. Investigation led to the conclusion that the problem happened because acpi_reserve_resources() was executed at the device_initcall() stage of system initialization which wasn't strictly ordered with respect to driver initialization (and with respect to the initialization of the pcieport driver in particular), so a random change causing the device initcalls to be run in a different order might break things. The response to that was to attempt to run acpi_reserve_resources() as soon as we knew that ACPI would be in use (commit b9a5e5e18fbf). However, that turned out to be too early, because it caused resource reservations made by the PNP system driver to fail on at least one system and that failure was addressed by commit 0f1b414d1907. That fix still turned out to be insufficient, though, because calling acpi_reserve_resources() before the fs_initcall stage of system initialization caused a boot regression to happen on the eCAFE EC-800-H20G/S netbook. That meant that we only could call acpi_reserve_resources() at the fs_initcall initialization stage or later, but then we might just as well call it after the PNP initalization in which case commit 0f1b414d1907 wouldn't be necessary any more. For this reason, the changes made by commit 0f1b414d1907 are reverted (along with a memory leak fixup on top of that commit), the changes made by commit b9a5e5e18fbf that went too far are reverted too and acpi_reserve_resources() is changed into fs_initcall_sync, which will cause it to be executed after the PNP subsystem initialization (which is an fs_initcall) and before device initcalls (including the pcieport driver initialization) which should avoid the initial issue. Link: https://bugzilla.kernel.org/show_bug.cgi?id=100581 Link: http://marc.info/?t=143092384600002&r=1&w=2 Link: https://bugzilla.kernel.org/show_bug.cgi?id=99831 Link: http://marc.info/?t=143389402600001&r=1&w=2 Fixes: b9a5e5e18fbf "ACPI / init: Fix the ordering of acpi_reserve_resources()" Reported-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Willy Tarreau <w@1wt.eu>
* ACPI / PNP: Avoid conflicting resource reservationsRafael J. Wysocki2017-06-171-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 0f1b414d190724617eb1cdd615592fa8cd9d0b50 upstream. Commit b9a5e5e18fbf "ACPI / init: Fix the ordering of acpi_reserve_resources()" overlooked the fact that the memory and/or I/O regions reserved by acpi_reserve_resources() may conflict with those reserved by the PNP "system" driver. If that conflict actually takes place, it causes the reservations made by the "system" driver to fail while before commit b9a5e5e18fbf all reservations made by it and by acpi_reserve_resources() would be successful. In turn, that allows the resources that haven't been reserved by the "system" driver to be used by others (e.g. PCI) which sometimes leads to functional problems (up to and including boot failures). To fix that issue, introduce a common resource reservation routine, acpi_reserve_region(), to be used by both acpi_reserve_resources() and the "system" driver, that will track all resources reserved by it and avoid making conflicting requests. Link: https://bugzilla.kernel.org/show_bug.cgi?id=99831 Link: http://marc.info/?t=143389402600001&r=1&w=2 Fixes: b9a5e5e18fbf "ACPI / init: Fix the ordering of acpi_reserve_resources()" Reported-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Willy Tarreau <w@1wt.eu>
* locking/static_keys: Add static_key_{en,dis}able() helpersPeter Zijlstra2017-06-171-0/+16
| | | | | | | | | | | | | | | | | | | | | | | commit e33886b38cc82a9fc3b2d655dfc7f50467594138 upstream. Add two helpers to make it easier to treat the refcount as boolean. [js] do not involve WARN_ON_ONCE as it causes build failures Suggested-by: Jason Baron <jasonbaron0@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Jiri Slaby <jslaby@suse.cz> [wt: only backported for use in next fix ; s/static_key_count(key)/atomic_read(&key->enabled)/] Signed-off-by: Willy Tarreau <w@1wt.eu>
* nlm: Ensure callback code also checks that the files matchTrond Myklebust2017-06-171-1/+2
| | | | | | | | | | | | | | commit 251af29c320d86071664f02c76f0d063a19fefdf upstream. It is not sufficient to just check that the lock pids match when granting a callback, we also need to ensure that we're granting the callback on the right file. Reported-by: Pankaj Singh <psingh.ait@gmail.com> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Willy Tarreau <w@1wt.eu>
* gro: Disable frag0 optimization on IPv6 ext headersHerbert Xu2017-06-171-2/+7
| | | | | | | | | | | | | | | | | | | | | | | commit 57ea52a865144aedbcd619ee0081155e658b6f7d upstream. The GRO fast path caches the frag0 address. This address becomes invalid if frag0 is modified by pskb_may_pull or its variants. So whenever that happens we must disable the frag0 optimization. This is usually done through the combination of gro_header_hard and gro_header_slow, however, the IPv6 extension header path did the pulling directly and would continue to use the GRO fast path incorrectly. This patch fixes it by disabling the fast path when we enter the IPv6 extension header path. Fixes: 78a478d0efd9 ("gro: Inline skb_gro_header and cache frag0 virtual address") Reported-by: Slava Shwartsman <slavash@mellanox.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Willy Tarreau <w@1wt.eu>
* hotplug: Make register and unregister notifier API symmetricMichal Hocko2017-06-171-12/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 777c6e0daebb3fcefbbd6f620410a946b07ef6d0 upstream. Yu Zhao has noticed that __unregister_cpu_notifier only unregisters its notifiers when HOTPLUG_CPU=y while the registration might succeed even when HOTPLUG_CPU=n if MODULE is enabled. This means that e.g. zswap might keep a stale notifier on the list on the manual clean up during the pool tear down and thus corrupt the list. Resulting in the following [ 144.964346] BUG: unable to handle kernel paging request at ffff880658a2be78 [ 144.971337] IP: [<ffffffffa290b00b>] raw_notifier_chain_register+0x1b/0x40 <snipped> [ 145.122628] Call Trace: [ 145.125086] [<ffffffffa28e5cf8>] __register_cpu_notifier+0x18/0x20 [ 145.131350] [<ffffffffa2a5dd73>] zswap_pool_create+0x273/0x400 [ 145.137268] [<ffffffffa2a5e0fc>] __zswap_param_set+0x1fc/0x300 [ 145.143188] [<ffffffffa2944c1d>] ? trace_hardirqs_on+0xd/0x10 [ 145.149018] [<ffffffffa2908798>] ? kernel_param_lock+0x28/0x30 [ 145.154940] [<ffffffffa2a3e8cf>] ? __might_fault+0x4f/0xa0 [ 145.160511] [<ffffffffa2a5e237>] zswap_compressor_param_set+0x17/0x20 [ 145.167035] [<ffffffffa2908d3c>] param_attr_store+0x5c/0xb0 [ 145.172694] [<ffffffffa290848d>] module_attr_store+0x1d/0x30 [ 145.178443] [<ffffffffa2b2b41f>] sysfs_kf_write+0x4f/0x70 [ 145.183925] [<ffffffffa2b2a5b9>] kernfs_fop_write+0x149/0x180 [ 145.189761] [<ffffffffa2a99248>] __vfs_write+0x18/0x40 [ 145.194982] [<ffffffffa2a9a412>] vfs_write+0xb2/0x1a0 [ 145.200122] [<ffffffffa2a9a732>] SyS_write+0x52/0xa0 [ 145.205177] [<ffffffffa2ff4d97>] entry_SYSCALL_64_fastpath+0x12/0x17 This can be even triggered manually by changing /sys/module/zswap/parameters/compressor multiple times. Fix this issue by making unregister APIs symmetric to the register so there are no surprises. [js] backport to 3.12 Fixes: 47e627bc8c9a ("[PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU") Reported-and-tested-by: Yu Zhao <yuzhao@google.com> Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: linux-mm@kvack.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dan Streetman <ddstreet@ieee.org> Link: http://lkml.kernel.org/r/20161207135438.4310-1-mhocko@kernel.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Willy Tarreau <w@1wt.eu>
* Revert "jiffies conversions: Use compile time constants when possible"Mister Oyster2017-06-021-132/+4
| | | | | Build breaks when any of this code is included This reverts commit 9722cd7360077819a5af4937c0f742149fcec82c.
* vfs: add find_inode_nowait() functionTheodore Ts'o2017-05-291-0/+5
| | | | | | | | | | Add a new function find_inode_nowait() which is an even more general version of ilookup5_nowait(). It is designed for callers which need very fine grained control over when the function is allowed to block or increment the inode's reference count. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs: add dirtytime_expire_seconds sysctlTheodore Ts'o2017-05-291-0/+3
| | | | | | | | Add a tuning knob so we can adjust the dirtytime expiration timeout, which is very useful for testing lazytime. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
* fs: make sure the timestamps for lazytime inodes eventually get writtenTheodore Ts'o2017-05-291-0/+1
| | | | | | | | | | | | | | | | | | Jan Kara pointed out that if there is an inode which is constantly getting dirtied with I_DIRTY_PAGES, an inode with an updated timestamp will never be written since inode->dirtied_when is constantly getting updated. We fix this by adding an extra field to the inode, dirtied_time_when, so inodes with a stale dirtytime can get detected and handled. In addition, if we have a dirtytime inode caused by an atime update, and there is no write activity on the file system, we need to have a secondary system to make sure these inodes get written out. We do this by setting up a second delayed work structure which wakes up the CPU much more rarely compared to writeback_expire_centisecs. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
* ext4, jbd2: ensure entering into panic after recording an error in superblockDaeho Jeong2017-05-291-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 4327ba52afd03fc4b5afa0ee1d774c9c5b0e85c5 upstream. If a EXT4 filesystem utilizes JBD2 journaling and an error occurs, the journaling will be aborted first and the error number will be recorded into JBD2 superblock and, finally, the system will enter into the panic state in "errors=panic" option. But, in the rare case, this sequence is little twisted like the below figure and it will happen that the system enters into panic state, which means the system reset in mobile environment, before completion of recording an error in the journal superblock. In this case, e2fsck cannot recognize that the filesystem failure occurred in the previous run and the corruption wouldn't be fixed. Task A Task B ext4_handle_error() -> jbd2_journal_abort() -> __journal_abort_soft() -> __jbd2_journal_abort_hard() | -> journal->j_flags |= JBD2_ABORT; | | __ext4_abort() | -> jbd2_journal_abort() | | -> __journal_abort_soft() | | -> if (journal->j_flags & JBD2_ABORT) | | return; | -> panic() | -> jbd2_journal_update_sb_errno() Tested-by: Hobin Woo <hobin.woo@samsung.com> Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* vfs: add support for a lazytime mount optionTheodore Ts'o2017-05-292-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | Add a new mount option which enables a new "lazytime" mode. This mode causes atime, mtime, and ctime updates to only be made to the in-memory version of the inode. The on-disk times will only get updated when (a) if the inode needs to be updated for some non-time related change, (b) if userspace calls fsync(), syncfs() or sync(), or (c) just before an undeleted inode is evicted from memory. This is OK according to POSIX because there are no guarantees after a crash unless userspace explicitly requests via a fsync(2) call. For workloads which feature a large number of random write to a preallocated file, the lazytime mount option significantly reduces writes to the inode table. The repeated 4k writes to a single block will result in undesirable stress on flash devices and SMR disk drives. Even on conventional HDD's, the repeated writes to the inode table block will trigger Adjacent Track Interference (ATI) remediation latencies, which very negatively impact long tail latencies --- which is a very big deal for web serving tiers (for example). Google-Bug-Id: 18297052 Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* writeback: Do not sort b_io list only because of block device inodeJan Kara2017-05-291-0/+6
| | | | | | | | | | It is very likely that block device inode will be part of BDI dirty list as well. However it doesn't make sence to sort inodes on the b_io list just because of this inode (as it contains buffers all over the device anyway). So save some CPU cycles which is valuable since we hold relatively contented wb->list_lock. Signed-off-by: Jan Kara <jack@suse.cz>
* ext4 crypto: revalidate dentry after adding or removing the keyTheodore Ts'o2017-05-291-0/+17
| | | | | | | | | | | | Add a validation check for dentries for encrypted directory to make sure we're not caching stale data after a key has been added or removed. Also check to make sure that status of the encryption key is updated when readdir(2) is executed. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Theodore Ts'o <tytso@google.com> Change-Id: Ic7a90d79d9447272fc512ae2abbd299523de02b8
* mm: change invalidatepage prototype to accept lengthLukas Czerner2017-05-273-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently there is no way to truncate partial page where the end truncate point is not at the end of the page. This is because it was not needed and the functionality was enough for file system truncate operation to work properly. However more file systems now support punch hole feature and it can benefit from mm supporting truncating page just up to the certain point. Specifically, with this functionality truncate_inode_pages_range() can be changed so it supports truncating partial page at the end of the range (currently it will BUG_ON() if 'end' is not at the end of the page). This commit changes the invalidatepage() address space operation prototype to accept range to be invalidated and update all the instances for it. We also change the block_invalidatepage() in the same way and actually make a use of the new length argument implementing range invalidation. Actual file system implementations will follow except the file systems where the changes are really simple and should not change the behaviour in any way .Implementation for truncate_page_range() which will be able to accept page unaligned ranges will follow as well. Change-Id: Id47992f86b307985b3215bcf141d56d1849d71df Signed-off-by: Lukas Czerner <lczerner@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com> (cherry picked from commit d47992f86b307985b3215bcf141d56d1849d71df) f2fs: removed f2fs modifications bcs of f2fs backports Signed-off-by: Mister Oyster <oysterized@gmail.com>
* Add missing definitions for PTR_ERR_OR_ZERO() and NEED_KEY_SEARCHTheodore Ts'o2017-05-272-0/+12
| | | | | | | | These definitions are needed for the ext4 encryption patches Change-Id: Ib4254abadaeaf234f8539834f481c24dc93233eb Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Theodore Ts'o <tytso@google.com>
* non-ext4 portions of "direct-io: Implement generic deferred AIO completions"Theodore Ts'o2017-05-272-2/+7
| | | | | | Originally from 7b7a8665edd8db73 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* ext4: use old interface for ext4_readdir()Theodore Ts'o2017-05-271-1/+2
| | | | Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* sync: don't block the flusher thread waiting on IODave Chinner2017-05-271-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When sync does it's WB_SYNC_ALL writeback, it issues data Io and then immediately waits for IO completion. This is done in the context of the flusher thread, and hence completely ties up the flusher thread for the backing device until all the dirty inodes have been synced. On filesystems that are dirtying inodes constantly and quickly, this means the flusher thread can be tied up for minutes per sync call and hence badly affect system level write IO performance as the page cache cannot be cleaned quickly. We already have a wait loop for IO completion for sync(2), so cut this out of the flusher thread and delegate it to wait_sb_inodes(). Hence we can do rapid IO submission, and then wait for it all to complete. Effect of sync on fsmark before the patch: FSUse% Count Size Files/sec App Overhead ..... 0 640000 4096 35154.6 1026984 0 720000 4096 36740.3 1023844 0 800000 4096 36184.6 916599 0 880000 4096 1282.7 1054367 0 960000 4096 3951.3 918773 0 1040000 4096 40646.2 996448 0 1120000 4096 43610.1 895647 0 1200000 4096 40333.1 921048 And a single sync pass took: real 0m52.407s user 0m0.000s sys 0m0.090s After the patch, there is no impact on fsmark results, and each individual sync(2) operation run concurrently with the same fsmark workload takes roughly 7s: real 0m6.930s user 0m0.000s sys 0m0.039s IOWs, sync is 7-8x faster on a busy filesystem and does not have an adverse impact on ongoing async data write operations. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> (cherry picked from commit 7747bd4bceb3079572695d3942294a6c7b265557)
* ext4: backport mm portion of: fix data integrity sync in ordered modeTheodore Ts'o2017-05-271-1/+11
| | | | | | | | Commit 1c8349a17137: "ext4: fix data integrity sync in ordered mode" included changes to include/linux/page-flags.h and mm/page-writeback.c. Apply them as part of the 3.18 ext4 backport. Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* include/linux/fs.h: add dir_relax() for 3.18 backportMister Oyster2017-05-271-0/+7
| | | | | | partial commit from ec991b05a282642359e81e65855f189f7881009c include/linux/fs.h: add dir_emit() and dir_relax() for 3.18 backport Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* BACKPORT: ext4 from 3.18 to mtk-3.10Mister Oyster2017-05-272-90/+148
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* fs: add inode_set_flags() for ext4 3.18 backportTheodore Ts'o2017-05-271-0/+3
| | | | | | Excerpted from commit 5f16f3225b062 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* sched: add bit_wait_io for 3.18 ext4 backportTheodore Ts'o2017-05-271-1/+29
| | | | | | | Excerpted from commit 743162013: "sched: Remove proliferation of wait_on_bit() action functions" Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* buffer_head.h: add getblk_unmovable() for 3.18 ext4 backportTheodore Ts'o2017-05-271-0/+6
| | | | Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* mm.h: add truncate_inode_pages_final() for 3.18 ext4 backportTheodore Ts'o2017-05-271-0/+6
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* bitops.h: add smp_mb__after_atomic() for 3.18 backportTheodore Ts'o2017-05-271-0/+3
| | | | Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* buffer_head.h: add sb_bread_unmovable() for 3.18 ext4 backportTheodore Ts'o2017-05-271-0/+6
| | | | Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* mm: add find_get_page_flags() for 3.18 ext4 backportTheodore Ts'o2017-05-271-2/+12
| | | | Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* fs: add {lock,unlock}_two_nondirectories for 3.18 backportTheodore Ts'o2017-05-271-1/+6
| | | | Signed-off-by: Theodore Ts'o <tytso@mit.edu>
* UPSTREAM: math64: New separate div64_u64_rem helperMike Snitzer2017-05-241-0/+13
| | | | | | | | | | | | | | | | | | | | | | Commit f792685006274a850e6cc0ea9ade275ccdfc90bc ("math64: New div64_u64_rem helper") implemented div64_u64 in terms of div64_u64_rem. But div64_u64_rem was removed because it slowed down div64_u64 (and there were no other users of div64_u64_rem). Device Mapper's I/O statistics support has a need for div64_u64_rem; reintroduce this helper as a separate method that doesn't slow down div64_u64, especially on 32-bit systems. BUG: 27175947 Signed-off-by: Mike Snitzer <snitzer@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com> Change-Id: I05274c1a7235dfa972f5ddc4778e0154240fd9b6 Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
* include/linux/mm.h: remove ifdef conditionRashika Kheria2017-05-241-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ifdef conditions in include/linux/mm.h presents three cases: - !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) There is no actual definition of function but include/linux/mm.h has a static inline stub defined. - defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) linux/mm.h does not define a prototype, but mm/page_alloc.c defines the function. Hence, compiler reports the following warning: mm/page_alloc.c:4300:15: warning: no previous prototype for `__early_pfn_to_nid' [-Wmissing-prototypes] - defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) The architecture defines the function, and linux/mm.h has a prototype. Thus, join the conditions of Case 2 and 3 ie eliminate the ifdef condition of CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID to eliminate the missing prototype warning from file mm/page_alloc.c. Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
* mm/readahead.c: inline ra_submitFabian Frederick2017-05-241-3/+0
| | | | | | | | | | | | | | Commit f9acc8c7b35a ("readahead: sanify file_ra_state names") left ra_submit with a single function call. Move ra_submit to internal.h and inline it to save some stack. Thanks to Andrew Morton for commenting different versions. Signed-off-by: Fabian Frederick <fabf@skynet.be> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
* mm/memblock.c: introduce bottom-up allocation modeTang Chen2017-05-242-0/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Linux kernel cannot migrate pages used by the kernel. As a result, kernel pages cannot be hot-removed. So we cannot allocate hotpluggable memory for the kernel. ACPI SRAT (System Resource Affinity Table) contains the memory hotplug info. But before SRAT is parsed, memblock has already started to allocate memory for the kernel. So we need to prevent memblock from doing this. In a memory hotplug system, any numa node the kernel resides in should be unhotpluggable. And for a modern server, each node could have at least 16GB memory. So memory around the kernel image is highly likely unhotpluggable. So the basic idea is: Allocate memory from the end of the kernel image and to the higher memory. Since memory allocation before SRAT is parsed won't be too much, it could highly likely be in the same node with kernel image. The current memblock can only allocate memory top-down. So this patch introduces a new bottom-up allocation mode to allocate memory bottom-up. And later when we use this allocation direction to allocate memory, we will limit the start address above the kernel. Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com> Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: Toshi Kani <toshi.kani@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Tejun Heo <tj@kernel.org> Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Thomas Renninger <trenn@suse.de> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: Taku Izumi <izumi.taku@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
* memblock, numa: binary search node idYinghai Lu2017-05-241-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | Current early_pfn_to_nid() on arch that support memblock go over memblock.memory one by one, so will take too many try near the end. We can use existing memblock_search to find the node id for given pfn, that could save some time on bigger system that have many entries memblock.memory array. Here are the timing differences for several machines. In each case with the patch less time was spent in __early_pfn_to_nid(). 3.11-rc5 with patch difference (%) -------- ---------- -------------- UV1: 256 nodes 9TB: 411.66 402.47 -9.19 (2.23%) UV2: 255 nodes 16TB: 1141.02 1138.12 -2.90 (0.25%) UV2: 64 nodes 2TB: 128.15 126.53 -1.62 (1.26%) UV2: 32 nodes 2TB: 121.87 121.07 -0.80 (0.66%) Time in seconds. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Cc: Tejun Heo <tj@kernel.org> Acked-by: Russ Anderson <rja@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
* mm: disable zone_reclaim_mode by defaultMel Gorman2017-05-241-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When it was introduced, zone_reclaim_mode made sense as NUMA distances punished and workloads were generally partitioned to fit into a NUMA node. NUMA machines are now common but few of the workloads are NUMA-aware and it's routine to see major performance degradation due to zone_reclaim_mode being enabled but relatively few can identify the problem. Those that require zone_reclaim_mode are likely to be able to detect when it needs to be enabled and tune appropriately so lets have a sensible default for the bulk of users. This patch (of 2): zone_reclaim_mode causes processes to prefer reclaiming memory from local node instead of spilling over to other nodes. This made sense initially when NUMA machines were almost exclusively HPC and the workload was partitioned into nodes. The NUMA penalties were sufficiently high to justify reclaiming the memory. On current machines and workloads it is often the case that zone_reclaim_mode destroys performance but not all users know how to detect this. Favour the common case and disable it by default. Users that are sophisticated enough to know they need zone_reclaim_mode will detect it. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
* swap: maybe_preload & refactoringDmitry Safonov2017-05-241-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | zswap_get_swap_cache_page and read_swap_cache_async have pretty much the same code with only significant difference in return value and usage of swap_readpage. I a helper __read_swap_cache_async() with the common code. Behavior change: now zswap_get_swap_cache_page will use radix_tree_maybe_preload instead radix_tree_preload. Looks like, this wasn't changed only by the reason of code duplication. Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@fb.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David Herrmann <dh.herrmann@gmail.com> Cc: Seth Jennings <sjennings@variantweb.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Park Ju Hyung <qkrwngud825@gmail.com> Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
* fs/mpage.c: factor page_endio() out of mpage_end_io()Matthew Wilcox2017-05-241-0/+2
| | | | | | | | | | | | | | | page_endio() takes care of updating all the appropriate page flags once I/O has finished to a page. Switch to using mapping_set_error() instead of setting AS_EIO directly; this will handle thin-provisioned devices correctly. Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Dheeraj Reddy <dheeraj.reddy@intel.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
* fs/block_dev.c: add bdev_read_page() and bdev_write_page()Matthew Wilcox2017-05-241-0/+4
| | | | | | | | | | | | | | | | A block device driver may choose to provide a rw_page operation. These will be called when the filesystem is attempting to do page sized I/O to page cache pages (ie not for direct I/O). This does preclude I/Os that are larger than page size, so this may only be a performance gain for some devices. Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Tested-by: Dheeraj Reddy <dheeraj.reddy@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
* mm/mempolicy.c: convert the shared_policy lock to a rwlockNathan Zimmer2017-05-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When running the SPECint_rate gcc on some very large boxes it was noticed that the system was spending lots of time in mpol_shared_policy_lookup(). The gamess benchmark can also show it and is what I mostly used to chase down the issue since the setup for that I found to be easier. To be clear the binaries were on tmpfs because of disk I/O requirements. We then used text replication to avoid icache misses and having all the copies banging on the memory where the instruction code resides. This results in us hitting a bottleneck in mpol_shared_policy_lookup() since lookup is serialised by the shared_policy lock. I have only reproduced this on very large (3k+ cores) boxes. The problem starts showing up at just a few hundred ranks getting worse until it threatens to livelock once it gets large enough. For example on the gamess benchmark at 128 ranks this area consumes only ~1% of time, at 512 ranks it consumes nearly 13%, and at 2k ranks it is over 90%. To alleviate the contention in this area I converted the spinlock to an rwlock. This allows a large number of lookups to happen simultaneously. The results were quite good reducing this consumtion at max ranks to around 2%. [akpm@linux-foundation.org: tidy up code comments] Signed-off-by: Nathan Zimmer <nzimmer@sgi.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Nadia Yvette Chambers <nyc@holomorphy.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
* timer: Added usleep[_range] timerPatrick Pannuto2017-05-221-0/+5
| | | | | | | | | | | | | | | usleep[_range] are finer precision implementations of msleep and are designed to be drop-in replacements for udelay where a precise sleep / busy-wait is unnecessary. They also allow an easy interface to specify slack when a precise (ish) wakeup is unnecessary to help minimize wakeups As ACK'd upstream: https://patchwork.kernel.org/patch/112813/ Change-Id: I277737744ca58061323837609b121a0fc9d27f33 Signed-off-by: Patrick Pannuto <ppannuto@codeaurora.org> (cherry picked from commit 08c118890b06595dfc26d47ee63f59e73256c270)
* kernel: Only expose su when daemon is runningTom Marshall2017-05-214-0/+19
| | | | | | | | | | | | | | It has been claimed that the PG implementation of 'su' has security vulnerabilities even when disabled. Unfortunately, the people that find these vulnerabilities often like to keep them private so they can profit from exploits while leaving users exposed to malicious hackers. In order to reduce the attack surface for vulnerabilites, it is therefore necessary to make 'su' completely inaccessible when it is not in use (except by the root and system users). Change-Id: I79716c72f74d0b7af34ec3a8054896c6559a181d
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