- 10 5月, 2020 4 次提交
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由 Linus Torvalds 提交于
This is another fine warning, related to the 'zero-length-bounds' one, but hitting the same historical code in the kernel. Because C didn't historically support flexible array members, we have code that instead uses a one-sized array, the same way we have cases of zero-sized arrays. The one-sized arrays come from either not wanting to use the gcc zero-sized array extension, or from a slight convenience-feature, where particularly for strings, the size of the structure now includes the allocation for the final NUL character. So with a "char name[1];" at the end of a structure, you can do things like v = my_malloc(sizeof(struct vendor) + strlen(name)); and avoid the "+1" for the terminator. Yes, the modern way to do that is with a flexible array, and using 'offsetof()' instead of 'sizeof()', and adding the "+1" by hand. That also technically gets the size "more correct" in that it avoids any alignment (and thus padding) issues, but this is another long-term cleanup thing that will not happen for 5.7. So disable the warning for now, even though it's potentially quite useful. Having a slew of warnings that then hide more urgent new issues is not an improvement. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
This is a fine warning, but we still have a number of zero-length arrays in the kernel that come from the traditional gcc extension. Yes, they are getting converted to flexible arrays, but in the meantime the gcc-10 warning about zero-length bounds is very verbose, and is hiding other issues. I missed one actual build failure because it was hidden among hundreds of lines of warning. Thankfully I caught it on the second go before pushing things out, but it convinced me that I really need to disable the new warnings for now. We'll hopefully be all done with our conversion to flexible arrays in the not too distant future, and we can then re-enable this warning. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Linus Torvalds 提交于
We have some rather random rules about when we accept the "maybe-initialized" warnings, and when we don't. For example, we consider it unreliable for gcc versions < 4.9, but also if -O3 is enabled, or if optimizing for size. And then various kernel config options disabled it, because they know that they trigger that warning by confusing gcc sufficiently (ie PROFILE_ALL_BRANCHES). And now gcc-10 seems to be introducing a lot of those warnings too, so it falls under the same heading as 4.9 did. At the same time, we have a very straightforward way to _enable_ that warning when wanted: use "W=2" to enable more warnings. So stop playing these ad-hoc games, and just disable that warning by default, with the known and straight-forward "if you want to work on the extra compiler warnings, use W=123". Would it be great to have code that is always so obvious that it never confuses the compiler whether a variable is used initialized or not? Yes, it would. In a perfect world, the compilers would be smarter, and our source code would be simpler. That's currently not the world we live in, though. Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.dk/linux-block由 Linus Torvalds 提交于
Pull io_uring fixes from Jens Axboe: - Fix finish_wait() balancing in file cancelation (Xiaoguang) - Ensure early cleanup of resources in ring map failure (Xiaoguang) - Ensure IORING_OP_SLICE does the right file mode checks (Pavel) - Remove file opening from openat/openat2/statx, it's not needed and messes with O_PATH * tag 'io_uring-5.7-2020-05-08' of git://git.kernel.dk/linux-block: io_uring: don't use 'fd' for openat/openat2/statx splice: move f_mode checks to do_{splice,tee}() io_uring: handle -EFAULT properly in io_uring_setup() io_uring: fix mismatched finish_wait() calls in io_uring_cancel_files()
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- 09 5月, 2020 6 次提交
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git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi由 Linus Torvalds 提交于
Pull SCSI fixes from James Bottomley: "Four minor fixes, all in drivers (qla2xxx, ibmvfc, ibmvscsi)" * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: scsi: ibmvscsi: Fix WARN_ON during event pool release scsi: ibmvfc: Don't send implicit logouts prior to NPIV login scsi: qla2xxx: Delete all sessions before unregister local nvme port scsi: qla2xxx: Fix hang when issuing nvme disconnect-all in NPIV
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git://github.com/ceph/ceph-client由 Linus Torvalds 提交于
Pull ceph fixes from Ilya Dryomov: "Fixes for an endianness handling bug that prevented mounts on big-endian arches, a spammy log message and a couple error paths. Also included a MAINTAINERS update" * tag 'ceph-for-5.7-rc5' of git://github.com/ceph/ceph-client: ceph: demote quotarealm lookup warning to a debug message MAINTAINERS: remove myself as ceph co-maintainer ceph: fix double unlock in handle_cap_export() ceph: fix special error code in ceph_try_get_caps() ceph: fix endianness bug when handling MDS session feature bits
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由 Luis Henriques 提交于
A misconfigured cephx can easily result in having the kernel client flooding the logs with: ceph: Can't lookup inode 1 (err: -13) Change this message to debug level. Cc: stable@vger.kernel.org URL: https://tracker.ceph.com/issues/44546Signed-off-by: NLuis Henriques <lhenriques@suse.com> Reviewed-by: NJeff Layton <jlayton@kernel.org> Signed-off-by: NIlya Dryomov <idryomov@gmail.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc由 Linus Torvalds 提交于
Pull char/misc driver fixes from Greg KH: "Here are some small driver fixes for 5.7-rc5 that resolve a number of minor reported issues: - mhi bus driver fixes found as people actually use the code - phy driver fixes and compat string additions - most driver fix due to link order changing when the core moved out of staging - mei driver fix - interconnect build warning fix All of these have been in linux-next for a while with no reported issues" * tag 'char-misc-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: bus: mhi: core: Fix channel device name conflict bus: mhi: core: Fix typo in comment bus: mhi: core: Offload register accesses to the controller bus: mhi: core: Remove link_status() callback bus: mhi: core: Make sure to powerdown if mhi_sync_power_up fails bus: mhi: Fix parsing of mhi_flags mei: me: disable mei interface on LBG servers. phy: qualcomm: usb-hs-28nm: Prepare clocks in init MAINTAINERS: Add Vinod Koul as Generic PHY co-maintainer interconnect: qcom: Move the static keyword to the front of declaration most: core: use function subsys_initcall() bus: mhi: core: Fix a NULL vs IS_ERR check in mhi_create_devices() phy: qcom-qusb2: Re add "qcom,sdm845-qusb2-phy" compat string phy: tegra: Select USB_COMMON for usb_get_maximum_speed()
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core由 Linus Torvalds 提交于
Pull driver core fixes from Greg KH: "Here are a number of small driver core fixes for 5.7-rc5 to resolve a bunch of reported issues with the current tree. Biggest here are the reverts and patches from John Stultz to resolve a bunch of deferred probe regressions we have been seeing in 5.7-rc right now. Along with those are some other smaller fixes: - coredump crash fix - devlink fix for when permissive mode was enabled - amba and platform device dma_parms fixes - component error silenced for when deferred probe happens All of these have been in linux-next for a while with no reported issues" * tag 'driver-core-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: regulator: Revert "Use driver_deferred_probe_timeout for regulator_init_complete_work" driver core: Ensure wait_for_device_probe() waits until the deferred_probe_timeout fires driver core: Use dev_warn() instead of dev_WARN() for deferred_probe_timeout warnings driver core: Revert default driver_deferred_probe_timeout value to 0 component: Silence bind error on -EPROBE_DEFER driver core: Fix handling of fw_devlink=permissive coredump: fix crash when umh is disabled amba: Initialize dma_parms for amba devices driver core: platform: Initialize dma_parms for platform devices
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging由 Linus Torvalds 提交于
Pull staging driver fixes from Greg KH: "Here are three small driver fixes for 5.7-rc5. Two of these are documentation fixes: - MAINTAINERS update due to removed driver - removing Wolfram from the ks7010 driver TODO file The other patch is a real fix: - fix gasket driver to proper check the return value of a call All of these have been in linux-next for a while with no reported issues" * tag 'staging-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: staging: gasket: Check the return value of gasket_get_bar_index() staging: ks7010: remove me from CC list MAINTAINERS: remove entry after hp100 driver removal
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- 08 5月, 2020 30 次提交
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty由 Linus Torvalds 提交于
Pull tty/serial fixes from Greg KH: "Here are three small TTY/Serial/VT fixes for 5.7-rc5: - revert for the bcm63xx driver "fix" that was incorrect - vt unicode console bugfix - xilinx_uartps console driver fix All of these have been in linux next with no reported issues" * tag 'tty-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: tty: xilinx_uartps: Fix missing id assignment to the console vt: fix unicode console freeing with a common interface Revert "tty: serial: bcm63xx: fix missing clk_put() in bcm63xx_uart"
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb由 Linus Torvalds 提交于
Pull USB fixes from Greg KH: "Here are some small USB fixes for 5.7-rc5 to resolve some reported issues: - syzbot found problems fixed - usbfs dma mapping fix - typec bugfixs - chipidea bugfix - usb4/thunderbolt fix - new device ids/quirks All of these have been in linux-next for a while with no reported issues" * tag 'usb-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: usb: chipidea: msm: Ensure proper controller reset using role switch API usb: typec: mux: intel: Handle alt mode HPD_HIGH usb: usbfs: correct kernel->user page attribute mismatch usb: typec: intel_pmc_mux: Fix the property names USB: core: Fix misleading driver bug report USB: serial: qcserial: Add DW5816e support USB: uas: add quirk for LaCie 2Big Quadra thunderbolt: Check return value of tb_sw_read() in usb4_switch_op() USB: serial: garmin_gps: add sanity checking for data length
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git://anongit.freedesktop.org/drm/drm由 Linus Torvalds 提交于
Pull drm fixes from Dave Airlie: "Another pretty normal week. I didn't get any i915 fixes yet, so next week I'd expect double the usual i915, but otherwise a bunch of amdgpu and some scattered other fixes. hdcp: - fix HDCP regression amdgpu: - Runtime PM fixes - DC fix for PPC - Misc DC fixes virtio: - fix context ordering issue sun4i: - old gcc warning fix ingenic-drm: - missing module support" * tag 'drm-fixes-2020-05-08' of git://anongit.freedesktop.org/drm/drm: drm/amd/display: Prevent dpcd reads with passive dongles drm/amd/display: fix counter in wait_for_no_pipes_pending drm/amd/display: Update DCN2.1 DV Code Revision drm: Fix HDCP failures when SRM fw is missing sun6i: dsi: fix gcc-4.8 drm: ingenic-drm: add MODULE_DEVICE_TABLE drm/virtio: create context before RESOURCE_CREATE_2D in 3D mode drm/amd/display: work around fp code being emitted outside of DC_FP_START/END drm/amdgpu/dc: Use WARN_ON_ONCE for ASSERT drm/amdgpu: drop redundant cg/pg ungate on runpm enter drm/amdgpu: move kfd suspend after ip_suspend_phase1
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由 Linus Torvalds 提交于
Merge misc fixes from Andrew Morton: "14 fixes and one selftest to verify the ipc fixes herein" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: mm: limit boost_watermark on small zones ubsan: disable UBSAN_ALIGNMENT under COMPILE_TEST mm/vmscan: remove unnecessary argument description of isolate_lru_pages() epoll: atomically remove wait entry on wake up kselftests: introduce new epoll60 testcase for catching lost wakeups percpu: make pcpu_alloc() aware of current gfp context mm/slub: fix incorrect interpretation of s->offset scripts/gdb: repair rb_first() and rb_last() eventpoll: fix missing wakeup for ovflist in ep_poll_callback arch/x86/kvm/svm/sev.c: change flag passed to GUP fast in sev_pin_memory() scripts/decodecode: fix trapping instruction formatting kernel/kcov.c: fix typos in kcov_remote_start documentation mm/page_alloc: fix watchdog soft lockups during set_zone_contiguous() mm, memcg: fix error return value of mem_cgroup_css_alloc() ipc/mqueue.c: change __do_notify() to bypass check_kill_permission()
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git://anongit.freedesktop.org/drm/drm-misc由 Dave Airlie 提交于
A few minor fixes for an ordering issue in virtio, an (old) gcc warning in sun4i, a probe issue in ingenic-drm and a regression in the HDCP support. Signed-off-by: NDave Airlie <airlied@redhat.com> From: Maxime Ripard <maxime@cerno.tech> Link: https://patchwork.freedesktop.org/patch/msgid/20200507160130.id64niqgf5wsha4u@gilmour.lan
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由 Dave Airlie 提交于
Merge tag 'amd-drm-fixes-5.7-2020-05-06' of git://people.freedesktop.org/~agd5f/linux into drm-fixes amd-drm-fixes-5.7-2020-05-06: amdgpu: - Runtime PM fixes - DC fix for PPC - Misc DC fixes Signed-off-by: NDave Airlie <airlied@redhat.com> From: Alex Deucher <alexdeucher@gmail.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200506212257.3893-1-alexander.deucher@amd.com
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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security由 Linus Torvalds 提交于
Pull security subsystem fix from James Morris: "Fix the default value of fs_context_parse_param hook" * 'for-v5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: security: Fix the default value of fs_context_parse_param hook
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由 Henry Willard 提交于
Commit 1c30844d ("mm: reclaim small amounts of memory when an external fragmentation event occurs") adds a boost_watermark() function which increases the min watermark in a zone by at least pageblock_nr_pages or the number of pages in a page block. On Arm64, with 64K pages and 512M huge pages, this is 8192 pages or 512M. It does this regardless of the number of managed pages managed in the zone or the likelihood of success. This can put the zone immediately under water in terms of allocating pages from the zone, and can cause a small machine to fail immediately due to OoM. Unlike set_recommended_min_free_kbytes(), which substantially increases min_free_kbytes and is tied to THP, boost_watermark() can be called even if THP is not active. The problem is most likely to appear on architectures such as Arm64 where pageblock_nr_pages is very large. It is desirable to run the kdump capture kernel in as small a space as possible to avoid wasting memory. In some architectures, such as Arm64, there are restrictions on where the capture kernel can run, and therefore, the space available. A capture kernel running in 768M can fail due to OoM immediately after boost_watermark() sets the min in zone DMA32, where most of the memory is, to 512M. It fails even though there is over 500M of free memory. With boost_watermark() suppressed, the capture kernel can run successfully in 448M. This patch limits boost_watermark() to boosting a zone's min watermark only when there are enough pages that the boost will produce positive results. In this case that is estimated to be four times as many pages as pageblock_nr_pages. Mel said: : There is no harm in marking it stable. Clearly it does not happen very : often but it's not impossible. 32-bit x86 is a lot less common now : which would previously have been vulnerable to triggering this easily. : ppc64 has a larger base page size but typically only has one zone. : arm64 is likely the most vulnerable, particularly when CMA is : configured with a small movable zone. Fixes: 1c30844d ("mm: reclaim small amounts of memory when an external fragmentation event occurs") Signed-off-by: NHenry Willard <henry.willard@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NDavid Hildenbrand <david@redhat.com> Acked-by: NMel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1588294148-6586-1-git-send-email-henry.willard@oracle.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kees Cook 提交于
The documentation for UBSAN_ALIGNMENT already mentions that it should not be used on all*config builds (and for efficient-unaligned-access architectures), so just refactor the Kconfig to correctly implement this so randconfigs will stop creating insane images that freak out objtool under CONFIG_UBSAN_TRAP (due to the false positives producing functions that never return, etc). Link: http://lkml.kernel.org/r/202005011433.C42EA3E2D@keescook Fixes: 0887a7eb ("ubsan: add trap instrumentation option") Signed-off-by: NKees Cook <keescook@chromium.org> Reported-by: NRandy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/linux-next/202004231224.D6B3B650@keescook/Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Qiwu Chen 提交于
Since commit a9e7c39f ("mm/vmscan.c: remove 7th argument of isolate_lru_pages()"), the explanation of 'mode' argument has been unnecessary. Let's remove it. Signed-off-by: NQiwu Chen <chenqiwu@xiaomi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20200501090346.2894-1-chenqiwu@xiaomi.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Roman Penyaev 提交于
This patch does two things: - fixes a lost wakeup introduced by commit 339ddb53 ("fs/epoll: remove unnecessary wakeups of nested epoll") - improves performance for events delivery. The description of the problem is the following: if N (>1) threads are waiting on ep->wq for new events and M (>1) events come, it is quite likely that >1 wakeups hit the same wait queue entry, because there is quite a big window between __add_wait_queue_exclusive() and the following __remove_wait_queue() calls in ep_poll() function. This can lead to lost wakeups, because thread, which was woken up, can handle not all the events in ->rdllist. (in better words the problem is described here: https://lkml.org/lkml/2019/10/7/905) The idea of the current patch is to use init_wait() instead of init_waitqueue_entry(). Internally init_wait() sets autoremove_wake_function as a callback, which removes the wait entry atomically (under the wq locks) from the list, thus the next coming wakeup hits the next wait entry in the wait queue, thus preventing lost wakeups. Problem is very well reproduced by the epoll60 test case [1]. Wait entry removal on wakeup has also performance benefits, because there is no need to take a ep->lock and remove wait entry from the queue after the successful wakeup. Here is the timing output of the epoll60 test case: With explicit wakeup from ep_scan_ready_list() (the state of the code prior 339ddb53): real 0m6.970s user 0m49.786s sys 0m0.113s After this patch: real 0m5.220s user 0m36.879s sys 0m0.019s The other testcase is the stress-epoll [2], where one thread consumes all the events and other threads produce many events: With explicit wakeup from ep_scan_ready_list() (the state of the code prior 339ddb53): threads events/ms run-time ms 8 5427 1474 16 6163 2596 32 6824 4689 64 7060 9064 128 6991 18309 After this patch: threads events/ms run-time ms 8 5598 1429 16 7073 2262 32 7502 4265 64 7640 8376 128 7634 16767 (number of "events/ms" represents event bandwidth, thus higher is better; number of "run-time ms" represents overall time spent doing the benchmark, thus lower is better) [1] tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c [2] https://github.com/rouming/test-tools/blob/master/stress-epoll.cSigned-off-by: NRoman Penyaev <rpenyaev@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NJason Baron <jbaron@akamai.com> Cc: Khazhismel Kumykov <khazhy@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Heiher <r@hev.cc> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200430130326.1368509-2-rpenyaev@suse.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Roman Penyaev 提交于
This test case catches lost wake up introduced by commit 339ddb53 ("fs/epoll: remove unnecessary wakeups of nested epoll") The test is simple: we have 10 threads and 10 event fds. Each thread can harvest only 1 event. 1 producer fires all 10 events at once and waits that all 10 events will be observed by 10 threads. In case of lost wakeup epoll_wait() will timeout and 0 will be returned. Test case catches two sort of problems: forgotten wakeup on event, which hits the ->ovflist list, this problem was fixed by: 5a2513239750 ("eventpoll: fix missing wakeup for ovflist in ep_poll_callback") the other problem is when several sequential events hit the same waiting thread, thus other waiters get no wakeups. Problem is fixed in the following patch. Signed-off-by: NRoman Penyaev <rpenyaev@suse.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Cc: Khazhismel Kumykov <khazhy@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Heiher <r@hev.cc> Cc: Jason Baron <jbaron@akamai.com> Link: http://lkml.kernel.org/r/20200430130326.1368509-1-rpenyaev@suse.deSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Filipe Manana 提交于
Since 5.7-rc1, on btrfs we have a percpu counter initialization for which we always pass a GFP_KERNEL gfp_t argument (this happens since commit 2992df73 ("btrfs: Implement DREW lock")). That is safe in some contextes but not on others where allowing fs reclaim could lead to a deadlock because we are either holding some btrfs lock needed for a transaction commit or holding a btrfs transaction handle open. Because of that we surround the call to the function that initializes the percpu counter with a NOFS context using memalloc_nofs_save() (this is done at btrfs_init_fs_root()). However it turns out that this is not enough to prevent a possible deadlock because percpu_alloc() determines if it is in an atomic context by looking exclusively at the gfp flags passed to it (GFP_KERNEL in this case) and it is not aware that a NOFS context is set. Because percpu_alloc() thinks it is in a non atomic context it locks the pcpu_alloc_mutex. This can result in a btrfs deadlock when pcpu_balance_workfn() is running, has acquired that mutex and is waiting for reclaim, while the btrfs task that called percpu_counter_init() (and therefore percpu_alloc()) is holding either the btrfs commit_root semaphore or a transaction handle (done fs/btrfs/backref.c: iterate_extent_inodes()), which prevents reclaim from finishing as an attempt to commit the current btrfs transaction will deadlock. Lockdep reports this issue with the following trace: ====================================================== WARNING: possible circular locking dependency detected 5.6.0-rc7-btrfs-next-77 #1 Not tainted ------------------------------------------------------ kswapd0/91 is trying to acquire lock: ffff8938a3b3fdc8 (&delayed_node->mutex){+.+.}, at: __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs] but task is already holding lock: ffffffffb4f0dbc0 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (fs_reclaim){+.+.}: fs_reclaim_acquire.part.0+0x25/0x30 __kmalloc+0x5f/0x3a0 pcpu_create_chunk+0x19/0x230 pcpu_balance_workfn+0x56a/0x680 process_one_work+0x235/0x5f0 worker_thread+0x50/0x3b0 kthread+0x120/0x140 ret_from_fork+0x3a/0x50 -> #3 (pcpu_alloc_mutex){+.+.}: __mutex_lock+0xa9/0xaf0 pcpu_alloc+0x480/0x7c0 __percpu_counter_init+0x50/0xd0 btrfs_drew_lock_init+0x22/0x70 [btrfs] btrfs_get_fs_root+0x29c/0x5c0 [btrfs] resolve_indirect_refs+0x120/0xa30 [btrfs] find_parent_nodes+0x50b/0xf30 [btrfs] btrfs_find_all_leafs+0x60/0xb0 [btrfs] iterate_extent_inodes+0x139/0x2f0 [btrfs] iterate_inodes_from_logical+0xa1/0xe0 [btrfs] btrfs_ioctl_logical_to_ino+0xb4/0x190 [btrfs] btrfs_ioctl+0x165a/0x3130 [btrfs] ksys_ioctl+0x87/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x5c/0x260 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #2 (&fs_info->commit_root_sem){++++}: down_write+0x38/0x70 btrfs_cache_block_group+0x2ec/0x500 [btrfs] find_free_extent+0xc6a/0x1600 [btrfs] btrfs_reserve_extent+0x9b/0x180 [btrfs] btrfs_alloc_tree_block+0xc1/0x350 [btrfs] alloc_tree_block_no_bg_flush+0x4a/0x60 [btrfs] __btrfs_cow_block+0x122/0x5a0 [btrfs] btrfs_cow_block+0x106/0x240 [btrfs] commit_cowonly_roots+0x55/0x310 [btrfs] btrfs_commit_transaction+0x509/0xb20 [btrfs] sync_filesystem+0x74/0x90 generic_shutdown_super+0x22/0x100 kill_anon_super+0x14/0x30 btrfs_kill_super+0x12/0x20 [btrfs] deactivate_locked_super+0x31/0x70 cleanup_mnt+0x100/0x160 task_work_run+0x93/0xc0 exit_to_usermode_loop+0xf9/0x100 do_syscall_64+0x20d/0x260 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #1 (&space_info->groups_sem){++++}: down_read+0x3c/0x140 find_free_extent+0xef6/0x1600 [btrfs] btrfs_reserve_extent+0x9b/0x180 [btrfs] btrfs_alloc_tree_block+0xc1/0x350 [btrfs] alloc_tree_block_no_bg_flush+0x4a/0x60 [btrfs] __btrfs_cow_block+0x122/0x5a0 [btrfs] btrfs_cow_block+0x106/0x240 [btrfs] btrfs_search_slot+0x50c/0xd60 [btrfs] btrfs_lookup_inode+0x3a/0xc0 [btrfs] __btrfs_update_delayed_inode+0x90/0x280 [btrfs] __btrfs_commit_inode_delayed_items+0x81f/0x870 [btrfs] __btrfs_run_delayed_items+0x8e/0x180 [btrfs] btrfs_commit_transaction+0x31b/0xb20 [btrfs] iterate_supers+0x87/0xf0 ksys_sync+0x60/0xb0 __ia32_sys_sync+0xa/0x10 do_syscall_64+0x5c/0x260 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (&delayed_node->mutex){+.+.}: __lock_acquire+0xef0/0x1c80 lock_acquire+0xa2/0x1d0 __mutex_lock+0xa9/0xaf0 __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs] btrfs_evict_inode+0x40d/0x560 [btrfs] evict+0xd9/0x1c0 dispose_list+0x48/0x70 prune_icache_sb+0x54/0x80 super_cache_scan+0x124/0x1a0 do_shrink_slab+0x176/0x440 shrink_slab+0x23a/0x2c0 shrink_node+0x188/0x6e0 balance_pgdat+0x31d/0x7f0 kswapd+0x238/0x550 kthread+0x120/0x140 ret_from_fork+0x3a/0x50 other info that might help us debug this: Chain exists of: &delayed_node->mutex --> pcpu_alloc_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(pcpu_alloc_mutex); lock(fs_reclaim); lock(&delayed_node->mutex); *** DEADLOCK *** 3 locks held by kswapd0/91: #0: (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x5/0x30 #1: (shrinker_rwsem){++++}, at: shrink_slab+0x12f/0x2c0 #2: (&type->s_umount_key#43){++++}, at: trylock_super+0x16/0x50 stack backtrace: CPU: 1 PID: 91 Comm: kswapd0 Not tainted 5.6.0-rc7-btrfs-next-77 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-0-ga698c8995f-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack+0x8f/0xd0 check_noncircular+0x170/0x190 __lock_acquire+0xef0/0x1c80 lock_acquire+0xa2/0x1d0 __mutex_lock+0xa9/0xaf0 __btrfs_release_delayed_node.part.0+0x3f/0x320 [btrfs] btrfs_evict_inode+0x40d/0x560 [btrfs] evict+0xd9/0x1c0 dispose_list+0x48/0x70 prune_icache_sb+0x54/0x80 super_cache_scan+0x124/0x1a0 do_shrink_slab+0x176/0x440 shrink_slab+0x23a/0x2c0 shrink_node+0x188/0x6e0 balance_pgdat+0x31d/0x7f0 kswapd+0x238/0x550 kthread+0x120/0x140 ret_from_fork+0x3a/0x50 This could be fixed by making btrfs pass GFP_NOFS instead of GFP_KERNEL to percpu_counter_init() in contextes where it is not reclaim safe, however that type of approach is discouraged since memalloc_[nofs|noio]_save() were introduced. Therefore this change makes pcpu_alloc() look up into an existing nofs/noio context before deciding whether it is in an atomic context or not. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Acked-by: NTejun Heo <tj@kernel.org> Acked-by: NDennis Zhou <dennis@kernel.org> Cc: Tejun Heo <tj@kernel.org> Cc: Christoph Lameter <cl@linux.com> Link: http://lkml.kernel.org/r/20200430164356.15543-1-fdmanana@kernel.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Waiman Long 提交于
In a couple of places in the slub memory allocator, the code uses "s->offset" as a check to see if the free pointer is put right after the object. That check is no longer true with commit 3202fa62 ("slub: relocate freelist pointer to middle of object"). As a result, echoing "1" into the validate sysfs file, e.g. of dentry, may cause a bunch of "Freepointer corrupt" error reports like the following to appear with the system in panic afterwards. ============================================================================= BUG dentry(666:pmcd.service) (Tainted: G B): Freepointer corrupt ----------------------------------------------------------------------------- To fix it, use the check "s->offset == s->inuse" in the new helper function freeptr_outside_object() instead. Also add another helper function get_info_end() to return the end of info block (inuse + free pointer if not overlapping with object). Fixes: 3202fa62 ("slub: relocate freelist pointer to middle of object") Signed-off-by: NWaiman Long <longman@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NMatthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: NKees Cook <keescook@chromium.org> Acked-by: NRafael Aquini <aquini@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: Vitaly Nikolenko <vnik@duasynt.com> Cc: Silvio Cesare <silvio.cesare@gmail.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Markus Elfring <Markus.Elfring@web.de> Cc: Changbin Du <changbin.du@gmail.com> Link: http://lkml.kernel.org/r/20200429135328.26976-1-longman@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Aymeric Agon-Rambosson 提交于
The current implementations of the rb_first() and rb_last() gdb functions have a variable that references itself in its instanciation, which causes the function to throw an error if a specific condition on the argument is met. The original author rather intended to reference the argument and made a typo. Referring the argument instead makes the function work as intended. Signed-off-by: NAymeric Agon-Rambosson <aymeric.agon@yandex.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NStephen Boyd <swboyd@chromium.org> Cc: Jan Kiszka <jan.kiszka@siemens.com> Cc: Kieran Bingham <kbingham@kernel.org> Cc: Douglas Anderson <dianders@chromium.org> Cc: Nikolay Borisov <n.borisov.lkml@gmail.com> Cc: Jackie Liu <liuyun01@kylinos.cn> Cc: Jason Wessel <jason.wessel@windriver.com> Link: http://lkml.kernel.org/r/20200427051029.354840-1-aymeric.agon@yandex.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Khazhismel Kumykov 提交于
In the event that we add to ovflist, before commit 339ddb53 ("fs/epoll: remove unnecessary wakeups of nested epoll") we would be woken up by ep_scan_ready_list, and did no wakeup in ep_poll_callback. With that wakeup removed, if we add to ovflist here, we may never wake up. Rather than adding back the ep_scan_ready_list wakeup - which was resulting in unnecessary wakeups, trigger a wake-up in ep_poll_callback. We noticed that one of our workloads was missing wakeups starting with 339ddb53 and upon manual inspection, this wakeup seemed missing to me. With this patch added, we no longer see missing wakeups. I haven't yet tried to make a small reproducer, but the existing kselftests in filesystem/epoll passed for me with this patch. [khazhy@google.com: use if/elif instead of goto + cleanup suggested by Roman] Link: http://lkml.kernel.org/r/20200424190039.192373-1-khazhy@google.com Fixes: 339ddb53 ("fs/epoll: remove unnecessary wakeups of nested epoll") Signed-off-by: NKhazhismel Kumykov <khazhy@google.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NRoman Penyaev <rpenyaev@suse.de> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Roman Penyaev <rpenyaev@suse.de> Cc: Heiher <r@hev.cc> Cc: Jason Baron <jbaron@akamai.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200424025057.118641-1-khazhy@google.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Janakarajan Natarajan 提交于
When trying to lock read-only pages, sev_pin_memory() fails because FOLL_WRITE is used as the flag for get_user_pages_fast(). Commit 73b0140b ("mm/gup: change GUP fast to use flags rather than a write 'bool'") updated the get_user_pages_fast() call sites to use flags, but incorrectly updated the call in sev_pin_memory(). As the original coding of this call was correct, revert the change made by that commit. Fixes: 73b0140b ("mm/gup: change GUP fast to use flags rather than a write 'bool'") Signed-off-by: NJanakarajan Natarajan <Janakarajan.Natarajan@amd.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NIra Weiny <ira.weiny@intel.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Wanpeng Li <wanpengli@tencent.com> Cc: Jim Mattson <jmattson@google.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H . Peter Anvin" <hpa@zytor.com> Cc: Mike Marshall <hubcap@omnibond.com> Cc: Brijesh Singh <brijesh.singh@amd.com> Link: http://lkml.kernel.org/r/20200423152419.87202-1-Janakarajan.Natarajan@amd.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Ivan Delalande 提交于
If the trapping instruction contains a ':', for a memory access through segment registers for example, the sed substitution will insert the '*' marker in the middle of the instruction instead of the line address: 2b: 65 48 0f c7 0f cmpxchg16b %gs:*(%rdi) <-- trapping instruction I started to think I had forgotten some quirk of the assembly syntax before noticing that it was actually coming from the script. Fix it to add the address marker at the right place for these instructions: 28: 49 8b 06 mov (%r14),%rax 2b:* 65 48 0f c7 0f cmpxchg16b %gs:(%rdi) <-- trapping instruction 30: 0f 94 c0 sete %al Fixes: 18ff44b1 ("scripts/decodecode: make faulting insn ptr more robust") Signed-off-by: NIvan Delalande <colona@arista.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NBorislav Petkov <bp@suse.de> Link: http://lkml.kernel.org/r/20200419223653.GA31248@visorSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Maciej Grochowski 提交于
Signed-off-by: NMaciej Grochowski <maciej.grochowski@pm.me> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NAndrey Konovalov <andreyknvl@google.com> Link: http://lkml.kernel.org/r/20200420030259.31674-1-maciek.grochowski@gmail.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 David Hildenbrand 提交于
Without CONFIG_PREEMPT, it can happen that we get soft lockups detected, e.g., while booting up. watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:1] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.6.0-next-20200331+ #4 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: __pageblock_pfn_to_page+0x134/0x1c0 Call Trace: set_zone_contiguous+0x56/0x70 page_alloc_init_late+0x166/0x176 kernel_init_freeable+0xfa/0x255 kernel_init+0xa/0x106 ret_from_fork+0x35/0x40 The issue becomes visible when having a lot of memory (e.g., 4TB) assigned to a single NUMA node - a system that can easily be created using QEMU. Inside VMs on a hypervisor with quite some memory overcommit, this is fairly easy to trigger. Signed-off-by: NDavid Hildenbrand <david@redhat.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NPavel Tatashin <pasha.tatashin@soleen.com> Reviewed-by: NPankaj Gupta <pankaj.gupta.linux@gmail.com> Reviewed-by: NBaoquan He <bhe@redhat.com> Reviewed-by: NShile Zhang <shile.zhang@linux.alibaba.com> Acked-by: NMichal Hocko <mhocko@suse.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Shile Zhang <shile.zhang@linux.alibaba.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Daniel Jordan <daniel.m.jordan@oracle.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Alexander Duyck <alexander.duyck@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200416073417.5003-1-david@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Yafang Shao 提交于
When I run my memcg testcase which creates lots of memcgs, I found there're unexpected out of memory logs while there're still enough available free memory. The error log is mkdir: cannot create directory 'foo.65533': Cannot allocate memory The reason is when we try to create more than MEM_CGROUP_ID_MAX memcgs, an -ENOMEM errno will be set by mem_cgroup_css_alloc(), but the right errno should be -ENOSPC "No space left on device", which is an appropriate errno for userspace's failed mkdir. As the errno really misled me, we should make it right. After this patch, the error log will be mkdir: cannot create directory 'foo.65533': No space left on device [akpm@linux-foundation.org: s/EBUSY/ENOSPC/, per Michal] [akpm@linux-foundation.org: s/EBUSY/ENOSPC/, per Michal] Fixes: 73f576c0 ("mm: memcontrol: fix cgroup creation failure after many small jobs") Suggested-by: NMatthew Wilcox <willy@infradead.org> Signed-off-by: NYafang Shao <laoar.shao@gmail.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Acked-by: NMichal Hocko <mhocko@kernel.org> Acked-by: NJohannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Link: http://lkml.kernel.org/r/20200407063621.GA18914@dhcp22.suse.cz Link: http://lkml.kernel.org/r/1586192163-20099-1-git-send-email-laoar.shao@gmail.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Oleg Nesterov 提交于
Commit cc731525 ("signal: Remove kernel interal si_code magic") changed the value of SI_FROMUSER(SI_MESGQ), this means that mq_notify() no longer works if the sender doesn't have rights to send a signal. Change __do_notify() to use do_send_sig_info() instead of kill_pid_info() to avoid check_kill_permission(). This needs the additional notify.sigev_signo != 0 check, shouldn't we change do_mq_notify() to deny sigev_signo == 0 ? Test-case: #include <signal.h> #include <mqueue.h> #include <unistd.h> #include <sys/wait.h> #include <assert.h> static int notified; static void sigh(int sig) { notified = 1; } int main(void) { signal(SIGIO, sigh); int fd = mq_open("/mq", O_RDWR|O_CREAT, 0666, NULL); assert(fd >= 0); struct sigevent se = { .sigev_notify = SIGEV_SIGNAL, .sigev_signo = SIGIO, }; assert(mq_notify(fd, &se) == 0); if (!fork()) { assert(setuid(1) == 0); mq_send(fd, "",1,0); return 0; } wait(NULL); mq_unlink("/mq"); assert(notified); return 0; } [manfred@colorfullife.com: 1) Add self_exec_id evaluation so that the implementation matches do_notify_parent 2) use PIDTYPE_TGID everywhere] Fixes: cc731525 ("signal: Remove kernel interal si_code magic") Reported-by: NYoji <yoji.fujihar.min@gmail.com> Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NManfred Spraul <manfred@colorfullife.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Markus Elfring <elfring@users.sourceforge.net> Cc: <1vier1@web.de> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/e2a782e4-eab9-4f5c-c749-c07a8f7a4e66@colorfullife.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace由 Linus Torvalds 提交于
Pull tracing fixes from Steven Rostedt: - Fix bootconfig causing kernels to fail with CONFIG_BLK_DEV_RAM enabled - Fix allocation leaks in bootconfig tool - Fix a double initialization of a variable - Fix API bootconfig usage from kprobe boot time events - Reject NULL location for kprobes - Fix crash caused by preempt delay module not cleaning up kthread correctly - Add vmalloc_sync_mappings() to prevent x86_64 page faults from recursively faulting from tracing page faults - Fix comment in gpu/trace kerneldoc header - Fix documentation of how to create a trace event class - Make the local tracing_snapshot_instance_cond() function static * tag 'trace-v5.7-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tools/bootconfig: Fix resource leak in apply_xbc() tracing: Make tracing_snapshot_instance_cond() static tracing: Fix doc mistakes in trace sample gpu/trace: Minor comment updates for gpu_mem_total tracepoint tracing: Add a vmalloc_sync_mappings() for safe measure tracing: Wait for preempt irq delay thread to finish tracing/kprobes: Reject new event if loc is NULL tracing/boottime: Fix kprobe event API usage tracing/kprobes: Fix a double initialization typo bootconfig: Fix to remove bootconfig data from initrd while boot
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由 Linus Torvalds 提交于
Merge tag 'linux-kselftest-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest Pull kselftest fixes from Shuah Khan: "ftrace test fixes and a fix to kvm Makefile for relocatable native/cross builds and installs" * tag 'linux-kselftest-5.7-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: selftests: fix kvm relocatable native/cross builds and installs selftests/ftrace: Make XFAIL green color ftrace/selftest: make unresolved cases cause failure if --fail-unresolved set ftrace/selftests: workaround cgroup RT scheduling issues
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由 Jens Axboe 提交于
We currently make some guesses as when to open this fd, but in reality we have no business (or need) to do so at all. In fact, it makes certain things fail, like O_PATH. Remove the fd lookup from these opcodes, we're just passing the 'fd' to generic helpers anyway. With that, we can also remove the special casing of fd values in io_req_needs_file(), and the 'fd_non_neg' check that we have. And we can ensure that we only read sqe->fd once. This fixes O_PATH usage with openat/openat2, and ditto statx path side oddities. Cc: stable@vger.kernel.org: # v5.6 Reported-by: NMax Kellermann <mk@cm4all.com> Signed-off-by: NJens Axboe <axboe@kernel.dk>
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由 Yunfeng Ye 提交于
Fix the @data and @fd allocations that are leaked in the error path of apply_xbc(). Link: http://lkml.kernel.org/r/583a49c9-c27a-931d-e6c2-6f63a4b18bea@huawei.comAcked-by: NMasami Hiramatsu <mhiramat@kernel.org> Signed-off-by: NYunfeng Ye <yeyunfeng@huawei.com> Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
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由 Zou Wei 提交于
Fix the following sparse warning: kernel/trace/trace.c:950:6: warning: symbol 'tracing_snapshot_instance_cond' was not declared. Should it be static? Link: http://lkml.kernel.org/r/1587614905-48692-1-git-send-email-zou_wei@huawei.comReported-by: NHulk Robot <hulkci@huawei.com> Signed-off-by: NZou Wei <zou_wei@huawei.com> Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
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由 Wei Yang 提交于
As the example below shows, DECLARE_EVENT_CLASS() is used instead of DEFINE_EVENT_CLASS(). Link: http://lkml.kernel.org/r/20200428214959.11259-1-richard.weiyang@gmail.comSigned-off-by: NWei Yang <richard.weiyang@gmail.com> Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
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由 Yiwei Zhang 提交于
This change updates the improper comment for the 'size' attribute in the tracepoint definition. Most gfx drivers pre-fault in physical pages instead of making virtual allocations. So we drop the 'Virtual' keyword here and leave this to the implementations. Link: http://lkml.kernel.org/r/20200428220825.169606-1-zzyiwei@google.comSigned-off-by: NYiwei Zhang <zzyiwei@google.com> Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
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由 Steven Rostedt (VMware) 提交于
x86_64 lazily maps in the vmalloc pages, and the way this works with per_cpu areas can be complex, to say the least. Mappings may happen at boot up, and if nothing synchronizes the page tables, those page mappings may not be synced till they are used. This causes issues for anything that might touch one of those mappings in the path of the page fault handler. When one of those unmapped mappings is touched in the page fault handler, it will cause another page fault, which in turn will cause a page fault, and leave us in a loop of page faults. Commit 763802b5 ("x86/mm: split vmalloc_sync_all()") split vmalloc_sync_all() into vmalloc_sync_unmappings() and vmalloc_sync_mappings(), as on system exit, it did not need to do a full sync on x86_64 (although it still needed to be done on x86_32). By chance, the vmalloc_sync_all() would synchronize the page mappings done at boot up and prevent the per cpu area from being a problem for tracing in the page fault handler. But when that synchronization in the exit of a task became a nop, it caused the problem to appear. Link: https://lore.kernel.org/r/20200429054857.66e8e333@oasis.local.home Cc: stable@vger.kernel.org Fixes: 737223fb ("tracing: Consolidate buffer allocation code") Reported-by: N"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com> Suggested-by: NJoerg Roedel <jroedel@suse.de> Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
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