- 15 Feb, 2019 3 commits
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Miguel Ojeda authored
The upcoming GCC 9 release extends the -Wmissing-attributes warnings (enabled by -Wall) to C and aliases: it warns when particular function attributes are missing in the aliases but not in their target. In particular, it triggers for all the init/cleanup_module aliases in the kernel (defined by the module_init/exit macros), ending up being very noisy. These aliases point to the __init/__exit functions of a module, which are defined as __cold (among other attributes). However, the aliases themselves do not have the __cold attribute. Since the compiler behaves differently when compiling a __cold function as well as when compiling paths leading to calls to __cold functions, the warning is trying to point out the possibly-forgotten attribute in the alias. In order to keep the warning enabled, we decided to silence this case. Ideally, we would mark the aliases directly as __init/__exit. However, there are currently around 132 modules in the kernel which are missing __init/__exit in their init/cleanup functions (either because they are missing, or for other reasons, e.g. the functions being called from somewhere else); and a section mismatch is a hard error. A conservative alternative was to mark the aliases as __cold only. However, since we would like to eventually enforce __init/__exit to be always marked, we chose to use the new __copy function attribute (introduced by GCC 9 as well to deal with this). With it, we copy the attributes used by the target functions into the aliases. This way, functions that were not marked as __init/__exit won't have their aliases marked either, and therefore there won't be a section mismatch. Note that the warning would go away marking either the extern declaration, the definition, or both. However, we only mark the definition of the alias, since we do not want callers (which only see the declaration) to be compiled as if the function was __cold (and therefore the paths leading to those calls would be assumed to be unlikely). Link: https://lore.kernel.org/lkml/20190123173707.GA16603@gmail.com/ Link: https://lore.kernel.org/lkml/20190206175627.GA20399@gmail.com/Suggested-by: Martin Sebor <msebor@gcc.gnu.org> Acked-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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Miguel Ojeda authored
From the GCC manual: copy copy(function) The copy attribute applies the set of attributes with which function has been declared to the declaration of the function to which the attribute is applied. The attribute is designed for libraries that define aliases or function resolvers that are expected to specify the same set of attributes as their targets. The copy attribute can be used with functions, variables, or types. However, the kind of symbol to which the attribute is applied (either function or variable) must match the kind of symbol to which the argument refers. The copy attribute copies only syntactic and semantic attributes but not attributes that affect a symbol’s linkage or visibility such as alias, visibility, or weak. The deprecated attribute is also not copied. https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html The upcoming GCC 9 release extends the -Wmissing-attributes warnings (enabled by -Wall) to C and aliases: it warns when particular function attributes are missing in the aliases but not in their target, e.g.: void __cold f(void) {} void __alias("f") g(void); diagnoses: warning: 'g' specifies less restrictive attribute than its target 'f': 'cold' [-Wmissing-attributes] Using __copy(f) we can copy the __cold attribute from f to g: void __cold f(void) {} void __copy(f) __alias("f") g(void); This attribute is most useful to deal with situations where an alias is declared but we don't know the exact attributes the target has. For instance, in the kernel, the widely used module_init/exit macros define the init/cleanup_module aliases, but those cannot be marked always as __init/__exit since some modules do not have their functions marked as such. Suggested-by: Martin Sebor <msebor@gcc.gnu.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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Miguel Ojeda authored
The upcoming GCC 9 release extends the -Wmissing-attributes warnings (enabled by -Wall) to C and aliases: it warns when particular function attributes are missing in the aliases but not in their target. In particular, it triggers here because crc32_le_base/__crc32c_le_base aren't __pure while their target crc32_le/__crc32c_le are. These aliases are used by architectures as a fallback in accelerated versions of CRC32. See commit 9784d82d ("lib/crc32: make core crc32() routines weak so they can be overridden"). Therefore, being fallbacks, it is likely that even if the aliases were called from C, there wouldn't be any optimizations possible. Currently, the only user is arm64, which calls this from asm. Still, marking the aliases as __pure makes sense and is a good idea for documentation purposes and possible future optimizations, which also silences the warning. Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
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- 03 Feb, 2019 6 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Thomas Gleixner: "A few updates for x86: - Fix an unintended sign extension issue in the fault handling code - Rename the new resource control config switch so it's less confusing - Avoid setting up EFI info in kexec when the EFI runtime is disabled. - Fix the microcode version check in the AMD microcode loader so it only loads higher version numbers and never downgrades - Set EFER.LME in the 32bit trampoline before returning to long mode to handle older AMD/KVM behaviour properly. - Add Darren and Andy as x86/platform reviewers" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/resctrl: Avoid confusion over the new X86_RESCTRL config x86/kexec: Don't setup EFI info if EFI runtime is not enabled x86/microcode/amd: Don't falsely trick the late loading mechanism MAINTAINERS: Add Andy and Darren as arch/x86/platform/ reviewers x86/fault: Fix sign-extend unintended sign extension x86/boot/compressed/64: Set EFER.LME=1 in 32-bit trampoline before returning to long mode x86/cpu: Add Atom Tremont (Jacobsville)
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull cpu hotplug fixes from Thomas Gleixner: "Two fixes for the cpu hotplug machinery: - Replace the overly clever 'SMT disabled by BIOS' detection logic as it breaks KVM scenarios and prevents speculation control updates when the Hyperthreads are brought online late after boot. - Remove a redundant invocation of the speculation control update function" * 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: cpu/hotplug: Fix "SMT disabled by BIOS" detection for KVM x86/speculation: Remove redundant arch_smt_update() invocation
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull perf fixes from Thomas Gleixner: "A pile of perf updates: - Fix broken sanity check in the /proc/sys/kernel/perf_cpu_time_max_percent write handler - Cure a perf script crash which caused by an unitinialized data structure - Highlight the hottest instruction in perf top and not a random one - Cure yet another clang issue when building perf python - Handle topology entries with no CPU correctly in the tools - Handle perf data which contains both tracepoints and performance counter entries correctly. - Add a missing NULL pointer check in perf ordered_events_free()" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf script: Fix crash when processing recorded stat data perf top: Fix wrong hottest instruction highlighted perf tools: Handle TOPOLOGY headers with no CPU perf python: Remove -fstack-clash-protection when building with some clang versions perf core: Fix perf_proc_update_handler() bug perf script: Fix crash with printing mixed trace point and other events perf ordered_events: Fix crash in ordered_events__free
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull EFI fix from Thomas Gleixner: "The dump info for the efi page table debugging lacks a terminator which causes the kernel to crash when the debugfile is read" * 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: efi/arm64: Fix debugfs crash by adding a terminator for ptdump marker
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git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linuxLinus Torvalds authored
Pull btrfs fixes from David Sterba: - regression fix: transaction commit can run away due to delayed ref waiting heuristic, this is not necessary now because of the proper reservation mechanism introduced in 5.0 - regression fix: potential crash due to use-before-check of an ERR_PTR return value - fix for transaction abort during transaction commit that needs to properly clean up pending block groups - fix deadlock during b-tree node/leaf splitting, when this happens on some of the fundamental trees, we must prevent new tree block allocation to re-enter indirectly via the block group flushing path - potential memory leak after errors during mount * tag 'for-5.0-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: On error always free subvol_name in btrfs_mount btrfs: clean up pending block groups when transaction commit aborts btrfs: fix potential oops in device_list_add btrfs: don't end the transaction for delayed refs in throttle Btrfs: fix deadlock when allocating tree block during leaf/node split
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- 02 Feb, 2019 11 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/robh/linuxLinus Torvalds authored
Pull Devicetree fix from Rob Herring: "A single fix for building DT bindings in-tree" * tag 'devicetree-fixes-for-5.0-3' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: dt-bindings: Fix dt_binding_check target for in tree builds
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Linus Torvalds authored
Merge tag 'riscv-for-linus-5.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux Pull RISC-V fixes from Palmer Dabbelt: "This contains a handful of mostly-independent patches: - make our port respect TIF_NEED_RESCHED, which fixes CONFIG_PREEMPT=y kernels - fix double-put of OF nodes - fix a misspelling of target in our Kconfig - generic PCIe is enabled in our defconfig - fix our SBI early console to properly handle line endings - fix max_low_pfn being counted in PFNs - a change to TASK_UNMAPPED_BASE to match what other arches do This has passed my standard 'boot Fedora' flow" * tag 'riscv-for-linus-5.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/palmer/riscv-linux: riscv: Adjust mmap base address at a third of task size riscv: fixup max_low_pfn with PFN_DOWN. tty/serial: use uart_console_write in the RISC-V SBL early console RISC-V: defconfig: Add CRYPTO_DEV_VIRTIO=y RISC-V: defconfig: Enable Generic PCIE by default RISC-V: defconfig: Move CONFIG_PCI{,E_XILINX} RISC-V: Kconfig: fix spelling mistake "traget" -> "target" RISC-V: asm/page.h: fix spelling mistake "CONFIG_64BITS" -> "CONFIG_64BIT" RISC-V: fix bad use of of_node_put RISC-V: Add _TIF_NEED_RESCHED check for kernel thread when CONFIG_PREEMPT=y
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git://git.kernel.dk/linux-blockLinus Torvalds authored
Pull block fixes from Jens Axboe: "A few fixes that should go into this release. This contains: - MD pull request from Song, fixing a recovery OOM issue (Alexei) - Fix for a sync related stall (Jianchao) - Dummy callback for timeouts (Tetsuo) - IDE atapi sense ordering fix (me)" * tag 'for-linus-20190202' of git://git.kernel.dk/linux-block: ide: ensure atapi sense request aren't preempted blk-mq: fix a hung issue when fsync block: pass no-op callback to INIT_WORK(). md/raid5: fix 'out of memory' during raid cache recovery
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git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds authored
Pull SCSI fixes from James Bottomley: "Five minor bug fixes. The libfc one is a tiny memory leak, the zfcp one is an incorrect user visible parameter and the rest are on error legs or obscure features" * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: scsi: 53c700: pass correct "dev" to dma_alloc_attrs() scsi: bnx2fc: Fix error handling in probe() scsi: scsi_debug: fix write_same with virtual_gb problem scsi: libfc: free skb when receiving invalid flogi resp scsi: zfcp: fix sysfs block queue limit output for max_segment_size
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Linus Torvalds authored
Merge misc fixes from Andrew Morton: "24 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (24 commits) autofs: fix error return in autofs_fill_super() autofs: drop dentry reference only when it is never used fs/drop_caches.c: avoid softlockups in drop_pagecache_sb() mm: migrate: don't rely on __PageMovable() of newpage after unlocking it psi: clarify the Kconfig text for the default-disable option mm, memory_hotplug: __offline_pages fix wrong locking mm: hwpoison: use do_send_sig_info() instead of force_sig() kasan: mark file common so ftrace doesn't trace it init/Kconfig: fix grammar by moving a closing parenthesis lib/test_kmod.c: potential double free in error handling mm, oom: fix use-after-free in oom_kill_process mm/hotplug: invalid PFNs from pfn_to_online_page() mm,memory_hotplug: fix scan_movable_pages() for gigantic hugepages psi: fix aggregation idle shut-off mm, memory_hotplug: test_pages_in_a_zone do not pass the end of zone mm, memory_hotplug: is_mem_section_removable do not pass the end of a zone oom, oom_reaper: do not enqueue same task twice mm: migrate: make buffer_migrate_page_norefs() actually succeed kernel/exit.c: release ptraced tasks before zap_pid_ns_processes x86_64: increase stack size for KASAN_EXTRA ...
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Qian Cai authored
When reading 'efi_page_tables' debugfs triggers an out-of-bounds access here: arch/arm64/mm/dump.c: 282 if (addr >= st->marker[1].start_address) { called from: arch/arm64/mm/dump.c: 331 note_page(st, addr, 2, pud_val(pud)); because st->marker++ is is called after "UEFI runtime end" which is the last element in addr_marker[]. Therefore, add a terminator like the one for kernel_page_tables, so it can be skipped to print out non-existent markers. Here's the KASAN bug report: # cat /sys/kernel/debug/efi_page_tables ---[ UEFI runtime start ]--- 0x0000000020000000-0x0000000020010000 64K PTE RW NX SHD AF ... 0x0000000020200000-0x0000000021340000 17664K PTE RW NX SHD AF ... ... 0x0000000021920000-0x0000000021950000 192K PTE RW x SHD AF ... 0x0000000021950000-0x00000000219a0000 320K PTE RW NX SHD AF ... ---[ UEFI runtime end ]--- ---[ (null) ]--- ---[ (null) ]--- BUG: KASAN: global-out-of-bounds in note_page+0x1f0/0xac0 Read of size 8 at addr ffff2000123f2ac0 by task read_all/42464 Call trace: dump_backtrace+0x0/0x298 show_stack+0x24/0x30 dump_stack+0xb0/0xdc print_address_description+0x64/0x2b0 kasan_report+0x150/0x1a4 __asan_report_load8_noabort+0x30/0x3c note_page+0x1f0/0xac0 walk_pgd+0xb4/0x244 ptdump_walk_pgd+0xec/0x140 ptdump_show+0x40/0x50 seq_read+0x3f8/0xad0 full_proxy_read+0x9c/0xc0 __vfs_read+0xfc/0x4c8 vfs_read+0xec/0x208 ksys_read+0xd0/0x15c __arm64_sys_read+0x84/0x94 el0_svc_handler+0x258/0x304 el0_svc+0x8/0xc The buggy address belongs to the variable: __compound_literal.0+0x20/0x800 Memory state around the buggy address: ffff2000123f2980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff2000123f2a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fa >ffff2000123f2a80: fa fa fa fa 00 00 00 00 fa fa fa fa 00 00 00 00 ^ ffff2000123f2b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff2000123f2b80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0 [ ardb: fix up whitespace ] [ mingo: fix up some moar ] Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Fixes: 9d80448a ("efi/arm64: Add debugfs node to dump UEFI runtime page tables") Link: http://lkml.kernel.org/r/20190202095017.13799-2-ard.biesheuvel@linaro.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Johannes Weiner authored
"Resource Control" is a very broad term for this CPU feature, and a term that is also associated with containers, cgroups etc. This can easily cause confusion. Make the user prompt more specific. Match the config symbol name. [ bp: In the future, the corresponding ARM arch-specific code will be under ARM_CPU_RESCTRL and the arch-agnostic bits will be carved out under the CPU_RESCTRL umbrella symbol. ] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Babu Moger <Babu.Moger@amd.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Morse <james.morse@arm.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: linux-doc@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Pu Wen <puwen@hygon.cn> Cc: Reinette Chatre <reinette.chatre@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190130195621.GA30653@cmpxchg.org
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git://github.com/jcmvbkbc/linux-xtensaLinus Torvalds authored
Pull xtensa fixes from Max Filippov: - fix ccount_timer_shutdown for secondary CPUs - fix secondary CPU initialization - fix secondary CPU reset vector clash with double exception vector - fix present CPUs when booting with 'maxcpus' parameter - limit possible CPUs by configured NR_CPUS - issue a warning if xtensa PIC is asked to retrigger anything other than software IRQ - fix masking/unmasking of the first two IRQs on xtensa MX PIC - fix typo in Kconfig description for user space unaligned access feature - fix Kconfig warning for selecting BUILTIN_DTB * tag 'xtensa-20190201' of git://github.com/jcmvbkbc/linux-xtensa: xtensa: SMP: limit number of possible CPUs by NR_CPUS xtensa: rename BUILTIN_DTB to BUILTIN_DTB_SOURCE xtensa: Fix typo use space=>user space drivers/irqchip: xtensa-mx: fix mask and unmask drivers/irqchip: xtensa: add warning to irq_retrigger xtensa: SMP: mark each possible CPU as present xtensa: smp_lx200_defconfig: fix vectors clash xtensa: SMP: fix secondary CPU initialization xtensa: SMP: fix ccount_timer_shutdown
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git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linuxLinus Torvalds authored
Pull arm64 fixes from Will Deacon: "Although we're still debugging a few minor arm64-specific issues in mainline, I didn't want to hold this lot up in the meantime. We've got an additional KASLR fix after the previous one wasn't quite complete, a fix for a performance regression when mapping executable pages into userspace and some fixes for kprobe blacklisting. All candidates for stable. Summary: - Fix module loading when KASLR is configured but disabled at runtime - Fix accidental IPI when mapping user executable pages - Ensure hyp-stub and KVM world switch code cannot be kprobed" * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: arm64: hibernate: Clean the __hyp_text to PoC after resume arm64: hyp-stub: Forbid kprobing of the hyp-stub arm64: kprobe: Always blacklist the KVM world-switch code arm64: kaslr: ensure randomized quantities are clean also when kaslr is off arm64: Do not issue IPIs for user executable ptes
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git://git.samba.org/sfrench/cifs-2.6Linus Torvalds authored
Pull smb3 fixes from Steve French: "SMB3 fixes, some from this week's SMB3 test evemt, 5 for stable and a particularly important one for queryxattr (see xfstests 70 and 117)" * tag '5.0-rc4-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6: cifs: update internal module version number CIFS: fix use-after-free of the lease keys CIFS: Do not consider -ENODATA as stat failure for reads CIFS: Do not count -ENODATA as failure for query directory CIFS: Fix trace command logging for SMB2 reads and writes CIFS: Fix possible oops and memory leaks in async IO cifs: limit amount of data we request for xattrs to CIFSMaxBufSize cifs: fix computation for MAX_SMB2_HDR_SIZE
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Linus Torvalds authored
Merge tag 'apparmor-pr-2019-02-01' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor Pull apparmor bug fixes from John Johansen: "Two bug fixes for apparmor: - Fix aa_label_build() error handling for failed merges - Fix warning about unused function apparmor_ipv6_postroute" * tag 'apparmor-pr-2019-02-01' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor: apparmor: Fix aa_label_build() error handling for failed merges apparmor: Fix warning about unused function apparmor_ipv6_postroute
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- 01 Feb, 2019 20 commits
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Ian Kent authored
In autofs_fill_super() on error of get inode/make root dentry the return should be ENOMEM as this is the only failure case of the called functions. Link: http://lkml.kernel.org/r/154725123240.11260.796773942606871359.stgit@pluto-themaw-netSigned-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pan Bian authored
autofs_expire_run() calls dput(dentry) to drop the reference count of dentry. However, dentry is read via autofs_dentry_ino(dentry) after that. This may result in a use-free-bug. The patch drops the reference count of dentry only when it is never used. Link: http://lkml.kernel.org/r/154725122396.11260.16053424107144453867.stgit@pluto-themaw-netSigned-off-by: Pan Bian <bianpan2016@163.com> Signed-off-by: Ian Kent <raven@themaw.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Jan Kara authored
When superblock has lots of inodes without any pagecache (like is the case for /proc), drop_pagecache_sb() will iterate through all of them without dropping sb->s_inode_list_lock which can lead to softlockups (one of our customers hit this). Fix the problem by going to the slow path and doing cond_resched() in case the process needs rescheduling. Link: http://lkml.kernel.org/r/20190114085343.15011-1-jack@suse.czSigned-off-by: Jan Kara <jack@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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David Hildenbrand authored
We had a race in the old balloon compaction code before b1123ea6 ("mm: balloon: use general non-lru movable page feature") refactored it that became visible after backporting 195a8c43 ("virtio-balloon: deflate via a page list") without the refactoring. The bug existed from commit d6d86c0a ("mm/balloon_compaction: redesign ballooned pages management") till b1123ea6 ("mm: balloon: use general non-lru movable page feature"). d6d86c0a ("mm/balloon_compaction: redesign ballooned pages management") was backported to 3.12, so the broken kernels are stable kernels [3.12 - 4.7]. There was a subtle race between dropping the page lock of the newpage in __unmap_and_move() and checking for __is_movable_balloon_page(newpage). Just after dropping this page lock, virtio-balloon could go ahead and deflate the newpage, effectively dequeueing it and clearing PageBalloon, in turn making __is_movable_balloon_page(newpage) fail. This resulted in dropping the reference of the newpage via putback_lru_page(newpage) instead of put_page(newpage), leading to page->lru getting modified and a !LRU page ending up in the LRU lists. With 195a8c43 ("virtio-balloon: deflate via a page list") backported, one would suddenly get corrupted lists in release_pages_balloon(): - WARNING: CPU: 13 PID: 6586 at lib/list_debug.c:59 __list_del_entry+0xa1/0xd0 - list_del corruption. prev->next should be ffffe253961090a0, but was dead000000000100 Nowadays this race is no longer possible, but it is hidden behind very ugly handling of __ClearPageMovable() and __PageMovable(). __ClearPageMovable() will not make __PageMovable() fail, only PageMovable(). So the new check (__PageMovable(newpage)) will still hold even after newpage was dequeued by virtio-balloon. If anybody would ever change that special handling, the BUG would be introduced again. So instead, make it explicit and use the information of the original isolated page before migration. This patch can be backported fairly easy to stable kernels (in contrast to the refactoring). Link: http://lkml.kernel.org/r/20190129233217.10747-1-david@redhat.com Fixes: d6d86c0a ("mm/balloon_compaction: redesign ballooned pages management") Signed-off-by: David Hildenbrand <david@redhat.com> Reported-by: Vratislav Bendel <vbendel@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Rafael Aquini <aquini@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Jan Kara <jack@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Vratislav Bendel <vbendel@redhat.com> Cc: Rafael Aquini <aquini@redhat.com> Cc: Konstantin Khlebnikov <k.khlebnikov@samsung.com> Cc: Minchan Kim <minchan@kernel.org> Cc: <stable@vger.kernel.org> [3.12 - 4.7] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Johannes Weiner authored
The current help text caused some confusion in online forums about whether or not to default-enable or default-disable psi in vendor kernels. This is because it doesn't communicate the reason for why we made this setting configurable in the first place: that the overhead is non-zero in an artificial scheduler stress test. Since this isn't representative of real workloads, and the effect was not measurable in scheduler-heavy real world applications such as the webservers and memcache installations at Facebook, it's fair to point out that this is a pretty cautious option to select. Link: http://lkml.kernel.org/r/20190129233617.16767-1-hannes@cmpxchg.orgSigned-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Michal Hocko authored
Jan has noticed that we do double unlock on some failure paths when offlining a page range. This is indeed the case when test_pages_in_a_zone respp. start_isolate_page_range fail. This was an omission when forward porting the debugging patch from an older kernel. Fix the issue by dropping mem_hotplug_done from the failure condition and keeping the single unlock in the catch all failure path. Link: http://lkml.kernel.org/r/20190115120307.22768-1-mhocko@kernel.org Fixes: 79605093 ("mm, memory_hotplug: print reason for the offlining failure") Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Jan Kara <jack@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Jan Kara <jack@suse.cz> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-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>
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Naoya Horiguchi authored
Currently memory_failure() is racy against process's exiting, which results in kernel crash by null pointer dereference. The root cause is that memory_failure() uses force_sig() to forcibly kill asynchronous (meaning not in the current context) processes. As discussed in thread https://lkml.org/lkml/2010/6/8/236 years ago for OOM fixes, this is not a right thing to do. OOM solves this issue by using do_send_sig_info() as done in commit d2d39309 ("signal: oom_kill_task: use SEND_SIG_FORCED instead of force_sig()"), so this patch is suggesting to do the same for hwpoison. do_send_sig_info() properly accesses to siglock with lock_task_sighand(), so is free from the reported race. I confirmed that the reported bug reproduces with inserting some delay in kill_procs(), and it never reproduces with this patch. Note that memory_failure() can send another type of signal using force_sig_mceerr(), and the reported race shouldn't happen on it because force_sig_mceerr() is called only for synchronous processes (i.e. BUS_MCEERR_AR happens only when some process accesses to the corrupted memory.) Link: http://lkml.kernel.org/r/20190116093046.GA29835@hori1.linux.bs1.fc.nec.co.jpSigned-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Reported-by: Jane Chu <jane.chu@oracle.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: William Kucharski <william.kucharski@oracle.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Anders Roxell authored
When option CONFIG_KASAN is enabled toghether with ftrace, function ftrace_graph_caller() gets in to a recursion, via functions kasan_check_read() and kasan_check_write(). Breakpoint 2, ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179 179 mcount_get_pc x0 // function's pc (gdb) bt #0 ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:179 #1 0xffffff90101406c8 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:151 #2 0xffffff90106fd084 in kasan_check_write (p=0xffffffc06c170878, size=4) at ../mm/kasan/common.c:105 #3 0xffffff90104a2464 in atomic_add_return (v=<optimized out>, i=<optimized out>) at ./include/generated/atomic-instrumented.h:71 #4 atomic_inc_return (v=<optimized out>) at ./include/generated/atomic-fallback.h:284 #5 trace_graph_entry (trace=0xffffffc03f5ff380) at ../kernel/trace/trace_functions_graph.c:441 #6 0xffffff9010481774 in trace_graph_entry_watchdog (trace=<optimized out>) at ../kernel/trace/trace_selftest.c:741 #7 0xffffff90104a185c in function_graph_enter (ret=<optimized out>, func=<optimized out>, frame_pointer=18446743799894897728, retp=<optimized out>) at ../kernel/trace/trace_functions_graph.c:196 #8 0xffffff9010140628 in prepare_ftrace_return (self_addr=18446743592948977792, parent=0xffffffc03f5ff418, frame_pointer=18446743799894897728) at ../arch/arm64/kernel/ftrace.c:231 #9 0xffffff90101406f4 in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:182 Backtrace stopped: previous frame identical to this frame (corrupt stack?) (gdb) Rework so that the kasan implementation isn't traced. Link: http://lkml.kernel.org/r/20181212183447.15890-1-anders.roxell@linaro.orgSigned-off-by: Anders Roxell <anders.roxell@linaro.org> Acked-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Jonathan Neuschäfer authored
Link: http://lkml.kernel.org/r/20190129150813.15785-1-j.neuschaefer@gmx.netSigned-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Dan Carpenter authored
There is a copy and paste bug so we set "config->test_driver" to NULL twice instead of setting "config->test_fs". Smatch complains that it leads to a double free: lib/test_kmod.c:840 __kmod_config_init() warn: 'config->test_fs' double freed Link: http://lkml.kernel.org/r/20190121140011.GA14283@kadam Fixes: d9c6a72d ("kmod: add test driver to stress test the module loader") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Luis Chamberlain <mcgrof@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Shakeel Butt authored
Syzbot instance running on upstream kernel found a use-after-free bug in oom_kill_process. On further inspection it seems like the process selected to be oom-killed has exited even before reaching read_lock(&tasklist_lock) in oom_kill_process(). More specifically the tsk->usage is 1 which is due to get_task_struct() in oom_evaluate_task() and the put_task_struct within for_each_thread() frees the tsk and for_each_thread() tries to access the tsk. The easiest fix is to do get/put across the for_each_thread() on the selected task. Now the next question is should we continue with the oom-kill as the previously selected task has exited? However before adding more complexity and heuristics, let's answer why we even look at the children of oom-kill selected task? The select_bad_process() has already selected the worst process in the system/memcg. Due to race, the selected process might not be the worst at the kill time but does that matter? The userspace can use the oom_score_adj interface to prefer children to be killed before the parent. I looked at the history but it seems like this is there before git history. Link: http://lkml.kernel.org/r/20190121215850.221745-1-shakeelb@google.com Reported-by: syzbot+7fbbfa368521945f0e3d@syzkaller.appspotmail.com Fixes: 6b0c81b3 ("mm, oom: reduce dependency on tasklist_lock") Signed-off-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Qian Cai authored
On an arm64 ThunderX2 server, the first kmemleak scan would crash [1] with CONFIG_DEBUG_VM_PGFLAGS=y due to page_to_nid() found a pfn that is not directly mapped (MEMBLOCK_NOMAP). Hence, the page->flags is uninitialized. This is due to the commit 9f1eb38e ("mm, kmemleak: little optimization while scanning") starts to use pfn_to_online_page() instead of pfn_valid(). However, in the CONFIG_MEMORY_HOTPLUG=y case, pfn_to_online_page() does not call memblock_is_map_memory() while pfn_valid() does. Historically, the commit 68709f45 ("arm64: only consider memblocks with NOMAP cleared for linear mapping") causes pages marked as nomap being no long reassigned to the new zone in memmap_init_zone() by calling __init_single_page(). Since the commit 2d070eab ("mm: consider zone which is not fully populated to have holes") introduced pfn_to_online_page() and was designed to return a valid pfn only, but it is clearly broken on arm64. Therefore, let pfn_to_online_page() call pfn_valid_within(), so it can handle nomap thanks to the commit f52bb98f ("arm64: mm: always enable CONFIG_HOLES_IN_ZONE"), while it will be optimized away on architectures where have no HOLES_IN_ZONE. [1] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000006 Mem abort info: ESR = 0x96000005 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000005 CM = 0, WnR = 0 Internal error: Oops: 96000005 [#1] SMP CPU: 60 PID: 1408 Comm: kmemleak Not tainted 5.0.0-rc2+ #8 pstate: 60400009 (nZCv daif +PAN -UAO) pc : page_mapping+0x24/0x144 lr : __dump_page+0x34/0x3dc sp : ffff00003a5cfd10 x29: ffff00003a5cfd10 x28: 000000000000802f x27: 0000000000000000 x26: 0000000000277d00 x25: ffff000010791f56 x24: ffff7fe000000000 x23: ffff000010772f8b x22: ffff00001125f670 x21: ffff000011311000 x20: ffff000010772f8b x19: fffffffffffffffe x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: ffff802698b19600 x13: ffff802698b1a200 x12: ffff802698b16f00 x11: ffff802698b1a400 x10: 0000000000001400 x9 : 0000000000000001 x8 : ffff00001121a000 x7 : 0000000000000000 x6 : ffff0000102c53b8 x5 : 0000000000000000 x4 : 0000000000000003 x3 : 0000000000000100 x2 : 0000000000000000 x1 : ffff000010772f8b x0 : ffffffffffffffff Process kmemleak (pid: 1408, stack limit = 0x(____ptrval____)) Call trace: page_mapping+0x24/0x144 __dump_page+0x34/0x3dc dump_page+0x28/0x4c kmemleak_scan+0x4ac/0x680 kmemleak_scan_thread+0xb4/0xdc kthread+0x12c/0x13c ret_from_fork+0x10/0x18 Code: d503201f f9400660 36000040 d1000413 (f9400661) ---[ end trace 4d4bd7f573490c8e ]--- Kernel panic - not syncing: Fatal exception SMP: stopping secondary CPUs Kernel Offset: disabled CPU features: 0x002,20000c38 Memory Limit: none ---[ end Kernel panic - not syncing: Fatal exception ]--- Link: http://lkml.kernel.org/r/20190122132916.28360-1-cai@lca.pw Fixes: 9f1eb38e ("mm, kmemleak: little optimization while scanning") Signed-off-by: Qian Cai <cai@lca.pw> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Oscar Salvador authored
This is the same sort of error we saw in commit 17e2e7d7 ("mm, page_alloc: fix has_unmovable_pages for HugePages"). Gigantic hugepages cross several memblocks, so it can be that the page we get in scan_movable_pages() is a page-tail belonging to a 1G-hugepage. If that happens, page_hstate()->size_to_hstate() will return NULL, and we will blow up in hugepage_migration_supported(). The splat is as follows: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 #PF error: [normal kernel read fault] PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 1 PID: 1350 Comm: bash Tainted: G E 5.0.0-rc1-mm1-1-default+ #27 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.0.0-prebuilt.qemu-project.org 04/01/2014 RIP: 0010:__offline_pages+0x6ae/0x900 Call Trace: memory_subsys_offline+0x42/0x60 device_offline+0x80/0xa0 state_store+0xab/0xc0 kernfs_fop_write+0x102/0x180 __vfs_write+0x26/0x190 vfs_write+0xad/0x1b0 ksys_write+0x42/0x90 do_syscall_64+0x5b/0x180 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Modules linked in: af_packet(E) xt_tcpudp(E) ipt_REJECT(E) xt_conntrack(E) nf_conntrack(E) nf_defrag_ipv4(E) ip_set(E) nfnetlink(E) ebtable_nat(E) ebtable_broute(E) bridge(E) stp(E) llc(E) iptable_mangle(E) iptable_raw(E) iptable_security(E) ebtable_filter(E) ebtables(E) iptable_filter(E) ip_tables(E) x_tables(E) kvm_intel(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) ghash_clmulni_intel(E) bochs_drm(E) ttm(E) aesni_intel(E) drm_kms_helper(E) aes_x86_64(E) crypto_simd(E) cryptd(E) glue_helper(E) drm(E) virtio_net(E) syscopyarea(E) sysfillrect(E) net_failover(E) sysimgblt(E) pcspkr(E) failover(E) i2c_piix4(E) fb_sys_fops(E) parport_pc(E) parport(E) button(E) btrfs(E) libcrc32c(E) xor(E) zstd_decompress(E) zstd_compress(E) xxhash(E) raid6_pq(E) sd_mod(E) ata_generic(E) ata_piix(E) ahci(E) libahci(E) libata(E) crc32c_intel(E) serio_raw(E) virtio_pci(E) virtio_ring(E) virtio(E) sg(E) scsi_mod(E) autofs4(E) [akpm@linux-foundation.org: fix brace layout, per David. Reduce indentation] Link: http://lkml.kernel.org/r/20190122154407.18417-1-osalvador@suse.deSigned-off-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Johannes Weiner authored
psi has provisions to shut off the periodic aggregation worker when there is a period of no task activity - and thus no data that needs aggregating. However, while developing psi monitoring, Suren noticed that the aggregation clock currently won't stay shut off for good. Debugging this revealed a flaw in the idle design: an aggregation run will see no task activity and decide to go to sleep; shortly thereafter, the kworker thread that executed the aggregation will go idle and cause a scheduling change, during which the psi callback will kick the !pending worker again. This will ping-pong forever, and is equivalent to having no shut-off logic at all (but with more code!) Fix this by exempting aggregation workers from psi's clock waking logic when the state change is them going to sleep. To do this, tag workers with the last work function they executed, and if in psi we see a worker going to sleep after aggregating psi data, we will not reschedule the aggregation work item. What if the worker is also executing other items before or after? Any psi state times that were incurred by work items preceding the aggregation work will have been collected from the per-cpu buckets during the aggregation itself. If there are work items following the aggregation work, the worker's last_func tag will be overwritten and the aggregator will be kept alive to process this genuine new activity. If the aggregation work is the last thing the worker does, and we decide to go idle, the brief period of non-idle time incurred between the aggregation run and the kworker's dequeue will be stranded in the per-cpu buckets until the clock is woken by later activity. But that should not be a problem. The buckets can hold 4s worth of time, and future activity will wake the clock with a 2s delay, giving us 2s worth of data we can leave behind when disabling aggregation. If it takes a worker more than two seconds to go idle after it finishes its last work item, we likely have bigger problems in the system, and won't notice one sample that was averaged with a bogus per-CPU weight. Link: http://lkml.kernel.org/r/20190116193501.1910-1-hannes@cmpxchg.org Fixes: eb414681 ("psi: pressure stall information for CPU, memory, and IO") Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Mikhail Zaslonko authored
If memory end is not aligned with the sparse memory section boundary, the mapping of such a section is only partly initialized. This may lead to VM_BUG_ON due to uninitialized struct pages access from test_pages_in_a_zone() function triggered by memory_hotplug sysfs handlers. Here are the the panic examples: CONFIG_DEBUG_VM_PGFLAGS=y kernel parameter mem=2050M -------------------------- page:000003d082008000 is uninitialized and poisoned page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) Call Trace: test_pages_in_a_zone+0xde/0x160 show_valid_zones+0x5c/0x190 dev_attr_show+0x34/0x70 sysfs_kf_seq_show+0xc8/0x148 seq_read+0x204/0x480 __vfs_read+0x32/0x178 vfs_read+0x82/0x138 ksys_read+0x5a/0xb0 system_call+0xdc/0x2d8 Last Breaking-Event-Address: test_pages_in_a_zone+0xde/0x160 Kernel panic - not syncing: Fatal exception: panic_on_oops Fix this by checking whether the pfn to check is within the zone. [mhocko@suse.com: separated this change from http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com] Link: http://lkml.kernel.org/r/20190128144506.15603-3-mhocko@kernel.org [mhocko@suse.com: separated this change from http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com] Signed-off-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Michal Hocko authored
Patch series "mm, memory_hotplug: fix uninitialized pages fallouts", v2. Mikhail Zaslonko has posted fixes for the two bugs quite some time ago [1]. I have pushed back on those fixes because I believed that it is much better to plug the problem at the initialization time rather than play whack-a-mole all over the hotplug code and find all the places which expect the full memory section to be initialized. We have ended up with commit 2830bf6f ("mm, memory_hotplug: initialize struct pages for the full memory section") merged and cause a regression [2][3]. The reason is that there might be memory layouts when two NUMA nodes share the same memory section so the merged fix is simply incorrect. In order to plug this hole we really have to be zone range aware in those handlers. I have split up the original patch into two. One is unchanged (patch 2) and I took a different approach for `removable' crash. [1] http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com [2] https://bugzilla.redhat.com/show_bug.cgi?id=1666948 [3] http://lkml.kernel.org/r/20190125163938.GA20411@dhcp22.suse.cz This patch (of 2): Mikhail has reported the following VM_BUG_ON triggered when reading sysfs removable state of a memory block: page:000003d08300c000 is uninitialized and poisoned page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) Call Trace: is_mem_section_removable+0xb4/0x190 show_mem_removable+0x9a/0xd8 dev_attr_show+0x34/0x70 sysfs_kf_seq_show+0xc8/0x148 seq_read+0x204/0x480 __vfs_read+0x32/0x178 vfs_read+0x82/0x138 ksys_read+0x5a/0xb0 system_call+0xdc/0x2d8 Last Breaking-Event-Address: is_mem_section_removable+0xb4/0x190 Kernel panic - not syncing: Fatal exception: panic_on_oops The reason is that the memory block spans the zone boundary and we are stumbling over an unitialized struct page. Fix this by enforcing zone range in is_mem_section_removable so that we never run away from a zone. Link: http://lkml.kernel.org/r/20190128144506.15603-2-mhocko@kernel.orgSigned-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Debugged-by: Mikhail Zaslonko <zaslonko@linux.ibm.com> Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Tetsuo Handa authored
Arkadiusz reported that enabling memcg's group oom killing causes strange memcg statistics where there is no task in a memcg despite the number of tasks in that memcg is not 0. It turned out that there is a bug in wake_oom_reaper() which allows enqueuing same task twice which makes impossible to decrease the number of tasks in that memcg due to a refcount leak. This bug existed since the OOM reaper became invokable from task_will_free_mem(current) path in out_of_memory() in Linux 4.7, T1@P1 |T2@P1 |T3@P1 |OOM reaper ----------+----------+----------+------------ # Processing an OOM victim in a different memcg domain. try_charge() mem_cgroup_out_of_memory() mutex_lock(&oom_lock) try_charge() mem_cgroup_out_of_memory() mutex_lock(&oom_lock) try_charge() mem_cgroup_out_of_memory() mutex_lock(&oom_lock) out_of_memory() oom_kill_process(P1) do_send_sig_info(SIGKILL, @P1) mark_oom_victim(T1@P1) wake_oom_reaper(T1@P1) # T1@P1 is enqueued. mutex_unlock(&oom_lock) out_of_memory() mark_oom_victim(T2@P1) wake_oom_reaper(T2@P1) # T2@P1 is enqueued. mutex_unlock(&oom_lock) out_of_memory() mark_oom_victim(T1@P1) wake_oom_reaper(T1@P1) # T1@P1 is enqueued again due to oom_reaper_list == T2@P1 && T1@P1->oom_reaper_list == NULL. mutex_unlock(&oom_lock) # Completed processing an OOM victim in a different memcg domain. spin_lock(&oom_reaper_lock) # T1P1 is dequeued. spin_unlock(&oom_reaper_lock) but memcg's group oom killing made it easier to trigger this bug by calling wake_oom_reaper() on the same task from one out_of_memory() request. Fix this bug using an approach used by commit 855b0183 ("oom, oom_reaper: disable oom_reaper for oom_kill_allocating_task"). As a side effect of this patch, this patch also avoids enqueuing multiple threads sharing memory via task_will_free_mem(current) path. Link: http://lkml.kernel.org/r/e865a044-2c10-9858-f4ef-254bc71d6cc2@i-love.sakura.ne.jp Link: http://lkml.kernel.org/r/5ee34fc6-1485-34f8-8790-903ddabaa809@i-love.sakura.ne.jp Fixes: af8e15cc ("oom, oom_reaper: do not enqueue task if it is on the oom_reaper_list head") Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: Arkadiusz Miskiewicz <arekm@maven.pl> Tested-by: Arkadiusz Miskiewicz <arekm@maven.pl> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Roman Gushchin <guro@fb.com> Cc: Tejun Heo <tj@kernel.org> Cc: Aleksa Sarai <asarai@suse.de> Cc: Jay Kamat <jgkamat@fb.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Jan Kara authored
Currently, buffer_migrate_page_norefs() was constantly failing because buffer_migrate_lock_buffers() grabbed reference on each buffer. In fact, there's no reason for buffer_migrate_lock_buffers() to grab any buffer references as the page is locked during all our operation and thus nobody can reclaim buffers from the page. So remove grabbing of buffer references which also makes buffer_migrate_page_norefs() succeed. Link: http://lkml.kernel.org/r/20190116131217.7226-1-jack@suse.cz Fixes: 89cb0888 "mm: migrate: provide buffer_migrate_page_norefs()" Signed-off-by: Jan Kara <jack@suse.cz> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Zi Yan <zi.yan@cs.rutgers.edu> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Andrei Vagin authored
Currently, exit_ptrace() adds all ptraced tasks in a dead list, then zap_pid_ns_processes() waits on all tasks in a current pidns, and only then are tasks from the dead list released. zap_pid_ns_processes() can get stuck on waiting tasks from the dead list. In this case, we will have one unkillable process with one or more dead children. Thanks to Oleg for the advice to release tasks in find_child_reaper(). Link: http://lkml.kernel.org/r/20190110175200.12442-1-avagin@gmail.com Fixes: 7c8bd232 ("exit: ptrace: shift "reap dead" code from exit_ptrace() to forget_original_parent()") Signed-off-by: Andrei Vagin <avagin@gmail.com> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Qian Cai authored
If the kernel is configured with KASAN_EXTRA, the stack size is increasted significantly because this option sets "-fstack-reuse" to "none" in GCC [1]. As a result, it triggers stack overrun quite often with 32k stack size compiled using GCC 8. For example, this reproducer https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/madvise/madvise06.c triggers a "corrupted stack end detected inside scheduler" very reliably with CONFIG_SCHED_STACK_END_CHECK enabled. There are just too many functions that could have a large stack with KASAN_EXTRA due to large local variables that have been called over and over again without being able to reuse the stacks. Some noticiable ones are size 7648 shrink_page_list 3584 xfs_rmap_convert 3312 migrate_page_move_mapping 3312 dev_ethtool 3200 migrate_misplaced_transhuge_page 3168 copy_process There are other 49 functions are over 2k in size while compiling kernel with "-Wframe-larger-than=" even with a related minimal config on this machine. Hence, it is too much work to change Makefiles for each object to compile without "-fsanitize-address-use-after-scope" individually. [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81715#c23 Although there is a patch in GCC 9 to help the situation, GCC 9 probably won't be released in a few months and then it probably take another 6-month to 1-year for all major distros to include it as a default. Hence, the stack usage with KASAN_EXTRA can be revisited again in 2020 when GCC 9 is everywhere. Until then, this patch will help users avoid stack overrun. This has already been fixed for arm64 for the same reason via 6e883067 ("arm64: kasan: Increase stack size for KASAN_EXTRA"). Link: http://lkml.kernel.org/r/20190109215209.2903-1-cai@lca.pwSigned-off-by: Qian Cai <cai@lca.pw> 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: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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