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The SMAP and Reserved checking do not have nice comments. Add
some to clarify and make it match everything else.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160225.FFD44B8D@viggo.jf.intel.com
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The last patch broke out kernel address space handing into its own
helper. Now, do the same for user address space handling.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160223.9C4F6440@viggo.jf.intel.com
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The page fault handler (__do_page_fault()) basically has two sections:
one for handling faults in the kernel portion of the address space
and another for faults in the user portion of the address space.
But, these two parts don't stick out that well. Let's make that more
clear from code separation and naming. Pull kernel fault
handling into its own helper, and reflect that naming by renaming
spurious_fault() -> spurious_kernel_fault().
Also, rewrite the vmalloc() handling comment a bit. It was a bit
stale and also glossed over the reserved bit handling.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160222.401F4E10@viggo.jf.intel.com
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We pass around a variable called "error_code" all around the page
fault code. Sounds simple enough, especially since "error_code" looks
like it exactly matches the values that the hardware gives us on the
stack to report the page fault error code (PFEC in SDM parlance).
But, that's not how it works.
For part of the page fault handler, "error_code" does exactly match
PFEC. But, during later parts, it diverges and starts to mean
something a bit different.
Give it two names for its two jobs.
The place it diverges is also really screwy. It's only in a spot
where the hardware tells us we have kernel-mode access that occurred
while we were in usermode accessing user-controlled address space.
Add a warning in there.
Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160220.4A2272C9@viggo.jf.intel.com
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Lazy TLB mode can result in an idle CPU being woken up by a TLB flush,
when all it really needs to do is reload %CR3 at the next context switch,
assuming no page table pages got freed.
Memory ordering is used to prevent race conditions between switch_mm_irqs_off,
which checks whether .tlb_gen changed, and the TLB invalidation code, which
increments .tlb_gen whenever page table entries get invalidated.
The atomic increment in inc_mm_tlb_gen is its own barrier; the context
switch code adds an explicit barrier between reading tlbstate.is_lazy and
next->context.tlb_gen.
CPUs in lazy TLB mode remain part of the mm_cpumask(mm), both because
that allows TLB flush IPIs to be sent at page table freeing time, and
because the cache line bouncing on the mm_cpumask(mm) was responsible
for about half the CPU use in switch_mm_irqs_off().
We can change native_flush_tlb_others() without touching other
(paravirt) implementations of flush_tlb_others() because we'll be
flushing less. The existing implementations flush more and are
therefore still correct.
Cc: npiggin@gmail.com
Cc: mingo@kernel.org
Cc: will.deacon@arm.com
Cc: kernel-team@fb.com
Cc: luto@kernel.org
Cc: hpa@zytor.com
Tested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180926035844.1420-8-riel@surriel.com
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Pass the information on to native_flush_tlb_others.
No functional changes.
Cc: npiggin@gmail.com
Cc: mingo@kernel.org
Cc: will.deacon@arm.com
Cc: songliubraving@fb.com
Cc: kernel-team@fb.com
Cc: hpa@zytor.com
Cc: luto@kernel.org
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180926035844.1420-7-riel@surriel.com
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Add an argument to flush_tlb_mm_range to indicate whether page tables
are about to be freed after this TLB flush. This allows for an
optimization of flush_tlb_mm_range to skip CPUs in lazy TLB mode.
No functional changes.
Cc: npiggin@gmail.com
Cc: mingo@kernel.org
Cc: will.deacon@arm.com
Cc: songliubraving@fb.com
Cc: kernel-team@fb.com
Cc: luto@kernel.org
Cc: hpa@zytor.com
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180926035844.1420-6-riel@surriel.com
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Introduce a variant of on_each_cpu_cond that iterates only over the
CPUs in a cpumask, in order to avoid making callbacks for every single
CPU in the system when we only need to test a subset.
Cc: npiggin@gmail.com
Cc: mingo@kernel.org
Cc: will.deacon@arm.com
Cc: songliubraving@fb.com
Cc: kernel-team@fb.com
Cc: hpa@zytor.com
Cc: luto@kernel.org
Signed-off-by: Rik van Riel <riel@surriel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180926035844.1420-5-riel@surriel.com
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The code in on_each_cpu_cond sets CPUs in a locally allocated bitmask,
which should never be used by other CPUs simultaneously. There is no
need to use locked memory accesses to set the bits in this bitmap.
Switch to __cpumask_set_cpu.
Cc: npiggin@gmail.com
Cc: mingo@kernel.org
Cc: will.deacon@arm.com
Cc: songliubraving@fb.com
Cc: kernel-team@fb.com
Cc: hpa@zytor.com
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180926035844.1420-4-riel@surriel.com
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Move some code that will be needed for the lazy -> !lazy state
transition when a lazy TLB CPU has gotten out of date.
No functional changes, since the if (real_prev == next) branch
always returns.
(cherry picked from commit 61d0beb5796ab11f7f3bf38cb2eccc6579aaa70b)
Cc: npiggin@gmail.com
Cc: efault@gmx.de
Cc: will.deacon@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: songliubraving@fb.com
Cc: kernel-team@fb.com
Cc: hpa@zytor.com
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Rik van Riel <riel@surriel.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180716190337.26133-4-riel@surriel.com
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On most workloads, the number of context switches far exceeds the
number of TLB flushes sent. Optimizing the context switches, by always
using lazy TLB mode, speeds up those workloads.
This patch results in about a 1% reduction in CPU use on a two socket
Broadwell system running a memcache like workload.
Cc: npiggin@gmail.com
Cc: efault@gmx.de
Cc: will.deacon@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-team@fb.com
Cc: hpa@zytor.com
Cc: luto@kernel.org
Tested-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Rik van Riel <riel@surriel.com>
(cherry picked from commit 95b0e6357d3e4e05349668940d7ff8f3b7e7e11e)
Acked-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180716190337.26133-7-riel@surriel.com
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Use the new tlb_get_unmap_shift() to determine the stride of the
INVLPG loop.
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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Lianbo reported a build error with a particular 32-bit config, see Link
below for details.
Provide a weak copy_oldmem_page_encrypted() function which architectures
can override, in the same manner other functionality in that file is
supplied.
Reported-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
CC: x86@kernel.org
Link: http://lkml.kernel.org/r/710b9d95-2f70-eadf-c4a1-c3dc80ee4ebb@redhat.com
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After the cleanups from Baoquan He, make it even more readable:
- Remove the 'bits' area size column: it's pretty pointless and was even
wrong for some of the entries. Given that MB, GB, TB, PT are 10, 20,
30 and 40 bits, a "8 TB" size description makes it obvious that it's
43 bits.
- Introduce an "offset" column:
--------------------------------------------------------------------------------
start addr | offset | end addr | size | VM area description
-----------------|------------|------------------|---------|--------------------
...
ffff880000000000 | -120 TB | ffffc7ffffffffff | 64 TB | direct mapping of all physical memory (page_offset_base),
this is what limits max physical memory supported.
The -120 TB notation makes it obvious where this particular virtual memory
region starts: 120 TB down from the top of the 64-bit virtual memory space.
Especially the layout of the kernel mappings is a *lot* more obvious when
written this way, plus it's much easier to compare it with the size column
and understand/check/validate and modify the kernel's layout in the future.
- Mark the part from where the 47-bit and 56-bit kernel layouts are 100% identical,
this starts at the -512 GB offset and the EFI region.
- Re-shuffle the size desciptions to be continous blocks of sizes, instead of the
often mixed size. I.e. write "0.5 TB" instead of "512 GB" if we are still in
the TB-granular region of the map.
- Make the 47-bit and 56-bit descriptions use the *exact* same layout and wording,
and only differ where there's a material difference. This makes it easy to compare
the two tables side by side by switching between two terminal tabs.
- Plus enhance a lot of other stylistic/typographical details: make the tables
explicitly tabular, add headers, enhance certain entries, etc. etc.
Note that there are some apparent errors in the tables as well, but I'll fix
them in a separate patch to make it easier to review/validate.
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: corbet@lwn.net
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: thgarnie@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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In Documentation/x86/x86_64/mm.txt, the description of the x86-64 virtual
memory layout has become a confusing hodgepodge of inconsistencies:
- there's a hard to read mixture of 'TB' and 'bits' notation
- the entries sometimes mention a size in the description and sometimes not
- sometimes they list holes by address, sometimes only as an 'unused hole' line
So make it all a coherent, readable, well organized description.
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: corbet@lwn.net
Cc: linux-doc@vger.kernel.org
Cc: thgarnie@google.com
Link: http://lkml.kernel.org/r/20181006084327.27467-3-bhe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Currently CONFIG_RANDOMIZE_BASE=y is set by default, which makes some of the
old comments above the KERNEL_IMAGE_SIZE definition out of date. Update them
to the current state of affairs.
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: corbet@lwn.net
Cc: linux-doc@vger.kernel.org
Cc: thgarnie@google.com
Link: http://lkml.kernel.org/r/20181006084327.27467-2-bhe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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In the kdump kernel, the memory of the first kernel needs to be dumped
into the vmcore file.
If SME is enabled in the first kernel, the old memory has to be remapped
with the memory encryption mask in order to access it properly.
Split copy_oldmem_page() functionality to handle encrypted memory
properly.
[ bp: Heavily massage everything. ]
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: kexec@lists.infradead.org
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: akpm@linux-foundation.org
Cc: dan.j.williams@intel.com
Cc: bhelgaas@google.com
Cc: baiyaowei@cmss.chinamobile.com
Cc: tiwai@suse.de
Cc: brijesh.singh@amd.com
Cc: dyoung@redhat.com
Cc: bhe@redhat.com
Cc: jroedel@suse.de
Link: https://lkml.kernel.org/r/be7b47f9-6be6-e0d1-2c2a-9125bc74b818@redhat.com
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The kdump kernel copies the IOMMU device table from the old device table
which is encrypted when SME is enabled in the first kernel. So remap the
old device table with the memory encryption mask in the kdump kernel.
[ bp: Massage commit message. ]
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Acked-by: Joerg Roedel <jroedel@suse.de>
Cc: kexec@lists.infradead.org
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: akpm@linux-foundation.org
Cc: dan.j.williams@intel.com
Cc: bhelgaas@google.com
Cc: baiyaowei@cmss.chinamobile.com
Cc: tiwai@suse.de
Cc: brijesh.singh@amd.com
Cc: dyoung@redhat.com
Cc: bhe@redhat.com
Link: https://lkml.kernel.org/r/20180930031033.22110-4-lijiang@redhat.com
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When SME is enabled in the first kernel, it needs to allocate decrypted
pages for kdump because when the kdump kernel boots, these pages need to
be accessed decrypted in the initial boot stage, before SME is enabled.
[ bp: clean up text. ]
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: kexec@lists.infradead.org
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: akpm@linux-foundation.org
Cc: dan.j.williams@intel.com
Cc: bhelgaas@google.com
Cc: baiyaowei@cmss.chinamobile.com
Cc: tiwai@suse.de
Cc: brijesh.singh@amd.com
Cc: dyoung@redhat.com
Cc: bhe@redhat.com
Cc: jroedel@suse.de
Link: https://lkml.kernel.org/r/20180930031033.22110-3-lijiang@redhat.com
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When SME is enabled, the memory is encrypted in the first kernel. In
this case, SME also needs to be enabled in the kdump kernel, and we have
to remap the old memory with the memory encryption mask.
The case of concern here is if SME is active in the first kernel,
and it is active too in the kdump kernel. There are four cases to be
considered:
a. dump vmcore
It is encrypted in the first kernel, and needs be read out in the
kdump kernel.
b. crash notes
When dumping vmcore, the people usually need to read useful
information from notes, and the notes is also encrypted.
c. iommu device table
It's encrypted in the first kernel, kdump kernel needs to access its
content to analyze and get information it needs.
d. mmio of AMD iommu
not encrypted in both kernels
Add a new bool parameter @encrypted to __ioremap_caller(). If set,
memory will be remapped with the SME mask.
Add a new function ioremap_encrypted() to explicitly pass in a true
value for @encrypted. Use ioremap_encrypted() for the above a, b, c
cases.
[ bp: cleanup commit message, extern defs in io.h and drop forgotten
include. ]
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: kexec@lists.infradead.org
Cc: tglx@linutronix.de
Cc: mingo@redhat.com
Cc: hpa@zytor.com
Cc: akpm@linux-foundation.org
Cc: dan.j.williams@intel.com
Cc: bhelgaas@google.com
Cc: baiyaowei@cmss.chinamobile.com
Cc: tiwai@suse.de
Cc: brijesh.singh@amd.com
Cc: dyoung@redhat.com
Cc: bhe@redhat.com
Cc: jroedel@suse.de
Link: https://lkml.kernel.org/r/20180927071954.29615-2-lijiang@redhat.com
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Signed-off-by: Takuya Yamamoto <tkyymmt01@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20180829072730.988-1-tkyymmt01@gmail.com
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If we IPI for WBINDV, then we might as well kill the entire TLB too.
But if we don't have to invalidate cache, there is no reason not to
use a range TLB flush.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180919085948.195633798@infradead.org
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The start of cpa_flush_range() and cpa_flush_array() is the same, use
a common function.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180919085948.138859183@infradead.org
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Rather than guarding cpa_flush_array() users with a CLFLUSH test, put
it inside.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180919085948.087848187@infradead.org
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Rather than guarding all cpa_flush_range() uses with a CLFLUSH test,
put it inside.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180919085948.036195503@infradead.org
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Both cpa_flush_range() and cpa_flush_array() have a well specified
range, use that to do a range based TLB invalidate.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180919085947.985193217@infradead.org
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CAT has happened, WBINDV is bad (even before CAT blowing away the
entire cache on a multi-core platform wasn't nice), try not to use it
ever.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180919085947.933674526@infradead.org
|
|
There is an atom errata, where we do a local TLB invalidate right
before we return and then do a global TLB invalidate.
Move the global invalidate up a little bit and avoid the local
invalidate entirely.
This does put the global invalidate under pgd_lock, but that shouldn't
matter.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180919085947.882287392@infradead.org
|
|
Instead of open-coding it..
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180919085947.831102058@infradead.org
|
|
The extra loop which tries hard to preserve large pages in case of conflicts
with static protection regions turns out to be not preserving anything, at
least not in the experiments which have been conducted.
There might be corner cases in which the code would be able to preserve a
large page oaccsionally, but it's really not worth the extra code and the
cycles wasted in the common case.
Before:
1G pages checked: 2
1G pages sameprot: 0
1G pages preserved: 0
2M pages checked: 541
2M pages sameprot: 466
2M pages preserved: 47
4K pages checked: 514
4K pages set-checked: 7668
After:
1G pages checked: 2
1G pages sameprot: 0
1G pages preserved: 0
2M pages checked: 538
2M pages sameprot: 466
2M pages preserved: 47
4K pages set-checked: 7668
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143546.589642503@linutronix.de
|
|
To avoid excessive 4k wise checks in the common case do a quick check first
whether the requested new page protections conflict with a static
protection area in the large page. If there is no conflict then the
decision whether to preserve or to split the page can be made immediately.
If the requested range covers the full large page, preserve it. Otherwise
split it up. No point in doing a slow crawl in 4k steps.
Before:
1G pages checked: 2
1G pages sameprot: 0
1G pages preserved: 0
2M pages checked: 538
2M pages sameprot: 466
2M pages preserved: 47
4K pages checked: 560642
4K pages set-checked: 7668
After:
1G pages checked: 2
1G pages sameprot: 0
1G pages preserved: 0
2M pages checked: 541
2M pages sameprot: 466
2M pages preserved: 47
4K pages checked: 514
4K pages set-checked: 7668
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143546.507259989@linutronix.de
|
|
When the existing mapping is correct and the new requested page protections
are the same as the existing ones, then further checks can be omitted and the
large page can be preserved. The slow path 4k wise check will not come up with
a different result.
Before:
1G pages checked: 2
1G pages sameprot: 0
1G pages preserved: 0
2M pages checked: 540
2M pages sameprot: 466
2M pages preserved: 47
4K pages checked: 800709
4K pages set-checked: 7668
After:
1G pages checked: 2
1G pages sameprot: 0
1G pages preserved: 0
2M pages checked: 538
2M pages sameprot: 466
2M pages preserved: 47
4K pages checked: 560642
4K pages set-checked: 7668
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143546.424477581@linutronix.de
|
|
With the range check it is possible to do a quick verification that the
current mapping is correct vs. the static protection areas.
In case a incorrect mapping is detected a warning is emitted and the large
page is split up. If the large page is a 2M page, then the split code is
forced to check the static protections for the PTE entries to fix up the
incorrectness. For 1G pages this can't be done easily because that would
require to either find the offending 2M areas before the split or
afterwards. For now just warn about that case and revisit it when reported.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143546.331408643@linutronix.de
|
|
If the new pgprot has the PRESENT bit cleared, then conflicts vs. RW/NX are
completely irrelevant.
Before:
1G pages checked: 2
1G pages sameprot: 0
1G pages preserved: 0
2M pages checked: 540
2M pages sameprot: 466
2M pages preserved: 47
4K pages checked: 800770
4K pages set-checked: 7668
After:
1G pages checked: 2
1G pages sameprot: 0
1G pages preserved: 0
2M pages checked: 540
2M pages sameprot: 466
2M pages preserved: 47
4K pages checked: 800709
4K pages set-checked: 7668
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143546.245849757@linutronix.de
|
|
The large page preservation mechanism is just magic and provides no
information at all. Add optional statistic output in debugfs so the magic can
be evaluated. Defaults is off.
Output:
1G pages checked: 2
1G pages sameprot: 0
1G pages preserved: 0
2M pages checked: 540
2M pages sameprot: 466
2M pages preserved: 47
4K pages checked: 800770
4K pages set-checked: 7668
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143546.160867778@linutronix.de
|
|
The whole static protection magic is silently fixing up anything which is
handed in. That's just wrong. The offending call sites need to be fixed.
Add a debug mechanism which emits a warning if a requested mapping needs to be
fixed up. The DETECT debug mechanism is really not meant to be enabled except
for developers, so limit the output hard to the protection fixups.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143546.078998733@linutronix.de
|
|
Checking static protections only page by page is slow especially for huge
pages. To allow quick checks over a complete range, add the ability to do
that.
Make the checks inclusive so the ranges can be directly used for debug output
later.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143545.995734490@linutronix.de
|
|
static_protections() is pretty unreadable. Split it up into separate checks
for each protection area.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143545.913005317@linutronix.de
|
|
Avoid the extra variable and gotos by splitting the function into the
actual algorithm and a callable function which contains the lock
protection.
Rename it to should_split_large_page() while at it so the return values make
actually sense.
Clean up the code flow, comments and general whitespace damage while at it. No
functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143545.830507216@linutronix.de
|
|
The sequence of marking text and rodata read-only in 32bit init is:
set_ro(text);
kernel_set_to_readonly = 1;
set_ro(rodata);
When kernel_set_to_readonly is 1 it enables the protection mechanism in CPA
for the read only regions. With the upcoming checks for existing mappings
this consequently triggers the warning about an existing mapping being
incorrect vs. static protections because rodata has not been converted yet.
There is no technical reason to split the two, so just combine the RO
protection to convert text and rodata in one go.
Convert the printks to pr_info while at it.
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Bin Yang <bin.yang@intel.com>
Cc: Mark Gross <mark.gross@intel.com>
Link: https://lkml.kernel.org/r/20180917143545.731701535@linutronix.de
|
|
|
|
Klaus Kusche reported that the I/O busy time in /proc/diskstats was not
updating properly on 4.18. This is because we started using ktime to
track elapsed time, and we convert nanoseconds to jiffies when we update
the partition counter. However, this gets rounded down, so any I/Os that
take less than a jiffy are not accounted for. Previously in this case,
the value of jiffies would sometimes increment while we were doing I/O,
so at least some I/Os were accounted for.
Let's convert the stats to use nanoseconds internally. We still report
milliseconds as before, now more accurately than ever. The value is
still truncated to 32 bits for backwards compatibility.
Fixes: 522a777566f5 ("block: consolidate struct request timestamp fields")
Cc: stable@vger.kernel.org
Reported-by: Klaus Kusche <klaus.kusche@computerix.info>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
|
We met a kernel panic when enabling earlycon, which is due to the fixmap
address of earlycon is not statically setup.
Currently the static fixmap setup in head_64.S only covers 2M virtual
address space, while it actually could be in 4M space with different
kernel configurations, e.g. when VSYSCALL emulation is disabled.
So increase the static space to 4M for now by defining FIXMAP_PMD_NUM to 2,
and add a build time check to ensure that the fixmap is covered by the
initial static page tables.
Fixes: 1ad83c858c7d ("x86_64,vsyscall: Make vsyscall emulation configurable")
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: kernel test robot <rong.a.chen@intel.com>
Reviewed-by: Juergen Gross <jgross@suse.com> (Xen parts)
Cc: H Peter Anvin <hpa@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirsky <luto@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180920025828.23699-1-feng.tang@intel.com
|
|
While reading block, it is possible that io error return due to underlying
storage issue, in this case, BH_NeedsValidate was left in the buffer head.
Then when reading the very block next time, if it was already linked into
journal, that will trigger the following panic.
[203748.702517] kernel BUG at fs/ocfs2/buffer_head_io.c:342!
[203748.702533] invalid opcode: 0000 [#1] SMP
[203748.702561] Modules linked in: ocfs2 ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm ocfs2_nodemanager ocfs2_stackglue configfs sunrpc dm_switch dm_queue_length dm_multipath bonding be2iscsi iscsi_boot_sysfs bnx2i cnic uio cxgb4i iw_cxgb4 cxgb4 cxgb3i libcxgbi iw_cxgb3 cxgb3 mdio ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr ipv6 iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ipmi_devintf iTCO_wdt iTCO_vendor_support dcdbas ipmi_ssif i2c_core ipmi_si ipmi_msghandler acpi_pad pcspkr sb_edac edac_core lpc_ich mfd_core shpchp sg tg3 ptp pps_core ext4 jbd2 mbcache2 sr_mod cdrom sd_mod ahci libahci megaraid_sas wmi dm_mirror dm_region_hash dm_log dm_mod
[203748.703024] CPU: 7 PID: 38369 Comm: touch Not tainted 4.1.12-124.18.6.el6uek.x86_64 #2
[203748.703045] Hardware name: Dell Inc. PowerEdge R620/0PXXHP, BIOS 2.5.2 01/28/2015
[203748.703067] task: ffff880768139c00 ti: ffff88006ff48000 task.ti: ffff88006ff48000
[203748.703088] RIP: 0010:[<ffffffffa05e9f09>] [<ffffffffa05e9f09>] ocfs2_read_blocks+0x669/0x7f0 [ocfs2]
[203748.703130] RSP: 0018:ffff88006ff4b818 EFLAGS: 00010206
[203748.703389] RAX: 0000000008620029 RBX: ffff88006ff4b910 RCX: 0000000000000000
[203748.703885] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 00000000023079fe
[203748.704382] RBP: ffff88006ff4b8d8 R08: 0000000000000000 R09: ffff8807578c25b0
[203748.704877] R10: 000000000f637376 R11: 000000003030322e R12: 0000000000000000
[203748.705373] R13: ffff88006ff4b910 R14: ffff880732fe38f0 R15: 0000000000000000
[203748.705871] FS: 00007f401992c700(0000) GS:ffff880bfebc0000(0000) knlGS:0000000000000000
[203748.706370] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[203748.706627] CR2: 00007f4019252440 CR3: 00000000a621e000 CR4: 0000000000060670
[203748.707124] Stack:
[203748.707371] ffff88006ff4b828 ffffffffa0609f52 ffff88006ff4b838 0000000000000001
[203748.707885] 0000000000000000 0000000000000000 ffff880bf67c3800 ffffffffa05eca00
[203748.708399] 00000000023079ff ffffffff81c58b80 0000000000000000 0000000000000000
[203748.708915] Call Trace:
[203748.709175] [<ffffffffa0609f52>] ? ocfs2_inode_cache_io_unlock+0x12/0x20 [ocfs2]
[203748.709680] [<ffffffffa05eca00>] ? ocfs2_empty_dir_filldir+0x80/0x80 [ocfs2]
[203748.710185] [<ffffffffa05ec0cb>] ocfs2_read_dir_block_direct+0x3b/0x200 [ocfs2]
[203748.710691] [<ffffffffa05f0fbf>] ocfs2_prepare_dx_dir_for_insert.isra.57+0x19f/0xf60 [ocfs2]
[203748.711204] [<ffffffffa065660f>] ? ocfs2_metadata_cache_io_unlock+0x1f/0x30 [ocfs2]
[203748.711716] [<ffffffffa05f4f3a>] ocfs2_prepare_dir_for_insert+0x13a/0x890 [ocfs2]
[203748.712227] [<ffffffffa05f442e>] ? ocfs2_check_dir_for_entry+0x8e/0x140 [ocfs2]
[203748.712737] [<ffffffffa061b2f2>] ocfs2_mknod+0x4b2/0x1370 [ocfs2]
[203748.713003] [<ffffffffa061c385>] ocfs2_create+0x65/0x170 [ocfs2]
[203748.713263] [<ffffffff8121714b>] vfs_create+0xdb/0x150
[203748.713518] [<ffffffff8121b225>] do_last+0x815/0x1210
[203748.713772] [<ffffffff812192e9>] ? path_init+0xb9/0x450
[203748.714123] [<ffffffff8121bca0>] path_openat+0x80/0x600
[203748.714378] [<ffffffff811bcd45>] ? handle_pte_fault+0xd15/0x1620
[203748.714634] [<ffffffff8121d7ba>] do_filp_open+0x3a/0xb0
[203748.714888] [<ffffffff8122a767>] ? __alloc_fd+0xa7/0x130
[203748.715143] [<ffffffff81209ffc>] do_sys_open+0x12c/0x220
[203748.715403] [<ffffffff81026ddb>] ? syscall_trace_enter_phase1+0x11b/0x180
[203748.715668] [<ffffffff816f0c9f>] ? system_call_after_swapgs+0xe9/0x190
[203748.715928] [<ffffffff8120a10e>] SyS_open+0x1e/0x20
[203748.716184] [<ffffffff816f0d5e>] system_call_fastpath+0x18/0xd7
[203748.716440] Code: 00 00 48 8b 7b 08 48 83 c3 10 45 89 f8 44 89 e1 44 89 f2 4c 89 ee e8 07 06 11 e1 48 8b 03 48 85 c0 75 df 8b 5d c8 e9 4d fa ff ff <0f> 0b 48 8b 7d a0 e8 dc c6 06 00 48 b8 00 00 00 00 00 00 00 10
[203748.717505] RIP [<ffffffffa05e9f09>] ocfs2_read_blocks+0x669/0x7f0 [ocfs2]
[203748.717775] RSP <ffff88006ff4b818>
Joesph ever reported a similar panic.
Link: https://oss.oracle.com/pipermail/ocfs2-devel/2013-May/008931.html
Link: http://lkml.kernel.org/r/20180912063207.29484-1-junxiao.bi@oracle.com
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Changwei Ge <ge.changwei@h3c.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
9092c71bb724 ("mm: use sc->priority for slab shrink targets") changed the
way that the target slab pressure is calculated and made it
priority-based:
delta = freeable >> priority;
delta *= 4;
do_div(delta, shrinker->seeks);
The problem is that on a default priority (which is 12) no pressure is
applied at all, if the number of potentially reclaimable objects is less
than 4096 (1<<12).
This causes the last objects on slab caches of no longer used cgroups to
(almost) never get reclaimed. It's obviously a waste of memory.
It can be especially painful, if these stale objects are holding a
reference to a dying cgroup. Slab LRU lists are reparented on memcg
offlining, but corresponding objects are still holding a reference to the
dying cgroup. If we don't scan these objects, the dying cgroup can't go
away. Most likely, the parent cgroup hasn't any directly charged objects,
only remaining objects from dying children cgroups. So it can easily hold
a reference to hundreds of dying cgroups.
If there are no big spikes in memory pressure, and new memory cgroups are
created and destroyed periodically, this causes the number of dying
cgroups grow steadily, causing a slow-ish and hard-to-detect memory
"leak". It's not a real leak, as the memory can be eventually reclaimed,
but it could not happen in a real life at all. I've seen hosts with a
steadily climbing number of dying cgroups, which doesn't show any signs of
a decline in months, despite the host is loaded with a production
workload.
It is an obvious waste of memory, and to prevent it, let's apply a minimal
pressure even on small shrinker lists. E.g. if there are freeable
objects, let's scan at least min(freeable, scan_batch) objects.
This fix significantly improves a chance of a dying cgroup to be
reclaimed, and together with some previous patches stops the steady growth
of the dying cgroups number on some of our hosts.
Link: http://lkml.kernel.org/r/20180905230759.12236-1-guro@fb.com
Fixes: 9092c71bb724 ("mm: use sc->priority for slab shrink targets")
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Rik van Riel <riel@surriel.com>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Link: http://lkml.kernel.org/r/20180821133424.18716-1-yuehaibing@huawei.com
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Directories and inodes don't necessarily need to be in the same lockdep
class. For ex, hugetlbfs splits them out too to prevent false positives
in lockdep. Annotate correctly after new inode creation. If its a
directory inode, it will be put into a different class.
This should fix a lockdep splat reported by syzbot:
> ======================================================
> WARNING: possible circular locking dependency detected
> 4.18.0-rc8-next-20180810+ #36 Not tainted
> ------------------------------------------------------
> syz-executor900/4483 is trying to acquire lock:
> 00000000d2bfc8fe (&sb->s_type->i_mutex_key#9){++++}, at: inode_lock
> include/linux/fs.h:765 [inline]
> 00000000d2bfc8fe (&sb->s_type->i_mutex_key#9){++++}, at:
> shmem_fallocate+0x18b/0x12e0 mm/shmem.c:2602
>
> but task is already holding lock:
> 0000000025208078 (ashmem_mutex){+.+.}, at: ashmem_shrink_scan+0xb4/0x630
> drivers/staging/android/ashmem.c:448
>
> which lock already depends on the new lock.
>
> -> #2 (ashmem_mutex){+.+.}:
> __mutex_lock_common kernel/locking/mutex.c:925 [inline]
> __mutex_lock+0x171/0x1700 kernel/locking/mutex.c:1073
> mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1088
> ashmem_mmap+0x55/0x520 drivers/staging/android/ashmem.c:361
> call_mmap include/linux/fs.h:1844 [inline]
> mmap_region+0xf27/0x1c50 mm/mmap.c:1762
> do_mmap+0xa10/0x1220 mm/mmap.c:1535
> do_mmap_pgoff include/linux/mm.h:2298 [inline]
> vm_mmap_pgoff+0x213/0x2c0 mm/util.c:357
> ksys_mmap_pgoff+0x4da/0x660 mm/mmap.c:1585
> __do_sys_mmap arch/x86/kernel/sys_x86_64.c:100 [inline]
> __se_sys_mmap arch/x86/kernel/sys_x86_64.c:91 [inline]
> __x64_sys_mmap+0xe9/0x1b0 arch/x86/kernel/sys_x86_64.c:91
> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> -> #1 (&mm->mmap_sem){++++}:
> __might_fault+0x155/0x1e0 mm/memory.c:4568
> _copy_to_user+0x30/0x110 lib/usercopy.c:25
> copy_to_user include/linux/uaccess.h:155 [inline]
> filldir+0x1ea/0x3a0 fs/readdir.c:196
> dir_emit_dot include/linux/fs.h:3464 [inline]
> dir_emit_dots include/linux/fs.h:3475 [inline]
> dcache_readdir+0x13a/0x620 fs/libfs.c:193
> iterate_dir+0x48b/0x5d0 fs/readdir.c:51
> __do_sys_getdents fs/readdir.c:231 [inline]
> __se_sys_getdents fs/readdir.c:212 [inline]
> __x64_sys_getdents+0x29f/0x510 fs/readdir.c:212
> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> -> #0 (&sb->s_type->i_mutex_key#9){++++}:
> lock_acquire+0x1e4/0x540 kernel/locking/lockdep.c:3924
> down_write+0x8f/0x130 kernel/locking/rwsem.c:70
> inode_lock include/linux/fs.h:765 [inline]
> shmem_fallocate+0x18b/0x12e0 mm/shmem.c:2602
> ashmem_shrink_scan+0x236/0x630 drivers/staging/android/ashmem.c:455
> ashmem_ioctl+0x3ae/0x13a0 drivers/staging/android/ashmem.c:797
> vfs_ioctl fs/ioctl.c:46 [inline]
> file_ioctl fs/ioctl.c:501 [inline]
> do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
> ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
> __do_sys_ioctl fs/ioctl.c:709 [inline]
> __se_sys_ioctl fs/ioctl.c:707 [inline]
> __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> other info that might help us debug this:
>
> Chain exists of:
> &sb->s_type->i_mutex_key#9 --> &mm->mmap_sem --> ashmem_mutex
>
> Possible unsafe locking scenario:
>
> CPU0 CPU1
> ---- ----
> lock(ashmem_mutex);
> lock(&mm->mmap_sem);
> lock(ashmem_mutex);
> lock(&sb->s_type->i_mutex_key#9);
>
> *** DEADLOCK ***
>
> 1 lock held by syz-executor900/4483:
> #0: 0000000025208078 (ashmem_mutex){+.+.}, at:
> ashmem_shrink_scan+0xb4/0x630 drivers/staging/android/ashmem.c:448
Link: http://lkml.kernel.org/r/20180821231835.166639-1-joel@joelfernandes.org
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reported-by: syzbot <syzkaller@googlegroups.com>
Reviewed-by: NeilBrown <neilb@suse.com>
Suggested-by: NeilBrown <neilb@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
The 'm' kcore_list item could point to kclist_head, and it is incorrect to
look at m->addr / m->size in this case.
There is no choice but to run through the list of entries for every
address if we did not find any entry in the previous iteration
Reset 'm' to NULL in that case at Omar Sandoval's suggestion.
[akpm@linux-foundation.org: add comment]
Link: http://lkml.kernel.org/r/1536100702-28706-1-git-send-email-asmadeus@codewreck.org
Fixes: bf991c2231117 ("proc/kcore: optimize multiple page reads")
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Omar Sandoval <osandov@osandov.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: James Morse <james.morse@arm.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Deferred struct page init is needed only on systems with large amount of
physical memory to improve boot performance. 32-bit systems do not
benefit from this feature.
Jiri reported a problem where deferred struct pages do not work well with
x86-32:
[ 0.035162] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)
[ 0.035725] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)
[ 0.036269] Initializing CPU#0
[ 0.036513] Initializing HighMem for node 0 (00036ffe:0007ffe0)
[ 0.038459] page:f6780000 is uninitialized and poisoned
[ 0.038460] raw: ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff ffffffff
[ 0.039509] page dumped because: VM_BUG_ON_PAGE(1 && PageCompound(page))
[ 0.040038] ------------[ cut here ]------------
[ 0.040399] kernel BUG at include/linux/page-flags.h:293!
[ 0.040823] invalid opcode: 0000 [#1] SMP PTI
[ 0.041166] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc1_pt_jiri #9
[ 0.041694] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-20171110_100015-anatol 04/01/2014
[ 0.042496] EIP: free_highmem_page+0x64/0x80
[ 0.042839] Code: 13 46 d8 c1 e8 18 5d 83 e0 03 8d 04 c0 c1 e0 06 ff 80 ec 5f 44 d8 c3 8d b4 26 00 00 00 00 ba 08 65 28 d8 89 d8 e8 fc 71 02 00 <0f> 0b 8d 76 00 8d bc 27 00 00 00 00 ba d0 b1 26 d8 89 d8 e8 e4 71
[ 0.044338] EAX: 0000003c EBX: f6780000 ECX: 00000000 EDX: d856cbe8
[ 0.044868] ESI: 0007ffe0 EDI: d838df20 EBP: d838df00 ESP: d838defc
[ 0.045372] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210086
[ 0.045913] CR0: 80050033 CR2: 00000000 CR3: 18556000 CR4: 00040690
[ 0.046413] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[ 0.046913] DR6: fffe0ff0 DR7: 00000400
[ 0.047220] Call Trace:
[ 0.047419] add_highpages_with_active_regions+0xbd/0x10d
[ 0.047854] set_highmem_pages_init+0x5b/0x71
[ 0.048202] mem_init+0x2b/0x1e8
[ 0.048460] start_kernel+0x1d2/0x425
[ 0.048757] i386_start_kernel+0x93/0x97
[ 0.049073] startup_32_smp+0x164/0x168
[ 0.049379] Modules linked in:
[ 0.049626] ---[ end trace 337949378db0abbb ]---
We free highmem pages before their struct pages are initialized:
mem_init()
set_highmem_pages_init()
add_highpages_with_active_regions()
free_highmem_page()
.. Access uninitialized struct page here..
Because there is no reason to have this feature on 32-bit systems, just
disable it.
Link: http://lkml.kernel.org/r/20180831150506.31246-1-pavel.tatashin@microsoft.com
Fixes: 2e3ca40f03bb ("mm: relax deferred struct page requirements")
Signed-off-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Reported-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Make the clone and fork syscalls return EAGAIN when the limit on the
number of pids /proc/sys/kernel/pid_max is exceeded.
Currently, when the pid_max limit is exceeded, the kernel will return
ENOSPC from the fork and clone syscalls. This is contrary to the
documented behaviour, which explicitly calls out the pid_max case as one
where EAGAIN should be returned. It also leads to really confusing error
messages in userspace programs which will complain about a lack of disk
space when they fail to create processes/threads for this reason.
This error is being returned because alloc_pid() uses the idr api to find
a new pid; when there are none available, idr_alloc_cyclic() returns
-ENOSPC, and this is being propagated back to userspace.
This behaviour has been broken before, and was explicitly fixed in
commit 35f71bc0a09a ("fork: report pid reservation failure properly"),
so I think -EAGAIN is definitely the right thing to return in this case.
The current behaviour change dates from commit 95846ecf9dac ("pid:
replace pid bitmap implementation with IDR AIP") and was I believe
unintentional.
This patch has no impact on the case where allocating a pid fails because
the child reaper for the namespace is dead; that case will still return
-ENOMEM.
Link: http://lkml.kernel.org/r/20180903111016.46461-1-ktsanaktsidis@zendesk.com
Fixes: 95846ecf9dac ("pid: replace pid bitmap implementation with IDR AIP")
Signed-off-by: KJ Tsanaktsidis <ktsanaktsidis@zendesk.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Gargi Sharma <gs051095@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
Dave Hansen
Rik van Riel
Peter Zijlstra
Borislav Petkov
Ingo Molnar
Baoquan He
Lianbo Jiang
Takuya Yamamoto
Thomas Gleixner
Greg Kroah-Hartman
Omar Sandoval
Feng Tang
Junxiao Bi
Roman Gushchin
YueHaibing
Joel Fernandes (Google)
Dominique Martinet
Pasha Tatashin
KJ Tsanaktsidis