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  1. Sep 12, 2022
    • Borislav Petkov's avatar
      scripts/decodecode: improve faulting line determination · 765f2bf0
      Borislav Petkov authored 
      There are cases where the IP pointer in a Code: line in an oops doesn't
point at the beginning of an instruction:

Code: 0f bd c2 e9 a0 cd b5 e4 48 0f bd c2 e9 97 cd b5 e4 0f 1f 80 00 00 00 00 \
	  e9 8b cd b5 e4 0f 1f 00 66 0f a3 d0 e9 7f cd b5 e4 0f 1f <80> 00 00 00 \
	  00 0f a3 d0 e9 70 cd b5 e4 48 0f a3 d0 e9 67 cd b5

  e9 7f cd b5 e4          jmp    0xffffffffe4b5cda8
  0f 1f 80 00 00 00 00    nopl   0x0(%rax)
	^^

and the current way of determining the faulting instruction line doesn't
work because disassembled instructions are counted from the IP byte to
the end and when that thing points in the middle, the trailing bytes can
be interpreted as different insns:

  Code starting with the faulting instruction
  ===========================================
     0:   80 00 00                addb   $0x0,(%rax)
     3:   00 00                   add    %al,(%rax)

whereas, this is part of

0f 1f 80 00 00 00 00    nopl   0x0(%rax)

     5:   0f a3 d0                bt     %edx,%eax
     ...

leading to:

  1d:   0f 1f 00                nopl   (%rax)
  20:   66 0f a3 d0             bt     %dx,%ax
  24:*  e9 7f cd b5 e4          jmp    0xffffffffe4b5cda8               <-- trapping instruction
  29:   0f 1f 80 00 00 00 00    nopl   0x0(%rax)
  30:   0f a3 d0                bt     %edx,%eax

which is the wrong faulting instruction.

Change the way the faulting line number is determined by matching the
opcode bytes from the beginning, leading to correct output:

  1d:   0f 1f 00                nopl   (%rax)
  20:   66 0f a3 d0             bt     %dx,%ax
  24:   e9 7f cd b5 e4          jmp    0xffffffffe4b5cda8
  29:*  0f 1f 80 00 00 00 00    nopl   0x0(%rax)                <-- trapping instruction
  30:   0f a3 d0                bt     %edx,%eax

While at it, make decodecode use bash as the interpreter - that thing
should be present on everything by now. It simplifies the code a lot
too.

Link: https://lkml.kernel.org/r/20220808085928.29840-1-bp@alien8.de


Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      765f2bf0
    • Fabio M. De Francesco's avatar
      hfsplus: convert kmap() to kmap_local_page() in btree.c · 9f25f357
      Fabio M. De Francesco authored 
      kmap() is being deprecated in favor of kmap_local_page().

There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap's pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.

With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts). 
It is faster than kmap() in kernels with HIGHMEM enabled.  Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and are still valid.

Since its use in btree.c is safe everywhere, it should be preferred.

Therefore, replace kmap() with kmap_local_page() in btree.c.

Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.

Link: https://lkml.kernel.org/r/20220809203105.26183-5-fmdefrancesco@gmail.com


Signed-off-by: default avatarFabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarViacheslav Dubeyko <slava@dubeyko.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      9f25f357
    • Fabio M. De Francesco's avatar
      hfsplus: convert kmap() to kmap_local_page() in bitmap.c · f9ef3b95
      Fabio M. De Francesco authored 
      kmap() is being deprecated in favor of kmap_local_page().

There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap's pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.

With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts). 
It is faster than kmap() in kernels with HIGHMEM enabled.  Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and are still valid.

Since its use in bitmap.c is safe everywhere, it should be preferred.

Therefore, replace kmap() with kmap_local_page() in bitmap.c.

Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.

Link: https://lkml.kernel.org/r/20220809203105.26183-4-fmdefrancesco@gmail.com


Signed-off-by: default avatarFabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarViacheslav Dubeyko <slava@dubeyko.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      f9ef3b95
    • Fabio M. De Francesco's avatar
      hfsplus: convert kmap() to kmap_local_page() in bnode.c · 6c3014a6
      Fabio M. De Francesco authored 
      kmap() is being deprecated in favor of kmap_local_page().

Two main problems with kmap(): (1) It comes with an overhead as mapping
space is restricted and protected by a global lock for synchronization and
(2) it also requires global TLB invalidation when the kmap's pool wraps
and it might block when the mapping space is fully utilized until a slot
becomes available.

With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts). 
It is faster than kmap() in kernels with HIGHMEM enabled.  Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and still valid.

Since its use in bnode.c is safe everywhere, it should be preferred.

Therefore, replace kmap() with kmap_local_page() in bnode.c.  Where
possible, use the suited standard helpers (memzero_page(), memcpy_page())
instead of open coding kmap_local_page() plus memset() or memcpy().

Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.

Link: https://lkml.kernel.org/r/20220809203105.26183-3-fmdefrancesco@gmail.com


Signed-off-by: default avatarFabio M. De Francesco <fmdefrancesco@gmail.com>
Suggested-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarViacheslav Dubeyko <slava@dubeyko.com>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      6c3014a6
    • Fabio M. De Francesco's avatar
      hfsplus: unmap the page in the "fail_page" label · f5b23d67
      Fabio M. De Francesco authored 
      Patch series "hfsplus: Replace kmap() with kmap_local_page()".

kmap() is being deprecated in favor of kmap_local_page().

There are two main problems with kmap(): (1) It comes with an overhead as
mapping space is restricted and protected by a global lock for
synchronization and (2) it also requires global TLB invalidation when the
kmap’s pool wraps and it might block when the mapping space is fully
utilized until a slot becomes available.

With kmap_local_page() the mappings are per thread, CPU local, can take
page faults, and can be called from any context (including interrupts). 
It is faster than kmap() in kernels with HIGHMEM enabled.  Furthermore,
the tasks can be preempted and, when they are scheduled to run again, the
kernel virtual addresses are restored and still valid.

Since its use in fs/hfsplus is safe everywhere, it should be preferred.

Therefore, replace kmap() with kmap_local_page() in fs/hfsplus.  Where
possible, use the suited standard helpers (memzero_page(), memcpy_page())
instead of open coding kmap_local_page() plus memset() or memcpy().

Fix a bug due to a page being not unmapped if the code jumps to the
"fail_page" label (1/4).

Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.


This patch (of 4):

Several paths within hfs_btree_open() jump to the "fail_page" label where
put_page() is called while the page is still mapped.

Call kunmap() to unmap the page soon before put_page().

Link: https://lkml.kernel.org/r/20220809203105.26183-1-fmdefrancesco@gmail.com
Link: https://lkml.kernel.org/r/20220809203105.26183-2-fmdefrancesco@gmail.com


Signed-off-by: default avatarFabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: default avatarIra Weiny <ira.weiny@intel.com>
Reviewed-by: default avatarViacheslav Dubeyko <slava@dubeyko.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      f5b23d67
  3. Aug 29, 2022
  5. Aug 28, 2022
  7. Aug 27, 2022
    • Zhengjun Xing's avatar
      perf stat: Capitalize topdown metrics' names · 48648548
      Zhengjun Xing authored 
      

Capitalize topdown metrics' names to follow the intel SDM.

Before:

 # ./perf stat -a  sleep 1

 Performance counter stats for 'system wide':

        228,094.05 msec cpu-clock                        #  225.026 CPUs utilized
               842      context-switches                 #    3.691 /sec
               224      cpu-migrations                   #    0.982 /sec
                70      page-faults                      #    0.307 /sec
        23,164,105      cycles                           #    0.000 GHz
        29,403,446      instructions                     #    1.27  insn per cycle
         5,268,185      branches                         #   23.097 K/sec
            33,239      branch-misses                    #    0.63% of all branches
       136,248,990      slots                            #  597.337 K/sec
        32,976,450      topdown-retiring                 #     24.2% retiring
         4,651,918      topdown-bad-spec                 #      3.4% bad speculation
        26,148,695      topdown-fe-bound                 #     19.2% frontend bound
        72,515,776      topdown-be-bound                 #     53.2% backend bound
         6,008,540      topdown-heavy-ops                #      4.4% heavy operations       #     19.8% light operations
         3,934,049      topdown-br-mispredict            #      2.9% branch mispredict      #      0.5% machine clears
        16,655,439      topdown-fetch-lat                #     12.2% fetch latency          #      7.0% fetch bandwidth
        41,635,972      topdown-mem-bound                #     30.5% memory bound           #     22.7% Core bound

       1.013634593 seconds time elapsed

After:

 # ./perf stat -a  sleep 1

 Performance counter stats for 'system wide':

        228,081.94 msec cpu-clock                        #  225.003 CPUs utilized
               824      context-switches                 #    3.613 /sec
               224      cpu-migrations                   #    0.982 /sec
                67      page-faults                      #    0.294 /sec
        22,647,423      cycles                           #    0.000 GHz
        28,870,551      instructions                     #    1.27  insn per cycle
         5,167,099      branches                         #   22.655 K/sec
            32,383      branch-misses                    #    0.63% of all branches
       133,411,074      slots                            #  584.926 K/sec
        32,352,607      topdown-retiring                 #     24.3% Retiring
         4,456,977      topdown-bad-spec                 #      3.3% Bad Speculation
        25,626,487      topdown-fe-bound                 #     19.2% Frontend Bound
        70,955,316      topdown-be-bound                 #     53.2% Backend Bound
         5,834,844      topdown-heavy-ops                #      4.4% Heavy Operations       #     19.9% Light Operations
         3,738,781      topdown-br-mispredict            #      2.8% Branch Mispredict      #      0.5% Machine Clears
        16,286,803      topdown-fetch-lat                #     12.2% Fetch Latency          #      7.0% Fetch Bandwidth
        40,802,069      topdown-mem-bound                #     30.6% Memory Bound           #     22.6% Core Bound

       1.013683125 seconds time elapsed

Reviewed-by: default avatarKan Liang <kan.liang@linux.intel.com>
Signed-off-by: default avatarXing Zhengjun <zhengjun.xing@linux.intel.com>
Acked-by: default avatarIan Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220825015458.3252239-1-zhengjun.xing@linux.intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      48648548
    • Kan Liang's avatar
      perf docs: Update the documentation for the save_type filter · 3126204c
      Kan Liang authored 
      

Update the documentation to reflect the kernel changes.

Signed-off-by: default avatarKan Liang <kan.liang@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20220816125612.2042397-2-kan.liang@linux.intel.com


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      3126204c