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  1. Apr 25, 2018
    • Eric W. Biederman's avatar
      signal: Ensure every siginfo we send has all bits initialized · 3eb0f519
      Eric W. Biederman authored
      
      
      Call clear_siginfo to ensure every stack allocated siginfo is properly
      initialized before being passed to the signal sending functions.
      
      Note: It is not safe to depend on C initializers to initialize struct
      siginfo on the stack because C is allowed to skip holes when
      initializing a structure.
      
      The initialization of struct siginfo in tracehook_report_syscall_exit
      was moved from the helper user_single_step_siginfo into
      tracehook_report_syscall_exit itself, to make it clear that the local
      variable siginfo gets fully initialized.
      
      In a few cases the scope of struct siginfo has been reduced to make it
      clear that siginfo siginfo is not used on other paths in the function
      in which it is declared.
      
      Instances of using memset to initialize siginfo have been replaced
      with calls clear_siginfo for clarity.
      
      Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      3eb0f519
  2. Apr 19, 2018
    • Dmitry V. Levin's avatar
      sparc: fix compat siginfo ABI regression · 32772c9e
      Dmitry V. Levin authored
      Starting with commit v4.14-rc1~60^2^2~1, a SIGFPE signal sent via kill
      results to wrong values in si_pid and si_uid fields of compat siginfo_t.
      
      This happens due to FPE_FIXME being defined to 0 for sparc, and at the
      same time siginfo_layout() introduced by the same commit returns
      SIL_FAULT for SIGFPE if si_code == SI_USER and FPE_FIXME is defined to 0.
      
      Fix this regression by removing FPE_FIXME macro and changing all its users
      to assign FPE_FLTUNK to si_code instead of FPE_FIXME.
      
      Note that FPE_FLTUNK is a new macro introduced by commit
      266da65e.
      
      Tested with commit v4.16-11958-g16e205cf42da.
      
      This bug was found by strace test suite.
      
      In the discussion about FPE_FLTUNK on sparc David Miller said:
      > Eric, feel free to do something similar on Sparc.
      
      Link: https://github.com/strace/strace/issues/21
      
      
      Fixes: cc731525 ("signal: Remove kernel interal si_code magic")
      Fixes: 2.3.41
      Cc: David Miller <davem@davemloft.net>
      Cc: sparclinux@vger.kernel.org
      Conceptually-Acked-By: default avatarDavid Miller <davem@davemloft.net>
      Thanks-to: Anatoly Pugachev <matorola@gmail.com>
      Signed-off-by: default avatarDmitry V. Levin <ldv@altlinux.org>
      Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
      32772c9e
  3. Apr 14, 2018
  4. Apr 11, 2018
    • Kees Cook's avatar
      exec: pass stack rlimit into mm layout functions · 8f2af155
      Kees Cook authored
      Patch series "exec: Pin stack limit during exec".
      
      Attempts to solve problems with the stack limit changing during exec
      continue to be frustrated[1][2].  In addition to the specific issues
      around the Stack Clash family of flaws, Andy Lutomirski pointed out[3]
      other places during exec where the stack limit is used and is assumed to
      be unchanging.  Given the many places it gets used and the fact that it
      can be manipulated/raced via setrlimit() and prlimit(), I think the only
      way to handle this is to move away from the "current" view of the stack
      limit and instead attach it to the bprm, and plumb this down into the
      functions that need to know the stack limits.  This series implements
      the approach.
      
      [1] 04e35f44 ("exec: avoid RLIMIT_STACK races with prlimit()")
      [2] 779f4e1c ("Revert "exec: avoid RLIMIT_STACK races with prlimit()"")
      [3] to security@kernel.org, "Subject: existing rlimit races?"
      
      This patch (of 3):
      
      Since it is possible that the stack rlimit can change externally during
      exec (either via another thread calling setrlimit() or another process
      calling prlimit()), provide a way to pass the rlimit down into the
      per-architecture mm layout functions so that the rlimit can stay in the
      bprm structure instead of sitting in the signal structure until exec is
      finalized.
      
      Link: http://lkml.kernel.org/r/1518638796-20819-2-git-send-email-keescook@chromium.org
      
      
      Signed-off-by: default avatarKees Cook <keescook@chromium.org>
      Cc: Michal Hocko <mhocko@kernel.org>
      Cc: Ben Hutchings <ben@decadent.org.uk>
      Cc: Willy Tarreau <w@1wt.eu>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Laura Abbott <labbott@redhat.com>
      Cc: Greg KH <greg@kroah.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Ben Hutchings <ben.hutchings@codethink.co.uk>
      Cc: Brad Spengler <spender@grsecurity.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8f2af155
  5. Apr 07, 2018
    • Masahiro Yamada's avatar
      kbuild: mark $(targets) as .SECONDARY and remove .PRECIOUS markers · 54a702f7
      Masahiro Yamada authored
      
      
      GNU Make automatically deletes intermediate files that are updated
      in a chain of pattern rules.
      
      Example 1) %.dtb.o <- %.dtb.S <- %.dtb <- %.dts
      Example 2) %.o <- %.c <- %.c_shipped
      
      A couple of makefiles mark such targets as .PRECIOUS to prevent Make
      from deleting them, but the correct way is to use .SECONDARY.
      
        .SECONDARY
          Prerequisites of this special target are treated as intermediate
          files but are never automatically deleted.
      
        .PRECIOUS
          When make is interrupted during execution, it may delete the target
          file it is updating if the file was modified since make started.
          If you mark the file as precious, make will never delete the file
          if interrupted.
      
      Both can avoid deletion of intermediate files, but the difference is
      the behavior when Make is interrupted; .SECONDARY deletes the target,
      but .PRECIOUS does not.
      
      The use of .PRECIOUS is relatively rare since we do not want to keep
      partially constructed (possibly corrupted) targets.
      
      Another difference is that .PRECIOUS works with pattern rules whereas
      .SECONDARY does not.
      
        .PRECIOUS: $(obj)/%.lex.c
      
      works, but
      
        .SECONDARY: $(obj)/%.lex.c
      
      has no effect.  However, for the reason above, I do not want to use
      .PRECIOUS which could cause obscure build breakage.
      
      The targets specified as .SECONDARY must be explicit.  $(targets)
      contains all targets that need to include .*.cmd files.  So, the
      intermediates you want to keep are mostly in there.  Therefore, mark
      $(targets) as .SECONDARY.  It means primary targets are also marked
      as .SECONDARY, but I do not see any drawback for this.
      
      I replaced some .SECONDARY / .PRECIOUS markers with 'targets'.  This
      will make Kbuild search for non-existing .*.cmd files, but this is
      not a noticeable performance issue.
      
      Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      Acked-by: default avatarFrank Rowand <frowand.list@gmail.com>
      Acked-by: default avatarIngo Molnar <mingo@kernel.org>
      54a702f7
  6. Apr 06, 2018
    • Randy Dunlap's avatar
      headers: untangle kmemleak.h from mm.h · 514c6032
      Randy Dunlap authored
      Currently <linux/slab.h> #includes <linux/kmemleak.h> for no obvious
      reason.  It looks like it's only a convenience, so remove kmemleak.h
      from slab.h and add <linux/kmemleak.h> to any users of kmemleak_* that
      don't already #include it.  Also remove <linux/kmemleak.h> from source
      files that do not use it.
      
      This is tested on i386 allmodconfig and x86_64 allmodconfig.  It would
      be good to run it through the 0day bot for other $ARCHes.  I have
      neither the horsepower nor the storage space for the other $ARCHes.
      
      Update: This patch has been extensively build-tested by both the 0day
      bot & kisskb/ozlabs build farms.  Both of them reported 2 build failures
      for which patches are included here (in v2).
      
      [ slab.h is the second most used header file after module.h; kernel.h is
        right there with slab.h. There could be some minor error in the
        counting due to some #includes having comments after them and I didn't
        combine all of those. ]
      
      [akpm@linux-foundation.org: security/keys/big_key.c needs vmalloc.h, per sfr]
      Link: http://lkml.kernel.org/r/e4309f98-3749-93e1-4bb7-d9501a39d015@infradead.org
      Link: http://kisskb.ellerman.id.au/kisskb/head/13396/
      
      
      Signed-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
      Reviewed-by: default avatarIngo Molnar <mingo@kernel.org>
      Reported-by: Michael Ellerman <mpe@ellerman.id.au>	[2 build failures]
      Reported-by: Fengguang Wu <fengguang.wu@intel.com>	[2 build failures]
      Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: Wei Yongjun <weiyongjun1@huawei.com>
      Cc: Luis R. Rodriguez <mcgrof@kernel.org>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
      Cc: John Johansen <john.johansen@canonical.com>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      514c6032
    • Huang Ying's avatar
      mm: fix races between swapoff and flush dcache · cb9f753a
      Huang Ying authored
      Thanks to commit 4b3ef9da ("mm/swap: split swap cache into 64MB
      trunks"), after swapoff the address_space associated with the swap
      device will be freed.  So page_mapping() users which may touch the
      address_space need some kind of mechanism to prevent the address_space
      from being freed during accessing.
      
      The dcache flushing functions (flush_dcache_page(), etc) in architecture
      specific code may access the address_space of swap device for anonymous
      pages in swap cache via page_mapping() function.  But in some cases
      there are no mechanisms to prevent the swap device from being swapoff,
      for example,
      
        CPU1					CPU2
        __get_user_pages()			swapoff()
          flush_dcache_page()
            mapping = page_mapping()
              ...				  exit_swap_address_space()
              ...				    kvfree(spaces)
              mapping_mapped(mapping)
      
      The address space may be accessed after being freed.
      
      But from cachetlb.txt and Russell King, flush_dcache_page() only care
      about file cache pages, for anonymous pages, flush_anon_page() should be
      used.  The implementation of flush_dcache_page() in all architectures
      follows this too.  They will check whether page_mapping() is NULL and
      whether mapping_mapped() is true to determine whether to flush the
      dcache immediately.  And they will use interval tree (mapping->i_mmap)
      to find all user space mappings.  While mapping_mapped() and
      mapping->i_mmap isn't used by anonymous pages in swap cache at all.
      
      So, to fix the race between swapoff and flush dcache, __page_mapping()
      is add to return the address_space for file cache pages and NULL
      otherwise.  All page_mapping() invoking in flush dcache functions are
      replaced with page_mapping_file().
      
      [akpm@linux-foundation.org: simplify page_mapping_file(), per Mike]
      Link: http://lkml.kernel.org/r/20180305083634.15174-1-ying.huang@intel.com
      
      
      Signed-off-by: default avatar"Huang, Ying" <ying.huang@intel.com>
      Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: Minchan Kim <minchan@kernel.org>
      Cc: Michal Hocko <mhocko@suse.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Chen Liqin <liqin.linux@gmail.com>
      Cc: Russell King <linux@armlinux.org.uk>
      Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: Vineet Gupta <vgupta@synopsys.com>
      Cc: Ley Foon Tan <lftan@altera.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      cb9f753a
  7. Apr 03, 2018
    • David S. Miller's avatar
      sparc64: Make atomic_xchg() an inline function rather than a macro. · d13864b6
      David S. Miller authored
      
      
      This avoids a lot of -Wunused warnings such as:
      
      ====================
      kernel/debug/debug_core.c: In function ‘kgdb_cpu_enter’:
      ./arch/sparc/include/asm/cmpxchg_64.h:55:22: warning: value computed is not used [-Wunused-value]
       #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
      
      ./arch/sparc/include/asm/atomic_64.h:86:30: note: in expansion of macro ‘xchg’
       #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
                                    ^~~~
      kernel/debug/debug_core.c:508:4: note: in expansion of macro ‘atomic_xchg’
          atomic_xchg(&kgdb_active, cpu);
          ^~~~~~~~~~~
      ====================
      
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      d13864b6
  8. Apr 02, 2018
  9. Mar 20, 2018
  10. Mar 18, 2018
  11. Mar 16, 2018
  12. Mar 15, 2018
    • David S. Miller's avatar
      sparc64: Fix regression in pmdp_invalidate(). · cfb61b5e
      David S. Miller authored
      
      
      pmdp_invalidate() was changed to update the pmd atomically
      (to not lose dirty/access bits) and return the original pmd
      value.
      
      However, in doing so, we lost a lot of the essential work that
      set_pmd_at() does, namely to update hugepage mapping counts and
      queuing up the batched TLB flush entry.
      
      Thus we were not flushing entries out of the TLB when making
      such PMD changes.
      
      Fix this by abstracting the accounting work of set_pmd_at() out into a
      separate function, and call it from pmdp_establish().
      
      Fixes: a8e654f0 ("sparc64: update pmdp_invalidate() to return old pmd value")
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      cfb61b5e
  13. Mar 12, 2018
    • Peter Zijlstra's avatar
      perf/core: Remove perf_event::group_entry · 8343aae6
      Peter Zijlstra authored
      
      
      Now that all the grouping is done with RB trees, we no longer need
      group_entry and can replace the whole thing with sibling_list.
      
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: David Carrillo-Cisneros <davidcc@google.com>
      Cc: Dmitri Prokhorov <Dmitry.Prohorov@intel.com>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Kan Liang <kan.liang@intel.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Stephane Eranian <eranian@google.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Valery Cherepennikov <valery.cherepennikov@intel.com>
      Cc: Vince Weaver <vincent.weaver@maine.edu>
      Cc: linux-kernel@vger.kernel.org
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      8343aae6
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