1. 04 Dec, 2015 3 commits
  2. 23 Aug, 2015 1 commit
    • Peter Zijlstra's avatar
      module: Fix locking in symbol_put_addr() · 275d7d44
      Peter Zijlstra authored
      Poma (on the way to another bug) reported an assertion triggering:
      
        [<ffffffff81150529>] module_assert_mutex_or_preempt+0x49/0x90
        [<ffffffff81150822>] __module_address+0x32/0x150
        [<ffffffff81150956>] __module_text_address+0x16/0x70
        [<ffffffff81150f19>] symbol_put_addr+0x29/0x40
        [<ffffffffa04b77ad>] dvb_frontend_detach+0x7d/0x90 [dvb_core]
      
      Laura Abbott <labbott@redhat.com> produced a patch which lead us to
      inspect symbol_put_addr(). This function has a comment claiming it
      doesn't need to disable preemption around the module lookup
      because it holds a reference to the module it wants to find, which
      therefore cannot go away.
      
      This is wrong (and a false optimization too, preempt_disable() is really
      rather cheap, and I doubt any of this is on uber critical paths,
      otherwise it would've retained a pointer to the actual module anyway and
      avoided the second lookup).
      
      While its true that the module cannot go away while we hold a reference
      on it, the data structure we do the lookup in very much _CAN_ change
      while we do the lookup. Therefore fix the comment and add the
      required preempt_disable().
      Reported-by: default avatarpoma <pomidorabelisima@gmail.com>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Fixes: a6e6abd5 ("module: remove module_text_address()")
      Cc: stable@kernel.org
      275d7d44
  3. 28 Jul, 2015 1 commit
  4. 08 Jul, 2015 1 commit
  5. 27 Jun, 2015 1 commit
  6. 22 Jun, 2015 1 commit
    • Dan Streetman's avatar
      module: add per-module param_lock · b51d23e4
      Dan Streetman authored
      Add a "param_lock" mutex to each module, and update params.c to use
      the correct built-in or module mutex while locking kernel params.
      Remove the kparam_block_sysfs_r/w() macros, replace them with direct
      calls to kernel_param_[un]lock(module).
      
      The kernel param code currently uses a single mutex to protect
      modification of any and all kernel params.  While this generally works,
      there is one specific problem with it; a module callback function
      cannot safely load another module, i.e. with request_module() or even
      with indirect calls such as crypto_has_alg().  If the module to be
      loaded has any of its params configured (e.g. with a /etc/modprobe.d/*
      config file), then the attempt will result in a deadlock between the
      first module param callback waiting for modprobe, and modprobe trying to
      lock the single kernel param mutex to set the new module's param.
      
      This fixes that by using per-module mutexes, so that each individual module
      is protected against concurrent changes in its own kernel params, but is
      not blocked by changes to other module params.  All built-in modules
      continue to use the built-in mutex, since they will always be loaded at
      runtime and references (e.g. request_module(), crypto_has_alg()) to them
      will never cause load-time param changing.
      
      This also simplifies the interface used by modules to block sysfs access
      to their params; while there are currently functions to block and unblock
      sysfs param access which are split up by read and write and expect a single
      kernel param to be passed, their actual operation is identical and applies
      to all params, not just the one passed to them; they simply lock and unlock
      the global param mutex.  They are replaced with direct calls to
      kernel_param_[un]lock(THIS_MODULE), which locks THIS_MODULE's param_lock, or
      if the module is built-in, it locks the built-in mutex.
      Suggested-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Signed-off-by: default avatarDan Streetman <ddstreet@ieee.org>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      b51d23e4
  7. 27 May, 2015 8 commits
    • Luis R. Rodriguez's avatar
      kernel/module.c: avoid ifdefs for sig_enforce declaration · 6727bb9c
      Luis R. Rodriguez authored
      There's no need to require an ifdef over the declaration
      of sig_enforce as IS_ENABLED() can be used. While at it,
      there's no harm in exposing this kernel parameter outside of
      CONFIG_MODULE_SIG as it'd be a no-op on non module sig
      kernels.
      
      Now, technically we should in theory be able to remove
      the #ifdef'ery over the declaration of the module parameter
      as we are also trusting the bool_enable_only code for
      CONFIG_MODULE_SIG kernels but for now remain paranoid
      and keep it.
      
      With time if no one can put a bullet through bool_enable_only
      and if there are no technical requirements over not exposing
      CONFIG_MODULE_SIG_FORCE with the measures in place by
      bool_enable_only we could remove this last ifdef.
      
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: linux-kernel@vger.kernel.org
      Cc: cocci@systeme.lip6.fr
      Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@suse.com>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      6727bb9c
    • Luis R. Rodriguez's avatar
      kernel/params.c: generalize bool_enable_only · d19f05d8
      Luis R. Rodriguez authored
      This takes out the bool_enable_only implementation from
      the module loading code and generalizes it so that others
      can make use of it.
      
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Jani Nikula <jani.nikula@intel.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: linux-kernel@vger.kernel.org
      Cc: cocci@systeme.lip6.fr
      Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@suse.com>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      d19f05d8
    • Luis R. Rodriguez's avatar
      kernel/module.c: use generic module param operaters for sig_enforce · 05f408dd
      Luis R. Rodriguez authored
      We're directly checking and modifying sig_enforce when needed instead
      of using the generic helpers. This prevents us from generalizing this
      helper so that others can use it. Use indirect helpers to allow us
      to generalize this code a bit and to make it a bit more clear what
      this is doing.
      
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Jani Nikula <jani.nikula@intel.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Kees Cook <keescook@chromium.org>
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: linux-kernel@vger.kernel.org
      Cc: cocci@systeme.lip6.fr
      Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@suse.com>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      05f408dd
    • Peter Zijlstra's avatar
      module: Rework module_addr_{min,max} · 4f666546
      Peter Zijlstra authored
      __module_address() does an initial bound check before doing the
      {list/tree} iteration to find the actual module. The bound variables
      are nowhere near the mod_tree cacheline, in fact they're nowhere near
      one another.
      
      module_addr_min lives in .data while module_addr_max lives in .bss
      (smarty pants GCC thinks the explicit 0 assignment is a mistake).
      
      Rectify this by moving the two variables into a structure together
      with the latch_tree_root to guarantee they all share the same
      cacheline and avoid hitting two extra cachelines for the lookup.
      
      While reworking the bounds code, move the bound update from allocation
      to insertion time, this avoids updating the bounds for a few error
      paths.
      
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      4f666546
    • Peter Zijlstra's avatar
      module: Use __module_address() for module_address_lookup() · b7df4d1b
      Peter Zijlstra authored
      Use the generic __module_address() addr to struct module lookup
      instead of open coding it once more.
      
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      b7df4d1b
    • Peter Zijlstra's avatar
      module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING · 6c9692e2
      Peter Zijlstra authored
      Andrew worried about the overhead on small systems; only use the fancy
      code when either perf or tracing is enabled.
      
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Requested-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      6c9692e2
    • Peter Zijlstra's avatar
      module: Optimize __module_address() using a latched RB-tree · 93c2e105
      Peter Zijlstra authored
      Currently __module_address() is using a linear search through all
      modules in order to find the module corresponding to the provided
      address. With a lot of modules this can take a lot of time.
      
      One of the users of this is kernel_text_address() which is employed
      in many stack unwinders; which in turn are used by perf-callchain and
      ftrace (possibly from NMI context).
      
      So by optimizing __module_address() we optimize many stack unwinders
      which are used by both perf and tracing in performance sensitive code.
      
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      93c2e105
    • Peter Zijlstra's avatar
      module: Sanitize RCU usage and locking · 0be964be
      Peter Zijlstra authored
      Currently the RCU usage in module is an inconsistent mess of RCU and
      RCU-sched, this is broken for CONFIG_PREEMPT where synchronize_rcu()
      does not imply synchronize_sched().
      
      Most usage sites use preempt_{dis,en}able() which is RCU-sched, but
      (most of) the modification sites use synchronize_rcu(). With the
      exception of the module bug list, which actually uses RCU.
      
      Convert everything over to RCU-sched.
      
      Furthermore add lockdep asserts to all sites, because it's not at all
      clear to me the required locking is observed, esp. on exported
      functions.
      
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Acked-by: default avatar"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      0be964be
  8. 26 May, 2015 1 commit
    • Peter Zijlstra's avatar
      module: Annotate module version magic · 926a59b1
      Peter Zijlstra authored
      Due to the new lockdep checks in the coming patch, we go:
      
      [    9.759380] ------------[ cut here ]------------
      [    9.759389] WARNING: CPU: 31 PID: 597 at ../kernel/module.c:216 each_symbol_section+0x121/0x130()
      [    9.759391] Modules linked in:
      [    9.759393] CPU: 31 PID: 597 Comm: modprobe Not tainted 4.0.0-rc1+ #65
      [    9.759393] Hardware name: Intel Corporation S2600GZ/S2600GZ, BIOS SE5C600.86B.02.02.0002.122320131210 12/23/2013
      [    9.759396]  ffffffff817d8676 ffff880424567ca8 ffffffff8157e98b 0000000000000001
      [    9.759398]  0000000000000000 ffff880424567ce8 ffffffff8105fbc7 ffff880424567cd8
      [    9.759400]  0000000000000000 ffffffff810ec160 ffff880424567d40 0000000000000000
      [    9.759400] Call Trace:
      [    9.759407]  [<ffffffff8157e98b>] dump_stack+0x4f/0x7b
      [    9.759410]  [<ffffffff8105fbc7>] warn_slowpath_common+0x97/0xe0
      [    9.759412]  [<ffffffff810ec160>] ? section_objs+0x60/0x60
      [    9.759414]  [<ffffffff8105fc2a>] warn_slowpath_null+0x1a/0x20
      [    9.759415]  [<ffffffff810ed9c1>] each_symbol_section+0x121/0x130
      [    9.759417]  [<ffffffff810eda01>] find_symbol+0x31/0x70
      [    9.759420]  [<ffffffff810ef5bf>] load_module+0x20f/0x2660
      [    9.759422]  [<ffffffff8104ef10>] ? __do_page_fault+0x190/0x4e0
      [    9.759426]  [<ffffffff815880ec>] ? retint_restore_args+0x13/0x13
      [    9.759427]  [<ffffffff815880ec>] ? retint_restore_args+0x13/0x13
      [    9.759433]  [<ffffffff810ae73d>] ? trace_hardirqs_on_caller+0x11d/0x1e0
      [    9.759437]  [<ffffffff812fcc0e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
      [    9.759439]  [<ffffffff815880ec>] ? retint_restore_args+0x13/0x13
      [    9.759441]  [<ffffffff810f1ade>] SyS_init_module+0xce/0x100
      [    9.759443]  [<ffffffff81587429>] system_call_fastpath+0x12/0x17
      [    9.759445] ---[ end trace 9294429076a9c644 ]---
      
      As per the comment this site should be fine, but lets wrap it in
      preempt_disable() anyhow to placate lockdep.
      
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Acked-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      926a59b1
  9. 20 May, 2015 2 commits
    • Luis R. Rodriguez's avatar
      driver-core: add driver module asynchronous probe support · f2411da7
      Luis R. Rodriguez authored
      Some init systems may wish to express the desire to have device drivers
      run their probe() code asynchronously. This implements support for this
      and allows userspace to request async probe as a preference through a
      generic shared device driver module parameter, async_probe.
      
      Implementation for async probe is supported through a module parameter
      given that since synchronous probe has been prevalent for years some
      userspace might exist which relies on the fact that the device driver
      will probe synchronously and the assumption that devices it provides
      will be immediately available after this.
      Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@suse.com>
      Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      f2411da7
    • Luis R. Rodriguez's avatar
      module: add extra argument for parse_params() callback · ecc86170
      Luis R. Rodriguez authored
      This adds an extra argument onto parse_params() to be used
      as a way to make the unused callback a bit more useful and
      generic by allowing the caller to pass on a data structure
      of its choice. An example use case is to allow us to easily
      make module parameters for every module which we will do
      next.
      
      @ parse @
      identifier name, args, params, num, level_min, level_max;
      identifier unknown, param, val, doing;
      type s16;
      @@
       extern char *parse_args(const char *name,
       			 char *args,
       			 const struct kernel_param *params,
       			 unsigned num,
       			 s16 level_min,
       			 s16 level_max,
      +			 void *arg,
       			 int (*unknown)(char *param, char *val,
      					const char *doing
      +					, void *arg
      					));
      
      @ parse_mod @
      identifier name, args, params, num, level_min, level_max;
      identifier unknown, param, val, doing;
      type s16;
      @@
       char *parse_args(const char *name,
       			 char *args,
       			 const struct kernel_param *params,
       			 unsigned num,
       			 s16 level_min,
       			 s16 level_max,
      +			 void *arg,
       			 int (*unknown)(char *param, char *val,
      					const char *doing
      +					, void *arg
      					))
      {
      	...
      }
      
      @ parse_args_found @
      expression R, E1, E2, E3, E4, E5, E6;
      identifier func;
      @@
      
      (
      	R =
      	parse_args(E1, E2, E3, E4, E5, E6,
      +		   NULL,
      		   func);
      |
      	R =
      	parse_args(E1, E2, E3, E4, E5, E6,
      +		   NULL,
      		   &func);
      |
      	R =
      	parse_args(E1, E2, E3, E4, E5, E6,
      +		   NULL,
      		   NULL);
      |
      	parse_args(E1, E2, E3, E4, E5, E6,
      +		   NULL,
      		   func);
      |
      	parse_args(E1, E2, E3, E4, E5, E6,
      +		   NULL,
      		   &func);
      |
      	parse_args(E1, E2, E3, E4, E5, E6,
      +		   NULL,
      		   NULL);
      )
      
      @ parse_args_unused depends on parse_args_found @
      identifier parse_args_found.func;
      @@
      
      int func(char *param, char *val, const char *unused
      +		 , void *arg
      		 )
      {
      	...
      }
      
      @ mod_unused depends on parse_args_found @
      identifier parse_args_found.func;
      expression A1, A2, A3;
      @@
      
      -	func(A1, A2, A3);
      +	func(A1, A2, A3, NULL);
      
      Generated-by: Coccinelle SmPL
      Cc: cocci@systeme.lip6.fr
      Cc: Tejun Heo <tj@kernel.org>
      Cc: Arjan van de Ven <arjan@linux.intel.com>
      Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Felipe Contreras <felipe.contreras@gmail.com>
      Cc: Ewan Milne <emilne@redhat.com>
      Cc: Jean Delvare <jdelvare@suse.de>
      Cc: Hannes Reinecke <hare@suse.de>
      Cc: Jani Nikula <jani.nikula@intel.com>
      Cc: linux-kernel@vger.kernel.org
      Reviewed-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Signed-off-by: default avatarLuis R. Rodriguez <mcgrof@suse.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      ecc86170
  10. 13 May, 2015 1 commit
  11. 08 May, 2015 1 commit
  12. 08 Apr, 2015 2 commits
  13. 23 Mar, 2015 3 commits
    • Kirill A. Shutemov's avatar
      module: do not print allocation-fail warning on bogus user buffer size · cc9e605d
      Kirill A. Shutemov authored
      init_module(2) passes user-specified buffer length directly to
      vmalloc(). It makes warn_alloc_failed() to print out a lot of info into
      dmesg if user specified insane size, like -1.
      
      Let's silence the warning. It doesn't add much value to -ENOMEM return
      code. Without the patch the syscall is prohibitive noisy for testing
      with trinity.
      Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
      Cc: Dave Jones <davej@codemonkey.org.uk>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      cc9e605d
    • Yannick Guerrini's avatar
      kernel/module.c: fix typos in message about unused symbols · 7b63c3ab
      Yannick Guerrini authored
      Fix typos in pr_warn message about unused symbols
      Signed-off-by: default avatarYannick Guerrini <yguerrini@tomshardware.fr>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      7b63c3ab
    • Peter Zijlstra's avatar
      lockdep: Fix the module unload key range freeing logic · 35a9393c
      Peter Zijlstra authored
      Module unload calls lockdep_free_key_range(), which removes entries
      from the data structures. Most of the lockdep code OTOH assumes the
      data structures are append only; in specific see the comments in
      add_lock_to_list() and look_up_lock_class().
      
      Clearly this has only worked by accident; make it work proper. The
      actual scenario to make it go boom would involve the memory freed by
      the module unlock being re-allocated and re-used for a lock inside of
      a rcu-sched grace period. This is a very unlikely scenario, still
      better plug the hole.
      
      Use RCU list iteration in all places and ammend the comments.
      
      Change lockdep_free_key_range() to issue a sync_sched() between
      removal from the lists and returning -- which results in the memory
      being freed. Further ensure the callers are placed correctly and
      comment the requirements.
      Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andrey Tsyvarev <tsyvarev@ispras.ru>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      35a9393c
  14. 12 Mar, 2015 1 commit
    • Andrey Ryabinin's avatar
      kasan, module, vmalloc: rework shadow allocation for modules · a5af5aa8
      Andrey Ryabinin authored
      Current approach in handling shadow memory for modules is broken.
      
      Shadow memory could be freed only after memory shadow corresponds it is no
      longer used.  vfree() called from interrupt context could use memory its
      freeing to store 'struct llist_node' in it:
      
          void vfree(const void *addr)
          {
          ...
              if (unlikely(in_interrupt())) {
                  struct vfree_deferred *p = this_cpu_ptr(&vfree_deferred);
                  if (llist_add((struct llist_node *)addr, &p->list))
                          schedule_work(&p->wq);
      
      Later this list node used in free_work() which actually frees memory.
      Currently module_memfree() called in interrupt context will free shadow
      before freeing module's memory which could provoke kernel crash.
      
      So shadow memory should be freed after module's memory.  However, such
      deallocation order could race with kasan_module_alloc() in module_alloc().
      
      Free shadow right before releasing vm area.  At this point vfree()'d
      memory is not used anymore and yet not available for other allocations.
      New VM_KASAN flag used to indicate that vm area has dynamically allocated
      shadow memory so kasan frees shadow only if it was previously allocated.
      Signed-off-by: default avatarAndrey Ryabinin <a.ryabinin@samsung.com>
      Acked-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a5af5aa8
  15. 06 Mar, 2015 1 commit
  16. 17 Feb, 2015 1 commit
  17. 13 Feb, 2015 1 commit
    • Andrey Ryabinin's avatar
      kasan: enable instrumentation of global variables · bebf56a1
      Andrey Ryabinin authored
      This feature let us to detect accesses out of bounds of global variables.
      This will work as for globals in kernel image, so for globals in modules.
      Currently this won't work for symbols in user-specified sections (e.g.
      __init, __read_mostly, ...)
      
      The idea of this is simple.  Compiler increases each global variable by
      redzone size and add constructors invoking __asan_register_globals()
      function.  Information about global variable (address, size, size with
      redzone ...) passed to __asan_register_globals() so we could poison
      variable's redzone.
      
      This patch also forces module_alloc() to return 8*PAGE_SIZE aligned
      address making shadow memory handling (
      kasan_module_alloc()/kasan_module_free() ) more simple.  Such alignment
      guarantees that each shadow page backing modules address space correspond
      to only one module_alloc() allocation.
      Signed-off-by: default avatarAndrey Ryabinin <a.ryabinin@samsung.com>
      Cc: Dmitry Vyukov <dvyukov@google.com>
      Cc: Konstantin Serebryany <kcc@google.com>
      Cc: Dmitry Chernenkov <dmitryc@google.com>
      Signed-off-by: default avatarAndrey Konovalov <adech.fo@gmail.com>
      Cc: Yuri Gribov <tetra2005@gmail.com>
      Cc: Konstantin Khlebnikov <koct9i@gmail.com>
      Cc: Sasha Levin <sasha.levin@oracle.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Cc: Christoph Lameter <cl@linux.com>
      Cc: Pekka Enberg <penberg@kernel.org>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      bebf56a1
  18. 10 Feb, 2015 2 commits
  19. 05 Feb, 2015 2 commits
  20. 21 Jan, 2015 1 commit
  21. 19 Jan, 2015 3 commits
    • Rusty Russell's avatar
      module: fix race in kallsyms resolution during module load success. · c7496379
      Rusty Russell authored
      The kallsyms routines (module_symbol_name, lookup_module_* etc) disable
      preemption to walk the modules rather than taking the module_mutex:
      this is because they are used for symbol resolution during oopses.
      
      This works because there are synchronize_sched() and synchronize_rcu()
      in the unload and failure paths.  However, there's one case which doesn't
      have that: the normal case where module loading succeeds, and we free
      the init section.
      
      We don't want a synchronize_rcu() there, because it would slow down
      module loading: this bug was introduced in 2009 to speed module
      loading in the first place.
      
      Thus, we want to do the free in an RCU callback.  We do this in the
      simplest possible way by allocating a new rcu_head: if we put it in
      the module structure we'd have to worry about that getting freed.
      Reported-by: default avatarRui Xiang <rui.xiang@huawei.com>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      c7496379
    • Rusty Russell's avatar
      module: remove mod arg from module_free, rename module_memfree(). · be1f221c
      Rusty Russell authored
      Nothing needs the module pointer any more, and the next patch will
      call it from RCU, where the module itself might no longer exist.
      Removing the arg is the safest approach.
      
      This just codifies the use of the module_alloc/module_free pattern
      which ftrace and bpf use.
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
      Cc: Mikael Starvik <starvik@axis.com>
      Cc: Jesper Nilsson <jesper.nilsson@axis.com>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Ley Foon Tan <lftan@altera.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Chris Metcalf <cmetcalf@ezchip.com>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: x86@kernel.org
      Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
      Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
      Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Cc: linux-cris-kernel@axis.com
      Cc: linux-kernel@vger.kernel.org
      Cc: linux-mips@linux-mips.org
      Cc: nios2-dev@lists.rocketboards.org
      Cc: linuxppc-dev@lists.ozlabs.org
      Cc: sparclinux@vger.kernel.org
      Cc: netdev@vger.kernel.org
      be1f221c
    • Rusty Russell's avatar
      module_arch_freeing_init(): new hook for archs before module->module_init freed. · d453cded
      Rusty Russell authored
      Archs have been abusing module_free() to clean up their arch-specific
      allocations.  Since module_free() is also (ab)used by BPF and trace code,
      let's keep it to simple allocations, and provide a hook called before
      that.
      
      This means that avr32, ia64, parisc and s390 no longer need to implement
      their own module_free() at all.  avr32 doesn't need module_finalize()
      either.
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      Cc: Chris Metcalf <cmetcalf@ezchip.com>
      Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
      Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Fenghua Yu <fenghua.yu@intel.com>
      Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
      Cc: Helge Deller <deller@gmx.de>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: linux-kernel@vger.kernel.org
      Cc: linux-ia64@vger.kernel.org
      Cc: linux-parisc@vger.kernel.org
      Cc: linux-s390@vger.kernel.org
      d453cded
  22. 10 Nov, 2014 2 commits
    • Ionut Alexa's avatar
      kernel:module Fix coding style errors and warnings. · 6da0b565
      Ionut Alexa authored
      Fixed codin style errors and warnings. Changes printk with
      print_debug/warn. Changed seq_printf to seq_puts.
      Signed-off-by: default avatarIonut Alexa <ionut.m.alexa@gmail.com>
      Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed bogus KERN_DEFAULT conversion)
      6da0b565
    • Masami Hiramatsu's avatar
      module: Remove stop_machine from module unloading · e513cc1c
      Masami Hiramatsu authored
      Remove stop_machine from module unloading by adding new reference
      counting algorithm.
      
      This atomic refcounter works like a semaphore, it can get (be
      incremented) only when the counter is not 0. When loading a module,
      kmodule subsystem sets the counter MODULE_REF_BASE (= 1). And when
      unloading the module, it subtracts MODULE_REF_BASE from the counter.
      If no one refers the module, the refcounter becomes 0 and we can
      remove the module safely. If someone referes it, we try to recover
      the counter by adding MODULE_REF_BASE unless the counter becomes 0,
      because the referrer can put the module right before recovering.
      If the recovering is failed, we can get the 0 refcount and it
      never be incremented again, it can be removed safely too.
      
      Note that __module_get() forcibly gets the module refcounter,
      users should use try_module_get() instead of that.
      Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
      Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
      e513cc1c