Commit Graph

396 Commits

Author SHA1 Message Date
Rusty Russell
d5db139ab3 module: make module_refcount() a signed integer.
James Bottomley points out that it will be -1 during unload.  It's
only used for diagnostics, so let's not hide that as it could be a
clue as to what's gone wrong.

Cc: Jason Wessel <jason.wessel@windriver.com>
Acked-and-documention-added-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Masami Hiramatsu <maasami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-01-22 11:15:54 +10:30
Rusty Russell
c749637909 module: fix race in kallsyms resolution during module load success.
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: Rui Xiang <rui.xiang@huawei.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2015-01-20 11:38:34 +10:30
Rusty Russell
be1f221c04 module: remove mod arg from module_free, rename module_memfree().
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: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Alexei 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
2015-01-20 11:38:33 +10:30
Rusty Russell
d453cded05 module_arch_freeing_init(): new hook for archs before module->module_init freed.
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: Rusty 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
2015-01-20 11:38:32 +10:30
Linus Torvalds
d790be3863 The exciting thing here is the getting rid of stop_machine on module
removal.  This is possible by using a simple atomic_t for the counter,
 rather than our fancy per-cpu counter: it turns out that no one is doing
 a module increment per net packet, so the slowdown should be in the noise.
 
 Also, script fixed for new git version.
 
 Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "The exciting thing here is the getting rid of stop_machine on module
  removal.  This is possible by using a simple atomic_t for the counter,
  rather than our fancy per-cpu counter: it turns out that no one is
  doing a module increment per net packet, so the slowdown should be in
  the noise"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  param: do not set store func without write perm
  params: cleanup sysfs allocation
  kernel:module Fix coding style errors and warnings.
  module: Remove stop_machine from module unloading
  module: Replace module_ref with atomic_t refcnt
  lib/bug: Use RCU list ops for module_bug_list
  module: Unlink module with RCU synchronizing instead of stop_machine
  module: Wait for RCU synchronizing before releasing a module
2014-12-18 20:55:41 -08:00
Ionut Alexa
6da0b56515 kernel:module Fix coding style errors and warnings.
Fixed codin style errors and warnings. Changes printk with
print_debug/warn. Changed seq_printf to seq_puts.

Signed-off-by: Ionut Alexa <ionut.m.alexa@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed bogus KERN_DEFAULT conversion)
2014-11-11 17:07:47 +10:30
Masami Hiramatsu
e513cc1c07 module: Remove stop_machine from module unloading
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: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-11-11 17:07:46 +10:30
Masami Hiramatsu
2f35c41f58 module: Replace module_ref with atomic_t refcnt
Replace module_ref per-cpu complex reference counter with
an atomic_t simple refcnt. This is for code simplification.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-11-11 17:07:46 +10:30
Masami Hiramatsu
0286b5ea12 lib/bug: Use RCU list ops for module_bug_list
Actually since module_bug_list should be used in BUG context,
we may not need this. But for someone who want to use this
from normal context, this makes module_bug_list an RCU list.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-11-11 17:07:46 +10:30
Masami Hiramatsu
461e34aed0 module: Unlink module with RCU synchronizing instead of stop_machine
Unlink module from module list with RCU synchronizing instead
of using stop_machine(). Since module list is already protected
by rcu, we don't need stop_machine() anymore.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-11-11 17:07:45 +10:30
Masami Hiramatsu
4f48795b61 module: Wait for RCU synchronizing before releasing a module
Wait for RCU synchronizing on failure path of module loading
before releasing struct module, because the memory of mod->list
can still be accessed by list walkers (e.g. kallsyms).

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-11-11 17:07:44 +10:30
Peter Zijlstra
3c9b2c3d64 sched, modules: Fix nested sleep in add_unformed_module()
This is a genuine bug in add_unformed_module(), we cannot use blocking
primitives inside a wait loop.

So rewrite the wait_event_interruptible() usage to use the fresh
wait_woken() stuff.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: tglx@linutronix.de
Cc: ilya.dryomov@inktank.com
Cc: umgwanakikbuti@gmail.com
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: oleg@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: http://lkml.kernel.org/r/20140924082242.458562904@infradead.org
[ So this is probably complex to backport and the race wasn't reported AFAIK,
  so not marked for -stable. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-10-28 10:56:30 +01:00
Linus Torvalds
50edb5cc22 A single panic fix for a rare race, stable CC'd.
Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module fix from Rusty Russell:
 "A single panic fix for a rare race, stable CC'd"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  modules, lock around setting of MODULE_STATE_UNFORMED
2014-10-18 10:24:26 -07:00
Prarit Bhargava
d3051b489a modules, lock around setting of MODULE_STATE_UNFORMED
A panic was seen in the following sitation.

There are two threads running on the system. The first thread is a system
monitoring thread that is reading /proc/modules. The second thread is
loading and unloading a module (in this example I'm using my simple
dummy-module.ko).  Note, in the "real world" this occurred with the qlogic
driver module.

When doing this, the following panic occurred:

 ------------[ cut here ]------------
 kernel BUG at kernel/module.c:3739!
 invalid opcode: 0000 [#1] SMP
 Modules linked in: binfmt_misc sg nfsv3 rpcsec_gss_krb5 nfsv4 dns_resolver nfs fscache intel_powerclamp coretemp kvm_intel kvm crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel lrw igb gf128mul glue_helper iTCO_wdt iTCO_vendor_support ablk_helper ptp sb_edac cryptd pps_core edac_core shpchp i2c_i801 pcspkr wmi lpc_ich ioatdma mfd_core dca ipmi_si nfsd ipmi_msghandler auth_rpcgss nfs_acl lockd sunrpc xfs libcrc32c sr_mod cdrom sd_mod crc_t10dif crct10dif_common mgag200 syscopyarea sysfillrect sysimgblt i2c_algo_bit drm_kms_helper ttm isci drm libsas ahci libahci scsi_transport_sas libata i2c_core dm_mirror dm_region_hash dm_log dm_mod [last unloaded: dummy_module]
 CPU: 37 PID: 186343 Comm: cat Tainted: GF          O--------------   3.10.0+ #7
 Hardware name: Intel Corporation S2600CP/S2600CP, BIOS RMLSDP.86I.00.29.D696.1311111329 11/11/2013
 task: ffff8807fd2d8000 ti: ffff88080fa7c000 task.ti: ffff88080fa7c000
 RIP: 0010:[<ffffffff810d64c5>]  [<ffffffff810d64c5>] module_flags+0xb5/0xc0
 RSP: 0018:ffff88080fa7fe18  EFLAGS: 00010246
 RAX: 0000000000000003 RBX: ffffffffa03b5200 RCX: 0000000000000000
 RDX: 0000000000001000 RSI: ffff88080fa7fe38 RDI: ffffffffa03b5000
 RBP: ffff88080fa7fe28 R08: 0000000000000010 R09: 0000000000000000
 R10: 0000000000000000 R11: 000000000000000f R12: ffffffffa03b5000
 R13: ffffffffa03b5008 R14: ffffffffa03b5200 R15: ffffffffa03b5000
 FS:  00007f6ae57ef740(0000) GS:ffff88101e7a0000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000404f70 CR3: 0000000ffed48000 CR4: 00000000001407e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
 Stack:
  ffffffffa03b5200 ffff8810101e4800 ffff88080fa7fe70 ffffffff810d666c
  ffff88081e807300 000000002e0f2fbf 0000000000000000 ffff88100f257b00
  ffffffffa03b5008 ffff88080fa7ff48 ffff8810101e4800 ffff88080fa7fee0
 Call Trace:
  [<ffffffff810d666c>] m_show+0x19c/0x1e0
  [<ffffffff811e4d7e>] seq_read+0x16e/0x3b0
  [<ffffffff812281ed>] proc_reg_read+0x3d/0x80
  [<ffffffff811c0f2c>] vfs_read+0x9c/0x170
  [<ffffffff811c1a58>] SyS_read+0x58/0xb0
  [<ffffffff81605829>] system_call_fastpath+0x16/0x1b
 Code: 48 63 c2 83 c2 01 c6 04 03 29 48 63 d2 eb d9 0f 1f 80 00 00 00 00 48 63 d2 c6 04 13 2d 41 8b 0c 24 8d 50 02 83 f9 01 75 b2 eb cb <0f> 0b 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41
 RIP  [<ffffffff810d64c5>] module_flags+0xb5/0xc0
  RSP <ffff88080fa7fe18>

    Consider the two processes running on the system.

    CPU 0 (/proc/modules reader)
    CPU 1 (loading/unloading module)

    CPU 0 opens /proc/modules, and starts displaying data for each module by
    traversing the modules list via fs/seq_file.c:seq_open() and
    fs/seq_file.c:seq_read().  For each module in the modules list, seq_read
    does

            op->start()  <-- this is a pointer to m_start()
            op->show()   <- this is a pointer to m_show()
            op->stop()   <-- this is a pointer to m_stop()

    The m_start(), m_show(), and m_stop() module functions are defined in
    kernel/module.c. The m_start() and m_stop() functions acquire and release
    the module_mutex respectively.

    ie) When reading /proc/modules, the module_mutex is acquired and released
    for each module.

    m_show() is called with the module_mutex held.  It accesses the module
    struct data and attempts to write out module data.  It is in this code
    path that the above BUG_ON() warning is encountered, specifically m_show()
    calls

    static char *module_flags(struct module *mod, char *buf)
    {
            int bx = 0;

            BUG_ON(mod->state == MODULE_STATE_UNFORMED);
    ...

    The other thread, CPU 1, in unloading the module calls the syscall
    delete_module() defined in kernel/module.c.  The module_mutex is acquired
    for a short time, and then released.  free_module() is called without the
    module_mutex.  free_module() then sets mod->state = MODULE_STATE_UNFORMED,
    also without the module_mutex.  Some additional code is called and then the
    module_mutex is reacquired to remove the module from the modules list:

        /* Now we can delete it from the lists */
        mutex_lock(&module_mutex);
        stop_machine(__unlink_module, mod, NULL);
        mutex_unlock(&module_mutex);

This is the sequence of events that leads to the panic.

CPU 1 is removing dummy_module via delete_module().  It acquires the
module_mutex, and then releases it.  CPU 1 has NOT set dummy_module->state to
MODULE_STATE_UNFORMED yet.

CPU 0, which is reading the /proc/modules, acquires the module_mutex and
acquires a pointer to the dummy_module which is still in the modules list.
CPU 0 calls m_show for dummy_module.  The check in m_show() for
MODULE_STATE_UNFORMED passed for dummy_module even though it is being
torn down.

Meanwhile CPU 1, which has been continuing to remove dummy_module without
holding the module_mutex, now calls free_module() and sets
dummy_module->state to MODULE_STATE_UNFORMED.

CPU 0 now calls module_flags() with dummy_module and ...

static char *module_flags(struct module *mod, char *buf)
{
        int bx = 0;

        BUG_ON(mod->state == MODULE_STATE_UNFORMED);

and BOOM.

Acquire and release the module_mutex lock around the setting of
MODULE_STATE_UNFORMED in the teardown path, which should resolve the
problem.

Testing: In the unpatched kernel I can panic the system within 1 minute by
doing

while (true) do insmod dummy_module.ko; rmmod dummy_module.ko; done

and

while (true) do cat /proc/modules; done

in separate terminals.

In the patched kernel I was able to run just over one hour without seeing
any issues.  I also verified the output of panic via sysrq-c and the output
of /proc/modules looks correct for all three states for the dummy_module.

        dummy_module 12661 0 - Unloading 0xffffffffa03a5000 (OE-)
        dummy_module 12661 0 - Live 0xffffffffa03bb000 (OE)
        dummy_module 14015 1 - Loading 0xffffffffa03a5000 (OE+)

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@kernel.org
2014-10-15 10:20:09 +10:30
Linus Torvalds
6325e940e7 arm64 updates for 3.18:
- eBPF JIT compiler for arm64
 - CPU suspend backend for PSCI (firmware interface) with standard idle
   states defined in DT (generic idle driver to be merged via a different
   tree)
 - Support for CONFIG_DEBUG_SET_MODULE_RONX
 - Support for unmapped cpu-release-addr (outside kernel linear mapping)
 - set_arch_dma_coherent_ops() implemented and bus notifiers removed
 - EFI_STUB improvements when base of DRAM is occupied
 - Typos in KGDB macros
 - Clean-up to (partially) allow kernel building with LLVM
 - Other clean-ups (extern keyword, phys_addr_t usage)
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Catalin Marinas:
 - eBPF JIT compiler for arm64
 - CPU suspend backend for PSCI (firmware interface) with standard idle
   states defined in DT (generic idle driver to be merged via a
   different tree)
 - Support for CONFIG_DEBUG_SET_MODULE_RONX
 - Support for unmapped cpu-release-addr (outside kernel linear mapping)
 - set_arch_dma_coherent_ops() implemented and bus notifiers removed
 - EFI_STUB improvements when base of DRAM is occupied
 - Typos in KGDB macros
 - Clean-up to (partially) allow kernel building with LLVM
 - Other clean-ups (extern keyword, phys_addr_t usage)

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (51 commits)
  arm64: Remove unneeded extern keyword
  ARM64: make of_device_ids const
  arm64: Use phys_addr_t type for physical address
  aarch64: filter $x from kallsyms
  arm64: Use DMA_ERROR_CODE to denote failed allocation
  arm64: Fix typos in KGDB macros
  arm64: insn: Add return statements after BUG_ON()
  arm64: debug: don't re-enable debug exceptions on return from el1_dbg
  Revert "arm64: dmi: Add SMBIOS/DMI support"
  arm64: Implement set_arch_dma_coherent_ops() to replace bus notifiers
  of: amba: use of_dma_configure for AMBA devices
  arm64: dmi: Add SMBIOS/DMI support
  arm64: Correct ftrace calls to aarch64_insn_gen_branch_imm()
  arm64:mm: initialize max_mapnr using function set_max_mapnr
  setup: Move unmask of async interrupts after possible earlycon setup
  arm64: LLVMLinux: Fix inline arm64 assembly for use with clang
  arm64: pageattr: Correctly adjust unaligned start addresses
  net: bpf: arm64: fix module memory leak when JIT image build fails
  arm64: add PSCI CPU_SUSPEND based cpu_suspend support
  arm64: kernel: introduce cpu_init_idle CPU operation
  ...
2014-10-08 05:34:24 -04:00
Kyle McMartin
6c34f1f542 aarch64: filter $x from kallsyms
Similar to ARM, AArch64 is generating $x and $d syms... which isn't
terribly helpful when looking at %pF output and the like. Filter those
out in kallsyms, modpost and when looking at module symbols.

Seems simplest since none of these check EM_ARM anyway, to just add it
to the strchr used, rather than trying to make things overly
complicated.

initcall_debug improves:
dmesg_before.txt: initcall $x+0x0/0x154 [sg] returned 0 after 26331 usecs
dmesg_after.txt: initcall init_sg+0x0/0x154 [sg] returned 0 after 15461 usecs

Signed-off-by: Kyle McMartin <kyle@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-10-02 17:01:51 +01:00
Jani Nikula
6a4c264313 module: rename KERNEL_PARAM_FL_NOARG to avoid confusion
Make it clear this is about kernel_param_ops, not kernel_param (which
will soon have a flags field of its own). No functional changes.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Jon Mason <jon.mason@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-08-27 21:54:07 +09:30
Andy Lutomirski
ff7e0055bb module: Clean up ro/nx after early module load failures
The commit

    4982223e51 module: set nx before marking module MODULE_STATE_COMING.

introduced a regression: if a module fails to parse its arguments or
if mod_sysfs_setup fails, then the module's memory will be freed
while still read-only.  Anything that reuses that memory will crash
as soon as it tries to write to it.

Cc: stable@vger.kernel.org # v3.16
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-08-16 04:47:00 +09:30
Linus Torvalds
c8d6637d04 This finally applies the stricter sysfs perms checking we pulled out
before last merge window.  A few stragglers are fixed (thanks linux-next!)
 
 Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "This finally applies the stricter sysfs perms checking we pulled out
  before last merge window.  A few stragglers are fixed (thanks
  linux-next!)"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  arch/powerpc/platforms/powernv/opal-dump.c: fix world-writable sysfs files
  arch/powerpc/platforms/powernv/opal-elog.c: fix world-writable sysfs files
  drivers/video/fbdev/s3c2410fb.c: don't make debug world-writable.
  ARM: avoid ARM binutils leaking ELF local symbols
  scripts: modpost: Remove numeric suffix pattern matching
  scripts: modpost: fix compilation warning
  sysfs: disallow world-writable files.
  module: return bool from within_module*()
  module: add within_module() function
  modules: Fix build error in moduleloader.h
2014-08-10 21:31:58 -07:00
Russell King
2e3a10a155 ARM: avoid ARM binutils leaking ELF local symbols
Symbols starting with .L are ELF local symbols and should not appear
in ELF symbol tables.  However, unfortunately ARM binutils leaks the
.LANCHOR symbols into the symbol table, which leads kallsyms to report
these symbols rather than the real name.  It is not very useful when
%pf reports symbols against these leaked .LANCHOR symbols.

Arrange for kallsyms to ignore these symbols using the same mechanism
that is used for the ARM mapping symbols.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-07-27 20:52:47 +09:30
Petr Mladek
9b20a352d7 module: add within_module() function
It is just a small optimization that allows to replace few
occurrences of within_module_init() || within_module_core()
with a single call.

Signed-off-by: Petr Mladek <pmladek@suse.cz>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-07-27 20:52:43 +09:30
Jarod Wilson
002c77a48b crypto: fips - only panic on bad/missing crypto mod signatures
Per further discussion with NIST, the requirements for FIPS state that
we only need to panic the system on failed kernel module signature checks
for crypto subsystem modules. This moves the fips-mode-only module
signature check out of the generic module loading code, into the crypto
subsystem, at points where we can catch both algorithm module loads and
mode module loads. At the same time, make CONFIG_CRYPTO_FIPS dependent on
CONFIG_MODULE_SIG, as this is entirely necessary for FIPS mode.

v2: remove extraneous blank line, perform checks in static inline
function, drop no longer necessary fips.h include.

CC: "David S. Miller" <davem@davemloft.net>
CC: Rusty Russell <rusty@rustcorp.com.au>
CC: Stephan Mueller <stephan.mueller@atsec.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-07-03 21:38:32 +08:00
Linus Torvalds
4251c2a670 Most of this is cleaning up various driver sysfs permissions so we can
re-add the perm check (we unified the module param and sysfs checks, but
 the module ones were stronger so we weakened them temporarily).
 
 Param parsing gets documented, and also "--" now forces args to be
 handed to init (and ignored by the kernel).
 
 Module NX/RO protections get tightened: we now set them before calling
 parse_args().
 
 Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Most of this is cleaning up various driver sysfs permissions so we can
  re-add the perm check (we unified the module param and sysfs checks,
  but the module ones were stronger so we weakened them temporarily).

  Param parsing gets documented, and also "--" now forces args to be
  handed to init (and ignored by the kernel).

  Module NX/RO protections get tightened: we now set them before calling
  parse_args()"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  module: set nx before marking module MODULE_STATE_COMING.
  samples/kobject/: avoid world-writable sysfs files.
  drivers/hid/hid-picolcd_fb: avoid world-writable sysfs files.
  drivers/staging/speakup/: avoid world-writable sysfs files.
  drivers/regulator/virtual: avoid world-writable sysfs files.
  drivers/scsi/pm8001/pm8001_ctl.c: avoid world-writable sysfs files.
  drivers/hid/hid-lg4ff.c: avoid world-writable sysfs files.
  drivers/video/fbdev/sm501fb.c: avoid world-writable sysfs files.
  drivers/mtd/devices/docg3.c: avoid world-writable sysfs files.
  speakup: fix incorrect perms on speakup_acntsa.c
  cpumask.h: silence warning with -Wsign-compare
  Documentation: Update kernel-parameters.tx
  param: hand arguments after -- straight to init
  modpost: Fix resource leak in read_dump()
2014-06-11 16:09:14 -07:00
Rusty Russell
4982223e51 module: set nx before marking module MODULE_STATE_COMING.
We currently set RO & NX on modules very late: after we move them from
MODULE_STATE_UNFORMED to MODULE_STATE_COMING, and after we call
parse_args() (which can exec code in the module).

Much better is to do it in complete_formation() and then call
the notifier.

This means that the notifiers will be called on a module which
is already RO & NX, so that may cause problems (ftrace already
changed so they're unaffected).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-05-14 10:55:47 +09:30
Linus Torvalds
60b88f3941 Fixed one missing place for the new taint flag, and remove a warning
giving only false positives (now we finally figured out why).
 
 Cheers,
 Rusty.
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Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module fixes from Rusty Russell:
 "Fixed one missing place for the new taint flag, and remove a warning
  giving only false positives (now we finally figured out why)"

* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  module: remove warning about waiting module removal.
  Fix: tracing: use 'E' instead of 'X' for unsigned module taint flag
2014-05-01 10:35:01 -07:00
Steven Rostedt (Red Hat)
a949ae560a ftrace/module: Hardcode ftrace_module_init() call into load_module()
A race exists between module loading and enabling of function tracer.

	CPU 1				CPU 2
	-----				-----
  load_module()
   module->state = MODULE_STATE_COMING

				register_ftrace_function()
				 mutex_lock(&ftrace_lock);
				 ftrace_startup()
				  update_ftrace_function();
				   ftrace_arch_code_modify_prepare()
				    set_all_module_text_rw();
				   <enables-ftrace>
				    ftrace_arch_code_modify_post_process()
				     set_all_module_text_ro();

				[ here all module text is set to RO,
				  including the module that is
				  loading!! ]

   blocking_notifier_call_chain(MODULE_STATE_COMING);
    ftrace_init_module()

     [ tries to modify code, but it's RO, and fails!
       ftrace_bug() is called]

When this race happens, ftrace_bug() will produces a nasty warning and
all of the function tracing features will be disabled until reboot.

The simple solution is to treate module load the same way the core
kernel is treated at boot. To hardcode the ftrace function modification
of converting calls to mcount into nops. This is done in init/main.c
there's no reason it could not be done in load_module(). This gives
a better control of the changes and doesn't tie the state of the
module to its notifiers as much. Ftrace is special, it needs to be
treated as such.

The reason this would work, is that the ftrace_module_init() would be
called while the module is in MODULE_STATE_UNFORMED, which is ignored
by the set_all_module_text_ro() call.

Link: http://lkml.kernel.org/r/1395637826-3312-1-git-send-email-indou.takao@jp.fujitsu.com

Reported-by: Takao Indoh <indou.takao@jp.fujitsu.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: stable@vger.kernel.org # 2.6.38+
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-28 10:37:21 -04:00
Rusty Russell
51e158c12a param: hand arguments after -- straight to init
The kernel passes any args it doesn't need through to init, except it
assumes anything containing '.' belongs to the kernel (for a module).
This change means all users can clearly distinguish which arguments
are for init.

For example, the kernel uses debug ("dee-bug") to mean log everything to
the console, where systemd uses the debug from the Scandinavian "day-boog"
meaning "fail to boot".  If a future versions uses argv[] instead of
reading /proc/cmdline, this confusion will be avoided.

eg: test 'FOO="this is --foo"' -- 'systemd.debug="true true true"'

Gives:
argv[0] = '/debug-init'
argv[1] = 'test'
argv[2] = 'systemd.debug=true true true'
envp[0] = 'HOME=/'
envp[1] = 'TERM=linux'
envp[2] = 'FOO=this is --foo'

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-28 11:48:34 +09:30
Rusty Russell
79465d2fd4 module: remove warning about waiting module removal.
We remove the waiting module removal in commit 3f2b9c9cdf (September
2013), but it turns out that modprobe in kmod (< version 16) was
asking for waiting module removal.  No one noticed since modprobe would
check for 0 usage immediately before trying to remove the module, and
the race is unlikely.

However, it means that anyone running old (but not ancient) kmod
versions is hitting the printk designed to see if anyone was running
"rmmod -w".  All reports so far have been false positives, so remove
the warning.

Fixes: 3f2b9c9cdf
Reported-by: Valerio Vanni <valerio.vanni@inwind.it>
Cc: Elliott, Robert (Server Storage) <Elliott@hp.com>
Cc: stable@kernel.org
Acked-by: Lucas De Marchi <lucas.de.marchi@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-04-28 11:06:59 +09:30
Christoph Lameter
08f141d3db modules: use raw_cpu_write for initialization of per cpu refcount.
The initialization of a structure is not subject to synchronization.
The use of __this_cpu would trigger a false positive with the additional
preemption checks for __this_cpu ops.

So simply disable the check through the use of raw_cpu ops.

Trace:

  __this_cpu_write operation in preemptible [00000000] code: modprobe/286
  caller is __this_cpu_preempt_check+0x38/0x60
  CPU: 3 PID: 286 Comm: modprobe Tainted: GF            3.12.0-rc4+ #187
  Call Trace:
    dump_stack+0x4e/0x82
    check_preemption_disabled+0xec/0x110
    __this_cpu_preempt_check+0x38/0x60
    load_module+0xcfd/0x2650
    SyS_init_module+0xa6/0xd0
    tracesys+0xe1/0xe6

Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-04-07 16:36:14 -07:00
Linus Torvalds
6f4c98e1c2 Nothing major: the stricter permissions checking for sysfs broke
a staging driver; fix included.  Greg KH said he'd take the patch
 but hadn't as the merge window opened, so it's included here
 to avoid breaking build.
 
 Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Nothing major: the stricter permissions checking for sysfs broke a
  staging driver; fix included.  Greg KH said he'd take the patch but
  hadn't as the merge window opened, so it's included here to avoid
  breaking build"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  staging: fix up speakup kobject mode
  Use 'E' instead of 'X' for unsigned module taint flag.
  VERIFY_OCTAL_PERMISSIONS: stricter checking for sysfs perms.
  kallsyms: fix percpu vars on x86-64 with relocation.
  kallsyms: generalize address range checking
  module: LLVMLinux: Remove unused function warning from __param_check macro
  Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE
  module: remove MODULE_GENERIC_TABLE
  module: allow multiple calls to MODULE_DEVICE_TABLE() per module
  module: use pr_cont
2014-04-06 09:38:07 -07:00
Linus Torvalds
176ab02d49 Merge branch 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 LTO changes from Peter Anvin:
 "More infrastructure work in preparation for link-time optimization
  (LTO).  Most of these changes is to make sure symbols accessed from
  assembly code are properly marked as visible so the linker doesn't
  remove them.

  My understanding is that the changes to support LTO are still not
  upstream in binutils, but are on the way there.  This patchset should
  conclude the x86-specific changes, and remaining patches to actually
  enable LTO will be fed through the Kbuild tree (other than keeping up
  with changes to the x86 code base, of course), although not
  necessarily in this merge window"

* 'x86-asmlinkage-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (25 commits)
  Kbuild, lto: Handle basic LTO in modpost
  Kbuild, lto: Disable LTO for asm-offsets.c
  Kbuild, lto: Add a gcc-ld script to let run gcc as ld
  Kbuild, lto: add ld-version and ld-ifversion macros
  Kbuild, lto: Drop .number postfixes in modpost
  Kbuild, lto, workaround: Don't warn for initcall_reference in modpost
  lto: Disable LTO for sys_ni
  lto: Handle LTO common symbols in module loader
  lto, workaround: Add workaround for initcall reordering
  lto: Make asmlinkage __visible
  x86, lto: Disable LTO for the x86 VDSO
  initconst, x86: Fix initconst mistake in ts5500 code
  initconst: Fix initconst mistake in dcdbas
  asmlinkage: Make trace_hardirqs_on/off_caller visible
  asmlinkage, x86: Fix 32bit memcpy for LTO
  asmlinkage Make __stack_chk_failed and memcmp visible
  asmlinkage: Mark rwsem functions that can be called from assembler asmlinkage
  asmlinkage: Make main_extable_sort_needed visible
  asmlinkage, mutex: Mark __visible
  asmlinkage: Make trace_hardirq visible
  ...
2014-03-31 14:13:25 -07:00
Rusty Russell
57673c2b0b Use 'E' instead of 'X' for unsigned module taint flag.
Takashi Iwai <tiwai@suse.de> says:
> The letter 'X' has been already used for SUSE kernels for very long
> time, to indicate the external supported modules.  Can the new flag be
> changed to another letter for avoiding conflict...?
> (BTW, we also use 'N' for "no support", too.)

Note: this code should be cleaned up, so we don't have such maps in
three places!

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-03-31 14:52:43 +10:30
Dave Jones
8c90487cdc Rename TAINT_UNSAFE_SMP to TAINT_CPU_OUT_OF_SPEC
Rename TAINT_UNSAFE_SMP to TAINT_CPU_OUT_OF_SPEC, so we can repurpose
the flag to encompass a wider range of pushing the CPU beyond its
warrany.

Signed-off-by: Dave Jones <davej@fedoraproject.org>
Link: http://lkml.kernel.org/r/20140226154949.GA770@redhat.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2014-03-20 16:28:09 -07:00
Mathieu Desnoyers
66cc69e34e Fix: module signature vs tracepoints: add new TAINT_UNSIGNED_MODULE
Users have reported being unable to trace non-signed modules loaded
within a kernel supporting module signature.

This is caused by tracepoint.c:tracepoint_module_coming() refusing to
take into account tracepoints sitting within force-loaded modules
(TAINT_FORCED_MODULE). The reason for this check, in the first place, is
that a force-loaded module may have a struct module incompatible with
the layout expected by the kernel, and can thus cause a kernel crash
upon forced load of that module on a kernel with CONFIG_TRACEPOINTS=y.

Tracepoints, however, specifically accept TAINT_OOT_MODULE and
TAINT_CRAP, since those modules do not lead to the "very likely system
crash" issue cited above for force-loaded modules.

With kernels having CONFIG_MODULE_SIG=y (signed modules), a non-signed
module is tainted re-using the TAINT_FORCED_MODULE taint flag.
Unfortunately, this means that Tracepoints treat that module as a
force-loaded module, and thus silently refuse to consider any tracepoint
within this module.

Since an unsigned module does not fit within the "very likely system
crash" category of tainting, add a new TAINT_UNSIGNED_MODULE taint flag
to specifically address this taint behavior, and accept those modules
within Tracepoints. We use the letter 'X' as a taint flag character for
a module being loaded that doesn't know how to sign its name (proposed
by Steven Rostedt).

Also add the missing 'O' entry to trace event show_module_flags() list
for the sake of completeness.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
NAKed-by: Ingo Molnar <mingo@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: David Howells <dhowells@redhat.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-03-13 12:11:51 +10:30
Jiri Slaby
27bba4d6bb module: use pr_cont
When dumping loaded modules, we print them one by one in separate
printks. Let's use pr_cont as they are continuation prints.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-03-13 12:10:59 +10:30
Joe Mario
80375980f1 lto: Handle LTO common symbols in module loader
Here is the workaround I made for having the kernel not reject modules
built with -flto.  The clean solution would be to get the compiler to not
emit the symbol.  Or if it has to emit the symbol, then emit it as
initialized data but put it into a comdat/linkonce section.

Minor tweaks by AK over Joe's patch.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1391846481-31491-5-git-send-email-ak@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2014-02-13 20:24:50 -08:00
Tetsuo Handa
22e669568d module: Add missing newline in printk call.
Add missing \n and also follow commit bddb12b3 "kernel/module.c: use pr_foo()".

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-01-21 09:59:16 +10:30
Linus Torvalds
ce6513f758 Mainly boring here, too. rmmod --wait finally removed, though.
Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Mainly boring here, too.  rmmod --wait finally removed, though"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  modpost: fix bogus 'exported twice' warnings.
  init: fix in-place parameter modification regression
  asmlinkage, module: Make ksymtab and kcrctab symbols and __this_module __visible
  kernel: add support for init_array constructors
  modpost: Optionally ignore secondary errors seen if a single module build fails
  module: remove rmmod --wait option.
2013-11-15 13:27:50 +09:00
Andrew Morton
bddb12b32f kernel/module.c: use pr_foo()
kernel/module.c uses a mix of printk(KERN_foo and pr_foo().  Convert it
all to pr_foo and make the offered cleanups.

Not sure what to do about the printk(KERN_DEFAULT).  We don't have a
pr_default().

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Joe Perches <joe@perches.com>
Cc: Frantisek Hrbata <fhrbata@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-11-13 12:09:34 +09:00
Frantisek Hrbata
eb3057df73 kernel: add support for init_array constructors
This adds the .init_array section as yet another section with constructors. This
is needed because gcc could add __gcov_init calls to .init_array or .ctors
section, depending on gcc (and binutils) version .

v2: - reuse mod->ctors for .init_array section for modules, because gcc uses
      .ctors or .init_array, but not both at the same time
v3: - fail to load if that does happen somehow.

Signed-off-by: Frantisek Hrbata <fhrbata@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-10-17 15:05:17 +10:30
Rusty Russell
3f2b9c9cdf module: remove rmmod --wait option.
The option to wait for a module reference count to reach zero was in
the initial module implementation, but it was never supported in
modprobe (you had to use rmmod --wait).  After discussion with Lucas,
It has been deprecated (with a 10 second sleep) in kmod for the last
year.

This finally removes it: the flag will evoke a printk warning and a
normal (non-blocking) remove attempt.

Cc: Lucas De Marchi <lucas.de.marchi@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-09-23 15:44:58 +09:30
Linus Torvalds
45d9a2220f Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs pile 1 from Al Viro:
 "Unfortunately, this merge window it'll have a be a lot of small piles -
  my fault, actually, for not keeping #for-next in anything that would
  resemble a sane shape ;-/

  This pile: assorted fixes (the first 3 are -stable fodder, IMO) and
  cleanups + %pd/%pD formats (dentry/file pathname, up to 4 last
  components) + several long-standing patches from various folks.

  There definitely will be a lot more (starting with Miklos'
  check_submount_and_drop() series)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
  direct-io: Handle O_(D)SYNC AIO
  direct-io: Implement generic deferred AIO completions
  add formats for dentry/file pathnames
  kvm eventfd: switch to fdget
  powerpc kvm: use fdget
  switch fchmod() to fdget
  switch epoll_ctl() to fdget
  switch copy_module_from_fd() to fdget
  git simplify nilfs check for busy subtree
  ibmasmfs: don't bother passing superblock when not needed
  don't pass superblock to hypfs_{mkdir,create*}
  don't pass superblock to hypfs_diag_create_files
  don't pass superblock to hypfs_vm_create_files()
  oprofile: get rid of pointless forward declarations of struct super_block
  oprofilefs_create_...() do not need superblock argument
  oprofilefs_mkdir() doesn't need superblock argument
  don't bother with passing superblock to oprofile_create_stats_files()
  oprofile: don't bother with passing superblock to ->create_files()
  don't bother passing sb to oprofile_create_files()
  coh901318: don't open-code simple_read_from_buffer()
  ...
2013-09-05 08:50:26 -07:00
Al Viro
a2e0578be3 switch copy_module_from_fd() to fdget
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-09-03 23:04:44 -04:00
Li Zhong
942e443127 module: Fix mod->mkobj.kobj potentially freed too early
DEBUG_KOBJECT_RELEASE helps to find the issue attached below.

After some investigation, it seems the reason is:
The mod->mkobj.kobj(ffffffffa01600d0 below) is freed together with mod
itself in free_module(). However, its children still hold references to
it, as the delay caused by DEBUG_KOBJECT_RELEASE. So when the
child(holders below) tries to decrease the reference count to its parent
in kobject_del(), BUG happens as it tries to access already freed memory.

This patch tries to fix it by waiting for the mod->mkobj.kobj to be
really released in the module removing process (and some error code
paths).

[ 1844.175287] kobject: 'holders' (ffff88007c1f1600): kobject_release, parent ffffffffa01600d0 (delayed)
[ 1844.178991] kobject: 'notes' (ffff8800370b2a00): kobject_release, parent ffffffffa01600d0 (delayed)
[ 1845.180118] kobject: 'holders' (ffff88007c1f1600): kobject_cleanup, parent ffffffffa01600d0
[ 1845.182130] kobject: 'holders' (ffff88007c1f1600): auto cleanup kobject_del
[ 1845.184120] BUG: unable to handle kernel paging request at ffffffffa01601d0
[ 1845.185026] IP: [<ffffffff812cda81>] kobject_put+0x11/0x60
[ 1845.185026] PGD 1a13067 PUD 1a14063 PMD 7bd30067 PTE 0
[ 1845.185026] Oops: 0000 [#1] PREEMPT
[ 1845.185026] Modules linked in: xfs libcrc32c [last unloaded: kprobe_example]
[ 1845.185026] CPU: 0 PID: 18 Comm: kworker/0:1 Tainted: G           O 3.11.0-rc6-next-20130819+ #1
[ 1845.185026] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[ 1845.185026] Workqueue: events kobject_delayed_cleanup
[ 1845.185026] task: ffff88007ca51f00 ti: ffff88007ca5c000 task.ti: ffff88007ca5c000
[ 1845.185026] RIP: 0010:[<ffffffff812cda81>]  [<ffffffff812cda81>] kobject_put+0x11/0x60
[ 1845.185026] RSP: 0018:ffff88007ca5dd08  EFLAGS: 00010282
[ 1845.185026] RAX: 0000000000002000 RBX: ffffffffa01600d0 RCX: ffffffff8177d638
[ 1845.185026] RDX: ffff88007ca5dc18 RSI: 0000000000000000 RDI: ffffffffa01600d0
[ 1845.185026] RBP: ffff88007ca5dd18 R08: ffffffff824e9810 R09: ffffffffffffffff
[ 1845.185026] R10: ffff8800ffffffff R11: dead4ead00000001 R12: ffffffff81a95040
[ 1845.185026] R13: ffff88007b27a960 R14: ffff88007c1f1600 R15: 0000000000000000
[ 1845.185026] FS:  0000000000000000(0000) GS:ffffffff81a23000(0000) knlGS:0000000000000000
[ 1845.185026] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 1845.185026] CR2: ffffffffa01601d0 CR3: 0000000037207000 CR4: 00000000000006b0
[ 1845.185026] Stack:
[ 1845.185026]  ffff88007c1f1600 ffff88007c1f1600 ffff88007ca5dd38 ffffffff812cdb7e
[ 1845.185026]  0000000000000000 ffff88007c1f1640 ffff88007ca5dd68 ffffffff812cdbfe
[ 1845.185026]  ffff88007c974800 ffff88007c1f1640 ffff88007ff61a00 0000000000000000
[ 1845.185026] Call Trace:
[ 1845.185026]  [<ffffffff812cdb7e>] kobject_del+0x2e/0x40
[ 1845.185026]  [<ffffffff812cdbfe>] kobject_delayed_cleanup+0x6e/0x1d0
[ 1845.185026]  [<ffffffff81063a45>] process_one_work+0x1e5/0x670
[ 1845.185026]  [<ffffffff810639e3>] ? process_one_work+0x183/0x670
[ 1845.185026]  [<ffffffff810642b3>] worker_thread+0x113/0x370
[ 1845.185026]  [<ffffffff810641a0>] ? rescuer_thread+0x290/0x290
[ 1845.185026]  [<ffffffff8106bfba>] kthread+0xda/0xe0
[ 1845.185026]  [<ffffffff814ff0f0>] ? _raw_spin_unlock_irq+0x30/0x60
[ 1845.185026]  [<ffffffff8106bee0>] ? kthread_create_on_node+0x130/0x130
[ 1845.185026]  [<ffffffff8150751a>] ret_from_fork+0x7a/0xb0
[ 1845.185026]  [<ffffffff8106bee0>] ? kthread_create_on_node+0x130/0x130
[ 1845.185026] Code: 81 48 c7 c7 28 95 ad 81 31 c0 e8 9b da 01 00 e9 4f ff ff ff 66 0f 1f 44 00 00 55 48 89 e5 53 48 89 fb 48 83 ec 08 48 85 ff 74 1d <f6> 87 00 01 00 00 01 74 1e 48 8d 7b 38 83 6b 38 01 0f 94 c0 84
[ 1845.185026] RIP  [<ffffffff812cda81>] kobject_put+0x11/0x60
[ 1845.185026]  RSP <ffff88007ca5dd08>
[ 1845.185026] CR2: ffffffffa01601d0
[ 1845.185026] ---[ end trace 49a70afd109f5653 ]---

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-09-03 16:35:47 +09:30
Chen Gang
cc56ded3fd kernel/module.c: use scnprintf() instead of sprintf()
For some strings, they are permitted to be larger than PAGE_SIZE, so
need use scnprintf() instead of sprintf(), or it will cause issue.

One case is:

  if a module version is crazy defined (length more than PAGE_SIZE),
  'modinfo' command is still OK (print full contents),
  but for "cat /sys/modules/'modname'/version", will cause issue in kernel.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-08-20 15:37:46 +09:30
Steven Rostedt
0ce814096f module: Add NOARG flag for ops with param_set_bool_enable_only() set function
The ops that uses param_set_bool_enable_only() as its set function can
easily handle being used without an argument. There's no reason to
fail the loading of the module if it does not have one.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-08-20 15:37:43 +09:30
Linus Torvalds
8133633368 Nothing interesting. Except the most embarrassing bugfix ever. But let's
ignore that.
 
 Cheers,
 Rusty.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "Nothing interesting.  Except the most embarrassing bugfix ever.  But
  let's ignore that"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  module: cleanup call chain.
  module: do percpu allocation after uniqueness check.  No, really!
  modules: don't fail to load on unknown parameters.
  ABI: Clarify when /sys/module/MODULENAME is created
  There is no /sys/parameters
  module: don't modify argument of module_kallsyms_lookup_name()
2013-07-10 14:51:41 -07:00
Rusty Russell
9eb76d7797 module: cleanup call chain.
Fold alloc_module_percpu into percpu_modalloc().

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-07-03 10:15:10 +09:30
Rusty Russell
8d8022e8ab module: do percpu allocation after uniqueness check. No, really!
v3.8-rc1-5-g1fb9341 was supposed to stop parallel kvm loads exhausting
percpu memory on large machines:

    Now we have a new state MODULE_STATE_UNFORMED, we can insert the
    module into the list (and thus guarantee its uniqueness) before we
    allocate the per-cpu region.

In my defence, it didn't actually say the patch did this.  Just that
we "can".

This patch actually *does* it.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Jim Hull <jim.hull@hp.com>
Cc: stable@kernel.org # 3.8
2013-07-03 10:15:09 +09:30
Rusty Russell
54041d8a73 modules: don't fail to load on unknown parameters.
Although parameters are supposed to be part of the kernel API, experimental
parameters are often removed.  In addition, downgrading a kernel might cause
previously-working modules to fail to load.

On balance, it's probably better to warn, and load the module anyway.
This may let through a typo, but at least the logs will show it.

Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-07-02 15:38:21 +09:30