linux/kernel/module.c, branch v3.8

module: fix missing module_mutex unlock

2013-01-21T04:22:58Z

Commit 1fb9341ac348 ("module: put modules in list much earlier") moved some of the module initialization code around, and in the process changed the exit paths too. But for the duplicate export symbol error case the change made the ddebug_cleanup path jump to after the module mutex unlock, even though it happens with the mutex held. Rusty has some patches to split this function up into some helper functions, hopefully the mess of complex goto targets will go away eventually. Reported-by: Dan Carpenter Cc: Rusty Russell Signed-off-by: Linus Torvalds

Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2013-01-21T00:44:28Z

Pull module fixes and a virtio block fix from Rusty Russell: "Various minor fixes, but a slightly more complex one to fix the per-cpu overload problem introduced recently by kvm id changes." * tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: module: put modules in list much earlier. module: add new state MODULE_STATE_UNFORMED. module: prevent warning when finit_module a 0 sized file virtio-blk: Don't free ida when disk is in use

module, async: async_synchronize_full() on module init iff async is used

2013-01-16T17:05:33Z

If the default iosched is built as module, the kernel may deadlock while trying to load the iosched module on device probe if the probing was running off async. This is because async_synchronize_full() at the end of module init ends up waiting for the async job which initiated the module loading. async A modprobe 1. finds a device 2. registers the block device 3. request_module(default iosched) 4. modprobe in userland 5. load and init module 6. async_synchronize_full() Async A waits for modprobe to finish in request_module() and modprobe waits for async A to finish in async_synchronize_full(). Because there's no easy to track dependency once control goes out to userland, implementing properly nested flushing is difficult. For now, make module init perform async_synchronize_full() iff module init has queued async jobs as suggested by Linus. This avoids the described deadlock because iosched module doesn't use async and thus wouldn't invoke async_synchronize_full(). This is hacky and incomplete. It will deadlock if async module loading nests; however, this works around the known problem case and seems to be the best of bad options. For more details, please refer to the following thread. http://thread.gmane.org/gmane.linux.kernel/1420814 Signed-off-by: Tejun Heo Reported-by: Alex Riesen Tested-by: Ming Lei Tested-by: Alex Riesen Cc: Arjan van de Ven Cc: Jens Axboe Signed-off-by: Linus Torvalds

module: put modules in list much earlier.

2013-01-12T02:57:46Z

Prarit's excellent bug report: > In recent Fedora releases (F17 & F18) some users have reported seeing > messages similar to > > [ 15.478160] kvm: Could not allocate 304 bytes percpu data > [ 15.478174] PERCPU: allocation failed, size=304 align=32, alloc from > reserved chunk failed > > during system boot. In some cases, users have also reported seeing this > message along with a failed load of other modules. > > What is happening is systemd is loading an instance of the kvm module for > each cpu found (see commit e9bda3b). When the module load occurs the kernel > currently allocates the modules percpu data area prior to checking to see > if the module is already loaded or is in the process of being loaded. If > the module is already loaded, or finishes load, the module loading code > releases the current instance's module's percpu data. 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. Reported-by: Prarit Bhargava Signed-off-by: Rusty Russell Tested-by: Prarit Bhargava

module: add new state MODULE_STATE_UNFORMED.

2013-01-12T02:57:05Z

You should never look at such a module, so it's excised from all paths which traverse the modules list. We add the state at the end, to avoid gratuitous ABI break (ksplice). Signed-off-by: Rusty Russell

module: prevent warning when finit_module a 0 sized file

2013-01-03T00:40:32Z

If we try to finit_module on a file sized 0 bytes vmalloc will scream and spit out a warning. Since modules have to be bigger than 0 bytes anyways we can just check that beforehand and avoid the warning. Signed-off-by: Sasha Levin Signed-off-by: Rusty Russell

Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2012-12-19T15:55:08Z

Pull module update from Rusty Russell: "Nothing all that exciting; a new module-from-fd syscall for those who want to verify the source of the module (ChromeOS) and/or use standard IMA on it or other security hooks." * tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: MODSIGN: Fix kbuild output when using default extra_certificates MODSIGN: Avoid using .incbin in C source modules: don't hand 0 to vmalloc. module: Remove a extra null character at the top of module->strtab. ASN.1: Use the ASN1_LONG_TAG and ASN1_INDEFINITE_LENGTH constants ASN.1: Define indefinite length marker constant moduleparam: use __UNIQUE_ID() __UNIQUE_ID() MODSIGN: Add modules_sign make target powerpc: add finit_module syscall. ima: support new kernel module syscall add finit_module syscall to asm-generic ARM: add finit_module syscall to ARM security: introduce kernel_module_from_file hook module: add flags arg to sys_finit_module() module: add syscall to load module from fd

kernel: remove reference to feature-removal-schedule.txt

2012-12-18T01:15:12Z

In commit 9c0ece069b32 ("Get rid of Documentation/feature-removal.txt"), Linus removed feature-removal-schedule.txt from Documentation, but there is still some reference to this file. So remove them. Signed-off-by: Tao Ma Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

modules: don't hand 0 to vmalloc.

2012-12-14T02:36:43Z

In commit d0a21265dfb5fa8a David Rientjes unified various archs' module_alloc implementation (including x86) and removed the graduitous shortcut for size == 0. Then, in commit de7d2b567d040e3b, Joe Perches added a warning for zero-length vmallocs, which can happen without kallsyms on modules with no init sections (eg. zlib_deflate). Fix this once and for all; the module code has to handle zero length anyway, so get it right at the caller and remove the now-gratuitous checks within the arch-specific module_alloc implementations. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=42608 Reported-by: Conrad Kostecki Cc: David Rientjes Cc: Joe Perches Signed-off-by: Rusty Russell

module: Remove a extra null character at the top of module->strtab.

2012-12-14T02:36:43Z

There is a extra null character('\0') at the top of module->strtab for each module. Commit 59ef28b introduced this bug and this patch fixes it. Live dump log of the current linus git kernel(HEAD is 2844a4870): ============================================================================ crash> mod | grep loop ffffffffa01db0a0 loop 16689 (not loaded) [CONFIG_KALLSYMS] crash> module.core_symtab ffffffffa01db0a0 core_symtab = 0xffffffffa01db320crash> rd 0xffffffffa01db320 12 ffffffffa01db320: 0000005500000001 0000000000000000 ....U........... ffffffffa01db330: 0000000000000000 0002007400000002 ............t... ffffffffa01db340: ffffffffa01d8000 0000000000000038 ........8....... ffffffffa01db350: 001a00640000000e ffffffffa01daeb0 ....d........... ffffffffa01db360: 00000000000000a0 0002007400000019 ............t... ffffffffa01db370: ffffffffa01d8068 000000000000001b h............... crash> module.core_strtab ffffffffa01db0a0 core_strtab = 0xffffffffa01dbb30 "" crash> rd 0xffffffffa01dbb30 4 ffffffffa01dbb30: 615f70616d6b0000 66780063696d6f74 ..kmap_atomic.xf ffffffffa01dbb40: 73636e75665f7265 72665f646e696600 er_funcs.find_fr ============================================================================ We expect Just first one byte of '\0', but actually first two bytes are '\0'. Here is The relationship between symtab and strtab. symtab_idx strtab_idx symbol ----------------------------------------------- 0 0x1 "\0" # startab_idx should be 0 1 0x2 "kmap_atomic" 2 0xe "xfer_funcs" 3 0x19 "find_fr..." By applying this patch, it becomes as follows. symtab_idx strtab_idx symbol ----------------------------------------------- 0 0x0 "\0" # extra byte is removed 1 0x1 "kmap_atomic" 2 0xd "xfer_funcs" 3 0x18 "find_fr..." Signed-off-by: Satoru Takeuchi Cc: Masaki Kimura Cc: Rusty Russell Cc: Greg Kroah-Hartman Signed-off-by: Rusty Russell