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* module: Remove module size limitSasha Levin2012-04-02
| | | | | | | | | | | | | | | | commit f946eeb9313ff1470758e171a60fe7438a2ded3f upstream. Module size was limited to 64MB, this was legacy limitation due to vmalloc() which was removed a while ago. Limiting module size to 64MB is both pointless and affects real world use cases. Cc: Tim Abbott <tim.abbott@oracle.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* Merge branch 'staging-next' of ↵Linus Torvalds2011-05-23
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6 * 'staging-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6: (970 commits) staging: usbip: replace usbip_u{dbg,err,info} and printk with dev_ and pr_ staging:iio: Trivial kconfig reorganization and uniformity improvements. staging:iio:documenation partial update. staging:iio: use pollfunc allocation helpers in remaining drivers. staging:iio:max1363 misc cleanups and use of for_each_bit_set to simplify event code spitting out. staging:iio: implement an iio_info structure to take some of the constant elements out of iio_dev. staging:iio:meter:ade7758: Use private data space from iio_allocate_device staging:iio:accel:lis3l02dq make write_reg_8 take value not a pointer to value. staging:iio: ring core cleanups + check if read_last available in lis3l02dq staging:iio:core cleanup: squash tiny wrappers and use dev_set_name to handle creation of event interface name. staging:iio: poll func allocation clean up. staging:iio:ad7780 trivial unused header cleanup. staging:iio:adc: AD7780: Use private data space from iio_allocate_device + trivial fixes staging:iio:adc:AD7780: Convert to new channel registration method staging:iio:adc: AD7606: Drop dev_data in favour of iio_priv() staging:iio:adc: AD7606: Consitently use indio_dev staging:iio: Rip out helper for software rings. staging:iio:adc:AD7298: Use private data space from iio_allocate_device staging:iio: rationalization of different buffer implementation hooks. staging:iio:imu:adis16400 avoid allocating rx, tx, and state separately from iio_dev. ... Fix up trivial conflicts in - drivers/staging/intel_sst/intelmid.c: patches applied in both branches - drivers/staging/rt2860/common/cmm_data_{pci,usb}.c: removed vs spelling - drivers/staging/usbip/vhci_sysfs.c: trivial header file inclusion
| * modules: Enabled dynamic debugging for staging modulesRoland Vossen2011-04-25
| | | | | | | | | | | | | | | | | | | | | | | | | | Driver modules from the staging directory are marked 'tainted' by module.c. Subsequently, tainted modules are denied dynamic debugging. This is unwanted behavior, since staging modules should be able to use the dynamic debugging mechanism. Please merge this also into the staging-linus branch. Signed-off-by: Roland Vossen <rvossen@broadcom.com> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | module: Use binary search in lookup_symbol()Alessio Igor Bogani2011-05-19
| | | | | | | | | | | | | | | | | | | | | | | | | | The function is_exported() with its helper function lookup_symbol() are used to verify if a provided symbol is effectively exported by the kernel or by the modules. Now that both have their symbols sorted we can replace a linear search with a binary search which provide a considerably speed-up. This work was supported by a hardware donation from the CE Linux Forum. Signed-off-by: Alessio Igor Bogani <abogani@kernel.org> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* | module: Use the binary search for symbols resolutionAlessio Igor Bogani2011-05-19
| | | | | | | | | | | | | | | | | | | | Takes advantage of the order and locates symbols using binary search. This work was supported by a hardware donation from the CE Linux Forum. Signed-off-by: Alessio Igor Bogani <abogani@kernel.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Tested-by: Dirk Behme <dirk.behme@googlemail.com>
* | module: each_symbol_section instead of each_symbolRusty Russell2011-05-19
| | | | | | | | | | | | | | | | | | | | Instead of having a callback function for each symbol in the kernel, have a callback for each array of symbols. This eases the logic when we move to sorted symbols and binary search. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Alessio Igor Bogani <abogani@kernel.org>
* | module: split unset_section_ro_nx function.Jan Glauber2011-05-19
| | | | | | | | | | | | | | | | Split the unprotect function into a function per section to make the code more readable and add the missing static declaration. Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* | module: undo module RONX protection correctly.Jan Glauber2011-05-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While debugging I stumbled over two problems in the code that protects module pages. First issue is that disabling the protection before freeing init or unload of a module is not symmetric with the enablement. For instance, if pages are set to RO the page range from module_core to module_core + core_ro_size is protected. If a module is unloaded the page range from module_core to module_core + core_size is set back to RW. So pages that were not set to RO are also changed to RW. This is not critical but IMHO it should be symmetric. Second issue is that while set_memory_rw & set_memory_ro are used for RO/RW changes only set_memory_nx is involved for NX/X. One would await that the inverse function is called when the NX protection should be removed, which is not the case here, unless I'm missing something. Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* | module: zero mod->init_ro_size after init is freed.Jan Glauber2011-05-19
| | | | | | | | | | | | | | | | | | Reset mod->init_ro_size to zero after the init part of a module is unloaded. Otherwise we need to check if module->init is NULL in the unprotect functions in the next patch. Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* | minor ANSI prototype sparse fixDaniel J Blueman2011-05-19
|/ | | | | | | | Fix function prototype to be ANSI-C compliant, consistent with other function prototypes, addressing a sparse warning. Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Fix common misspellingsLucas De Marchi2011-03-31
| | | | | | Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
* printk: use %pK for /proc/kallsyms and /proc/modulesKees Cook2011-03-22
| | | | | | | | | | | | | | | | | | | | | | | In an effort to reduce kernel address leaks that might be used to help target kernel privilege escalation exploits, this patch uses %pK when displaying addresses in /proc/kallsyms, /proc/modules, and /sys/module/*/sections/*. Note that this changes %x to %p, so some legitimately 0 values in /proc/kallsyms would have changed from 00000000 to "(null)". To avoid this, "(null)" is not used when using the "K" format. Anything that was already successfully parsing "(null)" in addition to full hex digits should have no problem with this change. (Thanks to Joe Perches for the suggestion.) Due to the %x to %p, "void *" casts are needed since these addresses are already "unsigned long" everywhere internally, due to their starting life as ELF section offsets. Signed-off-by: Kees Cook <kees.cook@canonical.com> Cc: Eugene Teo <eugene@redhat.com> Cc: Dan Rosenberg <drosenberg@vsecurity.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tracepoints: Fix section alignment using pointer arrayMathieu Desnoyers2011-02-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make the tracepoints more robust, making them solid enough to handle compiler changes by not relying on anything based on compiler-specific behavior with respect to structure alignment. Implement an approach proposed by David Miller: use an array of const pointers to refer to the individual structures, and export this pointer array through the linker script rather than the structures per se. It will consume 32 extra bytes per tracepoint (24 for structure padding and 8 for the pointers), but are less likely to break due to compiler changes. History: commit 7e066fb8 tracepoints: add DECLARE_TRACE() and DEFINE_TRACE() added the aligned(32) type and variable attribute to the tracepoint structures to deal with gcc happily aligning statically defined structures on 32-byte multiples. One attempt was to use a 8-byte alignment for tracepoint structures by applying both the variable and type attribute to tracepoint structures definitions and declarations. It worked fine with gcc 4.5.1, but broke with gcc 4.4.4 and 4.4.5. The reason is that the "aligned" attribute only specify the _minimum_ alignment for a structure, leaving both the compiler and the linker free to align on larger multiples. Because tracepoint.c expects the structures to be placed as an array within each section, up-alignment cause NULL-pointer exceptions due to the extra unexpected padding. (this patch applies on top of -tip) Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: David S. Miller <davem@davemloft.net> LKML-Reference: <20110126222622.GA10794@Krystal> CC: Frederic Weisbecker <fweisbec@gmail.com> CC: Ingo Molnar <mingo@elte.hu> CC: Thomas Gleixner <tglx@linutronix.de> CC: Andrew Morton <akpm@linux-foundation.org> CC: Peter Zijlstra <peterz@infradead.org> CC: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* module: Move RO/NX module protection to after ftrace module updateSteven Rostedt2010-12-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The commit: 84e1c6bb38eb318e456558b610396d9f1afaabf0 x86: Add RO/NX protection for loadable kernel modules Broke the function tracer with this output: ------------[ cut here ]------------ WARNING: at kernel/trace/ftrace.c:1014 ftrace_bug+0x114/0x171() Hardware name: Precision WorkStation 470 Modules linked in: i2c_core(+) Pid: 86, comm: modprobe Not tainted 2.6.37-rc2+ #68 Call Trace: [<ffffffff8104e957>] warn_slowpath_common+0x85/0x9d [<ffffffffa00026db>] ? __process_new_adapter+0x7/0x34 [i2c_core] [<ffffffffa00026db>] ? __process_new_adapter+0x7/0x34 [i2c_core] [<ffffffff8104e989>] warn_slowpath_null+0x1a/0x1c [<ffffffff810a9dfe>] ftrace_bug+0x114/0x171 [<ffffffffa00026db>] ? __process_new_adapter+0x7/0x34 [i2c_core] [<ffffffff810aa0db>] ftrace_process_locs+0x1ae/0x274 [<ffffffffa00026db>] ? __process_new_adapter+0x7/0x34 [i2c_core] [<ffffffff810aa29e>] ftrace_module_notify+0x39/0x44 [<ffffffff814405cf>] notifier_call_chain+0x37/0x63 [<ffffffff8106e054>] __blocking_notifier_call_chain+0x46/0x5b [<ffffffff8106e07d>] blocking_notifier_call_chain+0x14/0x16 [<ffffffff8107ffde>] sys_init_module+0x73/0x1f3 [<ffffffff8100acf2>] system_call_fastpath+0x16/0x1b ---[ end trace 2aff4f4ca53ec746 ]--- ftrace faulted on writing [<ffffffffa00026db>] __process_new_adapter+0x7/0x34 [i2c_core] The cause was that the module text was set to read only before ftrace could convert the calls to mcount to nops. Thus, the conversions failed due to not being able to write to the text locations. The simple fix is to move setting the module to read only after the module notifiers are called (where ftrace sets the module mcounts to nops). Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* Merge commit 'v2.6.37-rc7' into x86/securityIngo Molnar2010-12-23
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| * tracing: Fix module use of trace_bprintk()Steven Rostedt2010-11-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On use of trace_printk() there's a macro that determines if the format is static or a variable. If it is static, it defaults to __trace_bprintk() otherwise it uses __trace_printk(). A while ago, Lai Jiangshan added __trace_bprintk(). In that patch, we discussed a way to allow modules to use it. The difference between __trace_bprintk() and __trace_printk() is that for faster processing, just the format and args are stored in the trace instead of running it through a sprintf function. In order to do this, the format used by the __trace_bprintk() had to be persistent. See commit 1ba28e02a18cbdbea123836f6c98efb09cbf59ec The problem comes with trace_bprintk() where the module is unloaded. The pointer left in the buffer is still pointing to the format. To solve this issue, the formats in the module were copied into kernel core. If the same format was used, they would use the same copy (to prevent memory leak). This all worked well until we tried to merge everything. At the time this was written, Lai Jiangshan, Frederic Weisbecker, Ingo Molnar and myself were all touching the same code. When this was merged, we lost the part of it that was in module.c. This kept out the copying of the formats and unloading the module could cause bad pointers left in the ring buffer. This patch adds back (with updates required for current kernel) the module code that sets up the necessary pointers. Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | x86: Add RO/NX protection for loadable kernel modulesmatthieu castet2010-11-18
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is a logical extension of the protection provided by CONFIG_DEBUG_RODATA to LKMs. The protection is provided by splitting module_core and module_init into three logical parts each and setting appropriate page access permissions for each individual section: 1. Code: RO+X 2. RO data: RO+NX 3. RW data: RW+NX In order to achieve proper protection, layout_sections() have been modified to align each of the three parts mentioned above onto page boundary. Next, the corresponding page access permissions are set right before successful exit from load_module(). Further, free_module() and sys_init_module have been modified to set module_core and module_init as RW+NX right before calling module_free(). By default, the original section layout and access flags are preserved. When compiled with CONFIG_DEBUG_SET_MODULE_RONX=y, the patch will page-align each group of sections to ensure that each page contains only one type of content and will enforce RO/NX for each group of pages. -v1: Initial proof-of-concept patch. -v2: The patch have been re-written to reduce the number of #ifdefs and to make it architecture-agnostic. Code formatting has also been corrected. -v3: Opportunistic RO/NX protection is now unconditional. Section page-alignment is enabled when CONFIG_DEBUG_RODATA=y. -v4: Removed most macros and improved coding style. -v5: Changed page-alignment and RO/NX section size calculation -v6: Fixed comments. Restricted RO/NX enforcement to x86 only -v7: Introduced CONFIG_DEBUG_SET_MODULE_RONX, added calls to set_all_modules_text_rw() and set_all_modules_text_ro() in ftrace -v8: updated for compatibility with linux 2.6.33-rc5 -v9: coding style fixes -v10: more coding style fixes -v11: minor adjustments for -tip -v12: minor adjustments for v2.6.35-rc2-tip -v13: minor adjustments for v2.6.37-rc1-tip Signed-off-by: Siarhei Liakh <sliakh.lkml@gmail.com> Signed-off-by: Xuxian Jiang <jiang@cs.ncsu.edu> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Andi Kleen <ak@muc.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Dave Jones <davej@redhat.com> Cc: Kees Cook <kees.cook@canonical.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <4CE2F914.9070106@free.fr> [ minor cleanliness edits, -v14: build failure fix ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* (trivial) Fix compiler warning in kernel/modules.cMichał Mirosław2010-10-27
| | | | | | | | | | | Building with CONFIG_KALLSYMS=n gives following warning: /mnt/src/linux-git/kernel/module.c: In function ‘post_relocation’: /mnt/src/linux-git/kernel/module.c:2534:2: warning: passing argument 2 of ‘add_kallsyms’ discards qualifiers from pointer target type /mnt/src/linux-git/kernel/module.c:2038:13: note: expected ‘struct load_info *’ but argument is of type ‘const struct load_info *’ Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* Merge commit 'v2.6.36-rc7' into perf/coreIngo Molnar2010-10-08
|\ | | | | | | | | | | | | | | | | Conflicts: arch/x86/kernel/module.c Merge reason: Resolve the conflict, pick up fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * modules: Fix module_bug_list list corruption raceLinus Torvalds2010-10-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With all the recent module loading cleanups, we've minimized the code that sits under module_mutex, fixing various deadlocks and making it possible to do most of the module loading in parallel. However, that whole conversion totally missed the rather obscure code that adds a new module to the list for BUG() handling. That code was doubly obscure because (a) the code itself lives in lib/bugs.c (for dubious reasons) and (b) it gets called from the architecture-specific "module_finalize()" rather than from generic code. Calling it from arch-specific code makes no sense what-so-ever to begin with, and is now actively wrong since that code isn't protected by the module loading lock any more. So this commit moves the "module_bug_{finalize,cleanup}()" calls away from the arch-specific code, and into the generic code - and in the process protects it with the module_mutex so that the list operations are now safe. Future fixups: - move the module list handling code into kernel/module.c where it belongs. - get rid of 'module_bug_list' and just use the regular list of modules (called 'modules' - imagine that) that we already create and maintain for other reasons. Reported-and-tested-by: Thomas Gleixner <tglx@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Adrian Bunk <bunk@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | jump label: Base patch for jump labelJason Baron2010-09-22
|/ | | | | | | | | | | | | | | | | base patch to implement 'jump labeling'. Based on a new 'asm goto' inline assembly gcc mechanism, we can now branch to labels from an 'asm goto' statment. This allows us to create a 'no-op' fastpath, which can subsequently be patched with a jump to the slowpath code. This is useful for code which might be rarely used, but which we'd like to be able to call, if needed. Tracepoints are the current usecase that these are being implemented for. Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jason Baron <jbaron@redhat.com> LKML-Reference: <ee8b3595967989fdaf84e698dc7447d315ce972a.1284733808.git.jbaron@redhat.com> [ cleaned up some formating ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* module: cleanup comments, remove noinlineRusty Russell2010-08-04
| | | | | | | | | | On my (32-bit x86) machine, sys_init_module() uses 124 bytes of stack once load_module() is inlined. This effectively reverts ffb4ba76 which inlined it due to stack pressure. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: group post-relocation functions into post_relocation()Rusty Russell2010-08-04
| | | | | | | | | | | | This simply hoists more code out of load_module; we also put the identification of the extable and dynamic debug table in with the others in find_module_sections(). We move the taint check to the actual add/remove of the dynamic debug info: this is certain (find_module_sections is too early). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Yehuda Sadeh <yehuda@hq.newdream.net>
* module: move module args strndup_user to just before useRusty Russell2010-08-04
| | | | | | | Instead of copying and allocating the args and storing it in load_info, we can just allocate them right before we need them. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: pass load_info into other functionsRusty Russell2010-08-04
| | | | | | | Pass the struct load_info into all the other functions in module loading. This neatens things and makes them more consistent. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: fix sysfs cleanup for !CONFIG_SYSFSRusty Russell2010-08-04
| | | | | | | | | | | Restore the stub module_remove_modinfo_attrs, remove the now-unused !CONFIG_SYSFS module_sysfs_init. Also, rename mod_kobject_remove() to mod_sysfs_teardown() as it is the logical counterpart to mod_sysfs_setup now. Reported-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: sysfs cleanupRusty Russell2010-08-04
| | | | | | | | | We change the sysfs functions to take struct load_info, and call them all in mod_sysfs_setup(). We also clean up the #ifdefs a little. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: layout_and_allocateRusty Russell2010-08-04
| | | | | | | | | | | | | | | | layout_and_allocate() does everything up to and including the final struct module placement inside the allocated module memory. We have to store the symbol layout information in our struct load_info though. This avoids the nasty code we had before where 'mod' pointed first to the version inside the temporary allocation containing the entire file, then later was moved to point to the real struct module: now the main code only ever sees the final module address. (Includes fix for the Tony Luck-found Linus-diagnosed failure path error). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: fix crash in get_ksymbol() when oopsing in module initRusty Russell2010-08-04
| | | | | | | | | | | | | | | | | | Andrew had the sole pleasure of tickling this bug in linux-next; when we set up "info->strtab" it's pointing into the temporary copy of the module. For most uses that is fine, but kallsyms keeps a pointer around during module load (inside mod->strtab). If we oops for some reason inside a module's init function, kallsyms will use the mod->strtab pointer into the now-freed temporary module copy. (Later oopses work fine: after init we overwrite mod->strtab to point to a compacted core-only strtab). Reported-by: Andrew "Grumpy" Morton <akpm@linux-foundation.org> Signed-off-by: Rusty "Buggy" Russell <rusty@rustcorp.com.au> Tested-by: Andrew "Happy" Morton <akpm@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: kallsyms functions take struct load_infoRusty Russell2010-08-04
| | | | | | Simple refactor causes us to lift struct definition to top of file. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor out section header rewriting: FIX modversionsRusty Russell2010-08-04
| | | | | | | We can't do the find_sec after removing the SHF_ALLOC flags; it won't find the sections. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor out section header rewritingRusty Russell2010-08-04
| | | | | | | | | Put all the "rewrite and check section headers" in one place. This adds another iteration over the sections, but it's far clearer. We iterate once for every find_section() so we already iterate over many times. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: add load_infoLinus Torvalds2010-08-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Btw, here's a patch that _looks_ large, but it really pretty trivial, and sets things up so that it would be way easier to split off pieces of the module loading. The reason it looks large is that it creates a "module_info" structure that contains all the module state that we're building up while loading, instead of having individual variables for all the indices etc. So the patch ends up being large, because every "symindex" access instead becomes "info.index.sym" etc. That may be a few characters longer, but it then means that we can just pass a pointer to that "info" structure around. and let all the pieces fill it in very naturally. As an example of that, the patch also moves the initialization of all those convenience variables into a "setup_module_info()" function. And at this point it really does become very natural to start to peel off some of the error labels and move them into the helper functions - now the "truncated" case is gone, and is handled inside that setup function instead. So maybe you don't like this approach, and it does make the variable accesses a bit longer, but I don't think unreadably so. And the patch really does look big and scary, but there really should be absolutely no semantic changes - most of it was a trivial and mindless rename. In fact, it was so mindless that I on purpose kept the existing helper functions looking like this: - err = check_modinfo(mod, sechdrs, infoindex, versindex); + err = check_modinfo(mod, info.sechdrs, info.index.info, info.index.vers); rather than changing them to just take the "info" pointer. IOW, a second phase (if you think the approach is ok) would change that calling convention to just do err = check_modinfo(mod, &info); (and same for "layout_sections()", "layout_symtabs()" etc.) Similarly, while right now it makes things _look_ bigger, with things like this: versindex = find_sec(hdr, sechdrs, secstrings, "__versions"); becoming info->index.vers = find_sec(info->hdr, info->sechdrs, info->secstrings, "__versions"); in the new "setup_module_info()" function, that's again just a result of it being a search-and-replace patch. By using the 'info' pointer, we could just change the 'find_sec()' interface so that it ends up being info->index.vers = find_sec(info, "__versions"); instead, and then we'd actually have a shorter and more readable line. So for a lot of those mindless variable name expansions there's would be room for separate cleanups. I didn't move quite everything in there - if we do this to layout_symtabs, for example, we'd want to move the percpu, symoffs, stroffs, *strmap variables to be fields in that module_info structure too. But that's a much smaller patch, I moved just the really core stuff that is currently being set up and used in various parts. But even in this rough form, it removes close to 70 lines from that function (but adds 22 lines overall, of course - the structure definition, the helper function declarations and call-sites etc etc). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: reduce stack usage for each_symbol()Linus Torvalds2010-08-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | And now that I'm looking at that call-chain (to see if it would make sense to use some other more specific lock - doesn't look like it: all the readers are using RCU and this is the only writer), I also give you this trivial one-liner. It changes each_symbol() to not put that constant array on the stack, resulting in changing movq $C.388.31095, %rsi #, tmp85 subq $376, %rsp #, movq %rdi, %rbx # fn, fn leaq -208(%rbp), %rdi #, tmp84 movq %rbx, %rdx # fn, rep movsl xorl %esi, %esi # leaq -208(%rbp), %rdi #, tmp87 movq %r12, %rcx # data, call each_symbol_in_section.clone.0 # into xorl %esi, %esi # subq $216, %rsp #, movq %rdi, %rbx # fn, fn movq $arr.31078, %rdi #, call each_symbol_in_section.clone.0 # which is not so much about being obviously shorter and simpler because we don't unnecessarily copy that constant array around onto the stack, but also about having a much smaller stack footprint (376 vs 216 bytes - see the update of 'rsp'). Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor load_module part 5Rusty Russell2010-08-04
| | | | | | | | | | 1) Extract out the relocation loop into apply_relocations 2) Extract license and version checks into check_module_license_and_versions 3) Extract icache flushing into flush_module_icache 4) Move __obsparm warning into find_module_sections 5) Move license setting into check_modinfo. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor load_module part 4Rusty Russell2010-08-04
| | | | | | | | | | | Allocate references inside module_unload_init(), clean up inside module_unload_free(). This version fixed to do allocation before __this_cpu_write, thanks to bug reports from linux-next from Dave Young <hidave.darkstar@gmail.com> and Stephen Rothwell <sfr@canb.auug.org.au>. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor load_module part 3Rusty Russell2010-08-04
| | | | | | | Extract out the allocation and copying in from userspace, and the first set of modinfo checks. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor load_module part 2Linus Torvalds2010-08-04
| | | | | | | | | | Here's a second one. It's slightly less trivial - since we now have error cases - and equally untested so it may well be totally broken. But it also cleans up a bit more, and avoids one of the goto targets, because the "move_module()" helper now does both allocations or none. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: refactor load_moduleLinus Torvalds2010-08-04
| | | | | | | | | | I'd start from the trivial stuff. There's a fair amount of straight-line code that just makes the function hard to read just because you have to page up and down so far. Some of it is trivial to just create a helper function for. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: module_unload_init() cleanupEric Dumazet2010-08-04
| | | | | | | | No need to clear mod->refptr in module_unload_init(), since alloc_percpu() already clears allocated chunks. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed unused var)
* dynamic debug: move ddebug_remove_module() down into free_module()Jason Baron2010-07-27
| | | | | | | | | | | | | | | | | | | The command echo "file ec.c +p" >/sys/kernel/debug/dynamic_debug/control causes an oops. Move the call to ddebug_remove_module() down into free_module(). In this way it should be called from all error paths. Currently, we are missing the remove if the module init routine fails. Signed-off-by: Jason Baron <jbaron@redhat.com> Reported-by: Thomas Renninger <trenn@suse.de> Tested-by: Thomas Renninger <trenn@suse.de> Cc: <stable@kernel.org> [2.6.32+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* module: initialize module dynamic debug laterYehuda Sadeh2010-07-04
| | | | | | | | | | | | | We should initialize the module dynamic debug datastructures only after determining that the module is not loaded yet. This fixes a bug that introduced in 2.6.35-rc2, where when a trying to load a module twice, we also load it's dynamic printing data twice which causes all sorts of nasty issues. Also handle the dynamic debug cleanup later on failure. Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed a #ifdef) Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* module: fix bne2 "gave up waiting for init of module libcrc32c"Rusty Russell2010-06-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Problem: it's hard to avoid an init routine stumbling over a request_module these days. And it's not clear it's always a bad idea: for example, a module like kvm with dynamic dependencies on kvm-intel or kvm-amd would be neater if it could simply request_module the right one. In this particular case, it's libcrc32c: libcrc32c_mod_init crypto_alloc_shash crypto_alloc_tfm crypto_find_alg crypto_alg_mod_lookup crypto_larval_lookup request_module If another module is waiting inside resolve_symbol() for libcrc32c to finish initializing (ie. bne2 depends on libcrc32c) then it does so holding the module lock, and our request_module() can't make progress until that is released. Waiting inside resolve_symbol() without the lock isn't all that hard: we just need to pass the -EBUSY up the call chain so we can sleep where we don't hold the lock. Error reporting is a bit trickier: we need to copy the name of the unfinished module before releasing the lock. Other notes: 1) This also fixes a theoretical issue where a weak dependency would allow symbol version mismatches to be ignored. 2) We rename use_module to ref_module to make life easier for the only external user (the out-of-tree ksplice patches). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tim Abbot <tabbott@ksplice.com> Tested-by: Brandon Philips <bphilips@suse.de>
* module: verify_export_symbols under the lockRusty Russell2010-06-04
| | | | | | | | | | | | | It disabled preempt so it was "safe", but nothing stops another module slipping in before this module is added to the global list now we don't hold the lock the whole time. So we check this just after we check for duplicate modules, and just before we put the module in the global list. (find_symbol finds symbols in coming and going modules, too). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: move find_module check to endLinus Torvalds2010-06-04
| | | | | | | | | | | | | | | | | | | I think Rusty may have made the lock a bit _too_ finegrained there, and didn't add it to some places that needed it. It looks, for example, like PATCH 1/2 actually drops the lock in places where it's needed ("find_module()" is documented to need it, but now load_module() didn't hold it at all when it did the find_module()). Rather than adding a new "module_loading" list, I think we should be able to just use the existing "modules" list, and just fix up the locking a bit. In fact, maybe we could just move the "look up existing module" a bit later - optimistically assuming that the module doesn't exist, and then just undoing the work if it turns out that we were wrong, just before adding ourselves to the list. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: make locking more fine-grained.Rusty Russell2010-06-04
| | | | | | | | | | | | | | | Kay Sievers <kay.sievers@vrfy.org> reports that we still have some contention over module loading which is slowing boot. Linus also disliked a previous "drop lock and regrab" patch to fix the bne2 "gave up waiting for init of module libcrc32c" message. This is more ambitious: we only grab the lock where we need it. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Brandon Philips <brandon@ifup.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Linus Torvalds <torvalds@linux-foundation.org>
* module: Make module sysfs functions private.Rusty Russell2010-06-04
| | | | | | | | | | | These were placed in the header in ef665c1a06 to get the various SYSFS/MODULE config combintations to compile. That may have been necessary then, but it's not now. These functions are all local to module.c. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Randy Dunlap <randy.dunlap@oracle.com>
* module: move sysfs exposure to end of load_moduleRusty Russell2010-06-04
| | | | | | | | | | | This means a little extra work, but is more logical: we don't put anything in sysfs until we're about to put the module into the global list an parse its parameters. This also gives us a logical place to put duplicate module detection in the next patch. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
* module: fix kdb's illicit use of struct module_use.Rusty Russell2010-06-04
| | | | | | | | | Linus changed the structure, and luckily this didn't compile any more. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Martin Hicks <mort@sgi.com>
* module: Make the 'usage' lists be two-wayLinus Torvalds2010-06-04
| | | | | | | | | | | | | | | | | | | | | | When adding a module that depends on another one, we used to create a one-way list of "modules_which_use_me", so that module unloading could see who needs a module. It's actually quite simple to make that list go both ways: so that we not only can see "who uses me", but also see a list of modules that are "used by me". In fact, we always wanted that list in "module_unload_free()": when we unload a module, we want to also release all the other modules that are used by that module. But because we didn't have that list, we used to first iterate over all modules, and then iterate over each "used by me" list of that module. By making the list two-way, we simplify module_unload_free(), and it allows for some trivial fixes later too. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (cleaned & rebased)
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