linux/kernel/module.c, branch v2.6.30

async: Fix module loading async-work regression

2009-04-11T19:44:49Z

Several drivers use asynchronous work to do device discovery, and we synchronize with them in the compiled-in case before we actually try to mount root filesystems etc. However, when compiled as modules, that synchronization is missing - the module loading completes, but the driver hasn't actually finished probing for devices, and that means that any user mode that expects to use the devices after the 'insmod' is now potentially broken. We already saw one case of a similar issue in the ACPI battery code, where the kernel itself expected the module to be all done, and unmapped the init memory - but the async device discovery was still running. That got hacked around by just removing the "__init" (see commit 5d38258ec026921a7b266f4047ebeaa75db358e5 "ACPI battery: fix async boot oops"), but the real fix is to just make the module loading wait for all async work to be completed. It will slow down module loading, but since common devices should be built in anyway, and since the bug is really annoying and hard to handle from user space (and caused several S3 resume regressions), the simple fix to wait is the right one. This fixes at least http://bugzilla.kernel.org/show_bug.cgi?id=13063 but probably a few other bugzilla entries too (12936, for example), and is confirmed to fix Rafael's storage driver breakage after resume bug report (no bugzilla entry). We should also be able to now revert that ACPI battery fix. Reported-and-tested-by: Rafael J. Wysocki Tested-by: Heinz Diehl Acked-by: Arjan van de Ven Signed-off-by: Linus Torvalds

Revert "module: remove the SHF_ALLOC flag on the __versions section."

2009-04-07T07:42:43Z

This reverts commit 9cb610d8e35fe3ec95a2fe2030b02f85aeea83c1. This was an impressively stupid patch. Firstly, we reset the SHF_ALLOC flag lower down in the same function, so the patch was useless. Even better, find_sec() ignores sections with SHF_ALLOC not set, so it breaks CONFIG_MODVERSIONS=y with CONFIG_MODULE_FORCE_LOAD=n, which refuses to load the module since it can't find the __versions section. Signed-off-by: Rusty Russell

Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2009-04-05T18:04:19Z

* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (413 commits) tracing, net: fix net tree and tracing tree merge interaction tracing, powerpc: fix powerpc tree and tracing tree interaction ring-buffer: do not remove reader page from list on ring buffer free function-graph: allow unregistering twice trace: make argument 'mem' of trace_seq_putmem() const tracing: add missing 'extern' keywords to trace_output.h tracing: provide trace_seq_reserve() blktrace: print out BLK_TN_MESSAGE properly blktrace: extract duplidate code blktrace: fix memory leak when freeing struct blk_io_trace blktrace: fix blk_probes_ref chaos blktrace: make classic output more classic blktrace: fix off-by-one bug blktrace: fix the original blktrace blktrace: fix a race when creating blk_tree_root in debugfs blktrace: fix timestamp in binary output tracing, Text Edit Lock: cleanup tracing: filter fix for TRACE_EVENT_FORMAT events ftrace: Using FTRACE_WARN_ON() to check "freed record" in ftrace_release() x86: kretprobe-booster interrupt emulation code fix ... Fix up trivial conflicts in arch/parisc/include/asm/ftrace.h include/linux/memory.h kernel/extable.c kernel/module.c

Merge branch 'tracing/core-v2' into tracing-for-linus

2009-04-01T22:49:02Z

Conflicts: include/linux/slub_def.h lib/Kconfig.debug mm/slob.c mm/slub.c

module: use strstarts()

2009-03-31T02:35:37Z

Impact: minor cleanup. I'm not going to neaten anyone else's code, but I'm happy to clean up my own. Signed-off-by: Rusty Russell

module: don't use stop_machine on module load

2009-03-31T02:35:35Z

Kay Sievers discovered that boot times are slowed by about half a second because all the stop_machine_create() calls, and he only probes about 40 modules (I have 125 loaded on this laptop). We only do stop_machine_create() so we can unlink the module if something goes wrong, but it's overkill (and buggy anyway: if stop_machine_create() fails we still call stop_machine_destroy()). Since we are only protecting against kallsyms (esp. oops) walking the list, synchronize_sched() is sufficient (synchronize_rcu() is probably sufficient, but we're not in a hurry). Kay says of this patch: ... no module takes more than 40 millisecs to link now, most of them are between 3 and 8 millisecs. That looks very different to the numbers without this patch and the otherwise same setup, where we get heavy noise in the traces and many delays of up to 200 millisecs until linking, most of them taking 30+ millisecs. Tested-by: Kay Sievers Signed-off-by: Rusty Russell

module: include other structures in module version check

2009-03-31T02:35:34Z

With CONFIG_MODVERSIONS, we version 'struct module' using a dummy export, but other things matter too: 1) 'struct modversion_info' determines the layout of the __versions section, 2) 'struct kernel_param' determines the layout of the __params section, 3) 'struct kernel_symbol' determines __ksymtab*. 4) 'struct marker' determines __markers. 5) 'struct tracepoint' determines __tracepoints. So we rename 'struct_module' to 'module_layout' and include these in the signature. Now it's general we can add others later on without confusion. Signed-off-by: Rusty Russell

module: remove the SHF_ALLOC flag on the __versions section.

2009-03-31T02:35:34Z

Impact: reduce kernel memory usage This patch just takes off the SHF_ALLOC flag on __versions so we don't keep them around after module load. This saves about 7% of module memory if CONFIG_MODVERSIONS=y. Cc: Shawn Bohrer Signed-off-by: Rusty Russell

module: clarify the force-loading taint message.

2009-03-31T02:35:33Z

Impact: Message cleanup Two of three callers of try_to_force_load() are not because of a missing version, so change the messages: Old: : no version for "magic" found: kernel tainted. New: : bad vermagic: kernel tainted. Old: : no version for "nocrc" found: kernel tainted. New: : no versions for exported symbols: kernel tainted. Old: : no version for "" found: kernel tainted. New: : : kernel tainted. Signed-off-by: Rusty Russell

module: Export symbols needed for Ksplice

2009-03-31T02:35:33Z

Impact: Expose some module.c symbols Ksplice uses several functions from module.c in order to resolve symbols and implement dependency handling. Calling these functions requires holding module_mutex, so it is exported. (This is just the module part of a bigger add-exports patch from Tim). Cc: Anders Kaseorg Cc: Jeff Arnold Signed-off-by: Tim Abbott Signed-off-by: Rusty Russell