user/sven/linux.git/kernel/module.c, branch v2.6.35.4

dynamic debug: move ddebug_remove_module() down into free_module()

2010-07-27T21:32:06Z

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 Reported-by: Thomas Renninger Tested-by: Thomas Renninger Cc: [2.6.32+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

module: initialize module dynamic debug later

2010-07-05T03:17:22Z

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 Signed-off-by: Rusty Russell (removed a #ifdef) Signed-off-by: Linus Torvalds

module: fix bne2 "gave up waiting for init of module libcrc32c"

2010-06-05T01:47:37Z

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 Cc: Linus Torvalds Cc: Tim Abbot Tested-by: Brandon Philips

module: verify_export_symbols under the lock

2010-06-05T01:47:37Z

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

module: move find_module check to end

2010-06-05T01:47:37Z

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

module: make locking more fine-grained.

2010-06-05T01:47:36Z

Kay Sievers 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 Cc: Brandon Philips Cc: Kay Sievers Cc: Linus Torvalds

module: Make module sysfs functions private.

2010-06-05T01:47:36Z

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 Cc: Randy Dunlap

module: move sysfs exposure to end of load_module

2010-06-05T01:47:36Z

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

module: fix kdb's illicit use of struct module_use.

2010-06-05T01:47:36Z

Linus changed the structure, and luckily this didn't compile any more. Reported-by: Stephen Rothwell Signed-off-by: Rusty Russell Cc: Jason Wessel Cc: Martin Hicks

module: Make the 'usage' lists be two-way

2010-06-05T01:47:35Z

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 Signed-off-by: Rusty Russell (cleaned & rebased)