https://github.com/torvalds/linux
Revision 9bea7f23952d5948f8e5dfdff4de09bb9981fb5f authored by Rusty Russell on 05 June 2010, 17:17:37 UTC, committed by Rusty Russell on 05 June 2010, 01:47:37 UTC
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>
1 parent be593f4
Tip revision: 9bea7f23952d5948f8e5dfdff4de09bb9981fb5f authored by Rusty Russell on 05 June 2010, 17:17:37 UTC
module: fix bne2 "gave up waiting for init of module libcrc32c"
module: fix bne2 "gave up waiting for init of module libcrc32c"
Tip revision: 9bea7f2
File | Mode | Size |
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Documentation | ||
arch | ||
block | ||
crypto | ||
drivers | ||
firmware | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.gitignore | -rw-r--r-- | 936 bytes |
.mailmap | -rw-r--r-- | 3.9 KB |
COPYING | -rw-r--r-- | 18.3 KB |
CREDITS | -rw-r--r-- | 91.8 KB |
Kbuild | -rw-r--r-- | 2.4 KB |
MAINTAINERS | -rw-r--r-- | 170.0 KB |
Makefile | -rw-r--r-- | 52.6 KB |
README | -rw-r--r-- | 17.0 KB |
REPORTING-BUGS | -rw-r--r-- | 3.3 KB |
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