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| author | Rusty Russell <rusty@rustcorp.com.au> | 2005-08-01 21:11:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-08-01 21:38:01 -0700 |
| commit | 842bbaaa7394820c8f1fe0629cd15478653caf86 (patch) | |
| tree | 5934040b40357f479b16d638ffd2fe435f4837e8 | |
| parent | 561fb765b97f287211a2c73a844c5edb12f44f1d (diff) | |
| download | linux-3.10-842bbaaa7394820c8f1fe0629cd15478653caf86.tar.gz linux-3.10-842bbaaa7394820c8f1fe0629cd15478653caf86.tar.bz2 linux-3.10-842bbaaa7394820c8f1fe0629cd15478653caf86.zip | |
[PATCH] Module per-cpu alignment cannot always be met
The module code assumes noone will ever ask for a per-cpu area more than
SMP_CACHE_BYTES aligned. However, as these cases show, gcc asks sometimes
asks for 32-byte alignment for the per-cpu section on a module, and if
CONFIG_X86_L1_CACHE_SHIFT is 4, we hit that BUG_ON(). This is obviously an
unusual combination, as there have been few reports, but better to warn
than die.
See:
http://www.ussg.iu.edu/hypermail/linux/kernel/0409.0/0768.html
And more recently:
http://bugs.gentoo.org/show_bug.cgi?id=97006
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | kernel/module.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/kernel/module.c b/kernel/module.c index 068e271ab3a..c32995fbd8f 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -250,13 +250,18 @@ static inline unsigned int block_size(int val) /* Created by linker magic */ extern char __per_cpu_start[], __per_cpu_end[]; -static void *percpu_modalloc(unsigned long size, unsigned long align) +static void *percpu_modalloc(unsigned long size, unsigned long align, + const char *name) { unsigned long extra; unsigned int i; void *ptr; - BUG_ON(align > SMP_CACHE_BYTES); + if (align > SMP_CACHE_BYTES) { + printk(KERN_WARNING "%s: per-cpu alignment %li > %i\n", + name, align, SMP_CACHE_BYTES); + align = SMP_CACHE_BYTES; + } ptr = __per_cpu_start; for (i = 0; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) { @@ -348,7 +353,8 @@ static int percpu_modinit(void) } __initcall(percpu_modinit); #else /* ... !CONFIG_SMP */ -static inline void *percpu_modalloc(unsigned long size, unsigned long align) +static inline void *percpu_modalloc(unsigned long size, unsigned long align, + const char *name) { return NULL; } @@ -1644,7 +1650,8 @@ static struct module *load_module(void __user *umod, if (pcpuindex) { /* We have a special allocation for this section. */ percpu = percpu_modalloc(sechdrs[pcpuindex].sh_size, - sechdrs[pcpuindex].sh_addralign); + sechdrs[pcpuindex].sh_addralign, + mod->name); if (!percpu) { err = -ENOMEM; goto free_mod; |