diff options
| author | Paul Mundt <lethal@linux-sh.org> | 2010-05-25 16:16:40 +0900 |
|---|---|---|
| committer | Paul Mundt <lethal@linux-sh.org> | 2010-05-25 16:16:40 +0900 |
| commit | 8a37f520523df971bd3f926d8bd45ead37e857e8 (patch) | |
| tree | 762b79bb60c55ef320ec72fdf7c079fa14cb765b | |
| parent | e1f42ff4f06e5feaa57a22556ad977ef62164e14 (diff) | |
sh: handle early calls to return_address() when using dwarf unwinder.
The dwarf unwinder ties in to an early initcall, but it's possible that
return_address() calls will be made prior to that. This implements some
additional error handling in to the dwarf unwinder as well as an exit
path in the return_address() case to bail out if the unwinder hasn't come
up yet.
This fixes a NULL pointer deref in early boot when mempool_alloc() blows
up on the not-yet-ready mempool via dwarf_unwind_stack().
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
| -rw-r--r-- | arch/sh/kernel/dwarf.c | 19 | ||||
| -rw-r--r-- | arch/sh/kernel/return_address.c | 2 |
2 files changed, 19 insertions, 2 deletions
diff --git a/arch/sh/kernel/dwarf.c b/arch/sh/kernel/dwarf.c index 886d7d83ace3..49c09c7d5b77 100644 --- a/arch/sh/kernel/dwarf.c +++ b/arch/sh/kernel/dwarf.c @@ -49,6 +49,8 @@ static DEFINE_SPINLOCK(dwarf_fde_lock); static struct dwarf_cie *cached_cie; +static unsigned int dwarf_unwinder_ready; + /** * dwarf_frame_alloc_reg - allocate memory for a DWARF register * @frame: the DWARF frame whose list of registers we insert on @@ -582,6 +584,13 @@ struct dwarf_frame *dwarf_unwind_stack(unsigned long pc, unsigned long addr; /* + * If we've been called in to before initialization has + * completed, bail out immediately. + */ + if (!dwarf_unwinder_ready) + return NULL; + + /* * If we're starting at the top of the stack we need get the * contents of a physical register to get the CFA in order to * begin the virtual unwinding of the stack. @@ -1167,7 +1176,7 @@ void module_dwarf_cleanup(struct module *mod) */ static int __init dwarf_unwinder_init(void) { - int err; + int err = -ENOMEM; dwarf_frame_cachep = kmem_cache_create("dwarf_frames", sizeof(struct dwarf_frame), 0, @@ -1181,11 +1190,15 @@ static int __init dwarf_unwinder_init(void) mempool_alloc_slab, mempool_free_slab, dwarf_frame_cachep); + if (!dwarf_frame_pool) + goto out; dwarf_reg_pool = mempool_create(DWARF_REG_MIN_REQ, mempool_alloc_slab, mempool_free_slab, dwarf_reg_cachep); + if (!dwarf_reg_pool) + goto out; err = dwarf_parse_section(__start_eh_frame, __stop_eh_frame, NULL); if (err) @@ -1195,11 +1208,13 @@ static int __init dwarf_unwinder_init(void) if (err) goto out; + dwarf_unwinder_ready = 1; + return 0; out: printk(KERN_ERR "Failed to initialise DWARF unwinder: %d\n", err); dwarf_unwinder_cleanup(); - return -EINVAL; + return err; } early_initcall(dwarf_unwinder_init); diff --git a/arch/sh/kernel/return_address.c b/arch/sh/kernel/return_address.c index cbf1dd5372b2..5124aeb28c3f 100644 --- a/arch/sh/kernel/return_address.c +++ b/arch/sh/kernel/return_address.c @@ -24,6 +24,8 @@ void *return_address(unsigned int depth) struct dwarf_frame *tmp; tmp = dwarf_unwind_stack(ra, frame); + if (!tmp) + return NULL; if (frame) dwarf_free_frame(frame); |