diff options
| author | Michael Ellerman <mpe@ellerman.id.au> | 2019-11-27 18:41:26 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-11-27 18:41:26 +1100 |
| commit | 6f07048c00fd100ed8cab66c225c157e0b6c0a50 (patch) | |
| tree | 051d6c22eea45269d5f65e1c00fd14bd60b79f7c | |
| parent | 8dcd71b45df34d9b903450fab147ee8c1e6c16b5 (diff) | |
powerpc: Define arch_is_kernel_initmem_freed() for lockdep
Under certain circumstances, we hit a warning in lockdep_register_key:
if (WARN_ON_ONCE(static_obj(key)))
return;
This occurs when the key falls into initmem that has since been freed
and can now be reused. This has been observed on boot, and under
memory pressure.
Define arch_is_kernel_initmem_freed(), which allows lockdep to
correctly identify this memory as dynamic.
This fixes a bug picked up by the powerpc64 syzkaller instance where
we hit the WARN via alloc_netdev_mqs.
Reported-by: Qian Cai <cai@lca.pw>
Reported-by: ppc syzbot c/o Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Daniel Axtens <dja@axtens.net>
Link: https://lore.kernel.org/r/87lfs4f7d6.fsf@dja-thinkpad.axtens.net
| -rw-r--r-- | arch/powerpc/include/asm/sections.h | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/sections.h b/arch/powerpc/include/asm/sections.h index 5a9b6eb651b6..d19871763ed4 100644 --- a/arch/powerpc/include/asm/sections.h +++ b/arch/powerpc/include/asm/sections.h @@ -5,8 +5,22 @@ #include <linux/elf.h> #include <linux/uaccess.h> + +#define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed + #include <asm-generic/sections.h> +extern bool init_mem_is_free; + +static inline int arch_is_kernel_initmem_freed(unsigned long addr) +{ + if (!init_mem_is_free) + return 0; + + return addr >= (unsigned long)__init_begin && + addr < (unsigned long)__init_end; +} + extern char __head_end[]; #ifdef __powerpc64__ |