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6f07048c00
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
107 lines
2.4 KiB
C
107 lines
2.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_SECTIONS_H
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#define _ASM_POWERPC_SECTIONS_H
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#ifdef __KERNEL__
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#include <linux/elf.h>
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#include <linux/uaccess.h>
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#define arch_is_kernel_initmem_freed arch_is_kernel_initmem_freed
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#include <asm-generic/sections.h>
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extern bool init_mem_is_free;
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static inline int arch_is_kernel_initmem_freed(unsigned long addr)
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{
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if (!init_mem_is_free)
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return 0;
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return addr >= (unsigned long)__init_begin &&
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addr < (unsigned long)__init_end;
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}
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extern char __head_end[];
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#ifdef __powerpc64__
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extern char __start_interrupts[];
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extern char __end_interrupts[];
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extern char __prom_init_toc_start[];
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extern char __prom_init_toc_end[];
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#ifdef CONFIG_PPC_POWERNV
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extern char start_real_trampolines[];
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extern char end_real_trampolines[];
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extern char start_virt_trampolines[];
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extern char end_virt_trampolines[];
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#endif
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static inline int in_kernel_text(unsigned long addr)
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{
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if (addr >= (unsigned long)_stext && addr < (unsigned long)__init_end)
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return 1;
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return 0;
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}
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static inline unsigned long kernel_toc_addr(void)
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{
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/* Defined by the linker, see vmlinux.lds.S */
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extern unsigned long __toc_start;
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/*
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* The TOC register (r2) points 32kB into the TOC, so that 64kB of
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* the TOC can be addressed using a single machine instruction.
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*/
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return (unsigned long)(&__toc_start) + 0x8000UL;
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}
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static inline int overlaps_interrupt_vector_text(unsigned long start,
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unsigned long end)
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{
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unsigned long real_start, real_end;
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real_start = __start_interrupts - _stext;
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real_end = __end_interrupts - _stext;
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return start < (unsigned long)__va(real_end) &&
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(unsigned long)__va(real_start) < end;
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}
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static inline int overlaps_kernel_text(unsigned long start, unsigned long end)
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{
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return start < (unsigned long)__init_end &&
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(unsigned long)_stext < end;
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}
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#ifdef PPC64_ELF_ABI_v1
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#define HAVE_DEREFERENCE_FUNCTION_DESCRIPTOR 1
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#undef dereference_function_descriptor
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static inline void *dereference_function_descriptor(void *ptr)
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{
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struct ppc64_opd_entry *desc = ptr;
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void *p;
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if (!probe_kernel_address(&desc->funcaddr, p))
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ptr = p;
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return ptr;
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}
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#undef dereference_kernel_function_descriptor
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static inline void *dereference_kernel_function_descriptor(void *ptr)
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{
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if (ptr < (void *)__start_opd || ptr >= (void *)__end_opd)
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return ptr;
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return dereference_function_descriptor(ptr);
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}
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#endif /* PPC64_ELF_ABI_v1 */
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#endif
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_SECTIONS_H */
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