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4994e387d7
The mmiotrace tracer is "special". The purpose is to help reverse engineer binary drivers by removing the memory allocated by the driver and when the driver goes to access it, a fault occurs, the mmiotracer will record what the driver was doing and then do the work on its behalf by single stepping through the process. But to achieve this ability, it must do some special things. One is it needs to grab a lock while in the breakpoint handler. This is considered an NMI state, and then lockdep warns that the lock is being held in both an NMI state (really a breakpoint handler) and also in normal context. As the breakpoint/NMI state only happens when the driver is accessing memory, there's no concern of a race condition against the setup and tear-down of mmiotracer. To make lockdep and mmiotrace work together, convert the locks used in the breakpoint handler into arch_spin_lock(). Link: https://lkml.kernel.org/r/20221206191229.656244029@goodmis.org Link: https://lore.kernel.org/lkml/20221201213126.620b7dd3@gandalf.local.home/ Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Karol Herbst <karolherbst@gmail.com> Cc: Pekka Paalanen <ppaalanen@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> |
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| .. | ||
| pat | ||
| amdtopology.c | ||
| cpu_entry_area.c | ||
| debug_pagetables.c | ||
| dump_pagetables.c | ||
| extable.c | ||
| fault.c | ||
| highmem_32.c | ||
| hugetlbpage.c | ||
| ident_map.c | ||
| init_32.c | ||
| init_64.c | ||
| init.c | ||
| iomap_32.c | ||
| ioremap.c | ||
| kasan_init_64.c | ||
| kaslr.c | ||
| kmmio.c | ||
| kmsan_shadow.c | ||
| maccess.c | ||
| Makefile | ||
| mem_encrypt_amd.c | ||
| mem_encrypt_boot.S | ||
| mem_encrypt_identity.c | ||
| mem_encrypt.c | ||
| mm_internal.h | ||
| mmap.c | ||
| mmio-mod.c | ||
| numa_32.c | ||
| numa_64.c | ||
| numa_emulation.c | ||
| numa_internal.h | ||
| numa.c | ||
| pf_in.c | ||
| pf_in.h | ||
| pgprot.c | ||
| pgtable_32.c | ||
| pgtable.c | ||
| physaddr.c | ||
| physaddr.h | ||
| pkeys.c | ||
| pti.c | ||
| srat.c | ||
| testmmiotrace.c | ||
| tlb.c | ||