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Data corruption issues were observed in tests which initiated a system crash/reset while accessing BTT devices. This problem is reproducible. The BTT driver calls pmem_rw_bytes() to update data in pmem devices. This interface calls __copy_user_nocache(), which uses non-temporal stores so that the stores to pmem are persistent. __copy_user_nocache() uses non-temporal stores when a request size is 8 bytes or larger (and is aligned by 8 bytes). The BTT driver updates the BTT map table, which entry size is 4 bytes. Therefore, updates to the map table entries remain cached, and are not written to pmem after a crash. Change __copy_user_nocache() to use non-temporal store when a request size is 4 bytes. The change extends the current byte-copy path for a less-than-8-bytes request, and does not add any overhead to the regular path. Reported-and-tested-by: Micah Parrish <micah.parrish@hpe.com> Reported-and-tested-by: Brian Boylston <brian.boylston@hpe.com> Signed-off-by: Toshi Kani <toshi.kani@hpe.com> Cc: <stable@vger.kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hp.com> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: linux-nvdimm@lists.01.org Link: http://lkml.kernel.org/r/1455225857-12039-3-git-send-email-toshi.kani@hpe.com [ Small readability edits. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| .. | ||
| .gitignore | ||
| atomic64_32.c | ||
| atomic64_386_32.S | ||
| atomic64_cx8_32.S | ||
| cache-smp.c | ||
| checksum_32.S | ||
| clear_page_64.S | ||
| cmdline.c | ||
| cmpxchg8b_emu.S | ||
| cmpxchg16b_emu.S | ||
| copy_page_64.S | ||
| copy_user_64.S | ||
| cpu.c | ||
| csum-copy_64.S | ||
| csum-partial_64.c | ||
| csum-wrappers_64.c | ||
| delay.c | ||
| getuser.S | ||
| inat.c | ||
| insn.c | ||
| iomap_copy_64.S | ||
| Makefile | ||
| memcpy_32.c | ||
| memcpy_64.S | ||
| memmove_64.S | ||
| memset_64.S | ||
| misc.c | ||
| mmx_32.c | ||
| msr-reg-export.c | ||
| msr-reg.S | ||
| msr-smp.c | ||
| msr.c | ||
| putuser.S | ||
| rwsem.S | ||
| string_32.c | ||
| strstr_32.c | ||
| usercopy_32.c | ||
| usercopy_64.c | ||
| usercopy.c | ||
| x86-opcode-map.txt | ||