hexdump: fix for non-aligned buffers (0f70fe60) · Commits · 戴 / test

A hexdump with a buf not aligned to the groupsize causes non-naturally-aligned memory accesses. This was causing a kernel panic on the processor BlackFin BF527, when such an unaligned buffer was fed by the function ubifs_scanned_corruption in fs/ubifs/scan.c . To fix this, change accesses to the contents of the buffer so they go through get_unaligned(). This change should be harmless to unaligned- access-capable architectures, and any performance hit should be anyway dwarfed by the snprintf() processing time. Signed-off-by:

Horacio Mijail Antón Quiles <hmijail@gmail.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: David Howells <dhowells@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Joe Perches <joe@perches.com> Acked-by:

Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

lib/hexdump.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -11,6 +11,7 @@
		#include <linux/ctype.h>
		#include <linux/kernel.h>
		#include <linux/export.h>
		#include <asm/unaligned.h>

		const char hex_asc[] = "0123456789abcdef";
		EXPORT_SYMBOL(hex_asc);
		@@ -139,7 +140,7 @@ int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
		for (j = 0; j < ngroups; j++) {
		ret = snprintf(linebuf + lx, linebuflen - lx,
		"%s%16.16llx", j ? " " : "",
		(unsigned long long)*(ptr8 + j));
		get_unaligned(ptr8 + j));
		if (ret >= linebuflen - lx)
		goto overflow1;
		lx += ret;
		@@ -150,7 +151,7 @@ int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
		for (j = 0; j < ngroups; j++) {
		ret = snprintf(linebuf + lx, linebuflen - lx,
		"%s%8.8x", j ? " " : "",
		*(ptr4 + j));
		get_unaligned(ptr4 + j));
		if (ret >= linebuflen - lx)
		goto overflow1;
		lx += ret;
		@@ -161,7 +162,7 @@ int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
		for (j = 0; j < ngroups; j++) {
		ret = snprintf(linebuf + lx, linebuflen - lx,
		"%s%4.4x", j ? " " : "",
		*(ptr2 + j));
		get_unaligned(ptr2 + j));
		if (ret >= linebuflen - lx)
		goto overflow1;
		lx += ret;

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