| Message ID | 20241103125259.944399-1-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | modpost: fix input MODULE_DEVICE_TABLE() built for 64-bit on 32-bit host | expand |
On Sun, Nov 3, 2024 at 9:53 PM Masahiro Yamada <masahiroy@kernel.org> wrote: > > When building a 64-bit kernel on a 32-bit build host, incorrect > input MODULE_ALIAS() entries may be generated. > > For example, when compiling a 64-bit kernel with CONFIG_INPUT_MOUSEDEV=m > on a 64-bit build machine, you will get the correct output: > > $ grep MODULE_ALIAS drivers/input/mousedev.mod.c > MODULE_ALIAS("input:b*v*p*e*-e*1,*2,*k*110,*r*0,*1,*a*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*2,*k*r*8,*a*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*14A,*r*a*0,*1,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*145,*r*a*0,*1,*18,*1C,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*110,*r*a*0,*1,*m*l*s*f*w*"); > > However, building the same kernel on a 32-bit machine results in > incorrect output: > > $ grep MODULE_ALIAS drivers/input/mousedev.mod.c > MODULE_ALIAS("input:b*v*p*e*-e*1,*2,*k*110,*130,*r*0,*1,*a*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*2,*k*r*8,*a*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*14A,*16A,*r*a*0,*1,*20,*21,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*145,*165,*r*a*0,*1,*18,*1C,*20,*21,*38,*3C,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*110,*130,*r*a*0,*1,*20,*21,*m*l*s*f*w*"); > > A similar issue occurs with CONFIG_INPUT_JOYDEV=m. On a 64-bit build > machine, the output is: > > $ grep MODULE_ALIAS drivers/input/joydev.mod.c > MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*0,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*2,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*8,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*6,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*k*120,*r*a*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*k*130,*r*a*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*k*2C0,*r*a*m*l*s*f*w*"); > > However, on a 32-bit machine, the output is incorrect: > > $ grep MODULE_ALIAS drivers/input/joydev.mod.c > MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*0,*20,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*2,*22,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*8,*28,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*6,*26,*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*k*11F,*13F,*r*a*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*k*11F,*13F,*r*a*m*l*s*f*w*"); > MODULE_ALIAS("input:b*v*p*e*-e*1,*k*2C0,*2E0,*r*a*m*l*s*f*w*"); > > When building a 64-bit kernel, BITS_PER_LONG is defined as 64. However, > on a 32-bit build machine, the constant, 1L, has a 32-bit width. > Left-shifting this constant beyond 32 bits causes wraparound. > > The fix in commit e0e92632715f ("[PATCH] PATCH: 1 line 2.6.18 bugfix: > modpost-64bit-fix.patch") is incorrect; it only addresses cases where > a 64-bit kernel is built on a 64-bit build machine, overlooking cases > on a 32-bit build machine. > > Using 1ULL ensures a 64-bit width on both 32-bit and 64-bit machines, > avoiding the wraparound issue. > > Fixes: e0e92632715f ("[PATCH] PATCH: 1 line 2.6.18 bugfix: modpost-64bit-fix.patch") > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > --- Applied to linux-kbuild/fixes.
diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c index 16154449dde1..c4cc11aa558f 100644 --- a/scripts/mod/file2alias.c +++ b/scripts/mod/file2alias.c @@ -743,7 +743,7 @@ static void do_input(char *alias, for (i = min / BITS_PER_LONG; i < max / BITS_PER_LONG + 1; i++) arr[i] = TO_NATIVE(arr[i]); for (i = min; i < max; i++) - if (arr[i / BITS_PER_LONG] & (1L << (i%BITS_PER_LONG))) + if (arr[i / BITS_PER_LONG] & (1ULL << (i%BITS_PER_LONG))) sprintf(alias + strlen(alias), "%X,*", i); }
When building a 64-bit kernel on a 32-bit build host, incorrect input MODULE_ALIAS() entries may be generated. For example, when compiling a 64-bit kernel with CONFIG_INPUT_MOUSEDEV=m on a 64-bit build machine, you will get the correct output: $ grep MODULE_ALIAS drivers/input/mousedev.mod.c MODULE_ALIAS("input:b*v*p*e*-e*1,*2,*k*110,*r*0,*1,*a*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*2,*k*r*8,*a*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*14A,*r*a*0,*1,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*145,*r*a*0,*1,*18,*1C,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*110,*r*a*0,*1,*m*l*s*f*w*"); However, building the same kernel on a 32-bit machine results in incorrect output: $ grep MODULE_ALIAS drivers/input/mousedev.mod.c MODULE_ALIAS("input:b*v*p*e*-e*1,*2,*k*110,*130,*r*0,*1,*a*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*2,*k*r*8,*a*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*14A,*16A,*r*a*0,*1,*20,*21,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*145,*165,*r*a*0,*1,*18,*1C,*20,*21,*38,*3C,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*3,*k*110,*130,*r*a*0,*1,*20,*21,*m*l*s*f*w*"); A similar issue occurs with CONFIG_INPUT_JOYDEV=m. On a 64-bit build machine, the output is: $ grep MODULE_ALIAS drivers/input/joydev.mod.c MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*0,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*2,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*8,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*6,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*k*120,*r*a*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*k*130,*r*a*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*k*2C0,*r*a*m*l*s*f*w*"); However, on a 32-bit machine, the output is incorrect: $ grep MODULE_ALIAS drivers/input/joydev.mod.c MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*0,*20,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*2,*22,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*8,*28,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*3,*k*r*a*6,*26,*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*k*11F,*13F,*r*a*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*k*11F,*13F,*r*a*m*l*s*f*w*"); MODULE_ALIAS("input:b*v*p*e*-e*1,*k*2C0,*2E0,*r*a*m*l*s*f*w*"); When building a 64-bit kernel, BITS_PER_LONG is defined as 64. However, on a 32-bit build machine, the constant, 1L, has a 32-bit width. Left-shifting this constant beyond 32 bits causes wraparound. The fix in commit e0e92632715f ("[PATCH] PATCH: 1 line 2.6.18 bugfix: modpost-64bit-fix.patch") is incorrect; it only addresses cases where a 64-bit kernel is built on a 64-bit build machine, overlooking cases on a 32-bit build machine. Using 1ULL ensures a 64-bit width on both 32-bit and 64-bit machines, avoiding the wraparound issue. Fixes: e0e92632715f ("[PATCH] PATCH: 1 line 2.6.18 bugfix: modpost-64bit-fix.patch") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- scripts/mod/file2alias.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)