rust/Kconfig: disable Rust support if CONFIG_MODVERSIONS=y #379
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In recent weeks, there have been a few reports of Rust build errors for defconfigs which have CONFIG_MODVERSIONS=y. See torvalds#378 for example. According to torvalds#59, Rust-for-Linux currently doesn't support MODVERSIONS. To prevent confusion and build errors in the future, disable Rust support if CONFIG_MODVERSIONS=y. Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com>
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intel-lab-lkp
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Jan 11, 2023
Currently modversion uses a fixed size array of size (64 - sizeof(long))
to store symbol names, thus placing a hard limit on length of symbols.
Rust symbols (which encodes crate and module names) can be quite a bit
longer. The length limit in kallsyms is increased to 512 for this reason.
It's a waste of space to simply expand the fixed array size to 512 in
modversion info entries. I therefore make it variably sized, with offset
to the next entry indicated by the initial "next" field.
In addition to supporting longer-than-56/60 byte symbols, this patch also
reduce the size for short symbols by getting rid of excessive 0 paddings.
There are still some zero paddings to ensure "next" and "crc" fields are
properly aligned.
This patch does have a tiny drawback that it makes ".mod.c" files generated
a bit less easy to read, as code like
"\x08\x00\x00\x00\x78\x56\x34\x12"
"symbol\0\0"
is generated as opposed to
{ 0x12345678, "symbol" },
because the structure is now variable-length. But hopefully nobody reads
the generated file :)
Link: b8a94bf ("kallsyms: increase maximum kernel symbol length to 512")
Link: Rust-for-Linux#379
Signed-off-by: Gary Guo <gary@garyguo.net>
tobhe
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to UbuntuAsahi/linux
that referenced
this pull request
May 15, 2023
BugLink: https://bugs.launchpad.net/bugs/2007654 Currently modversion uses a fixed size array of size (64 - sizeof(long)) to store symbol names, thus placing a hard limit on length of symbols. Rust symbols (which encodes crate and module names) can be quite a bit longer. The length limit in kallsyms is increased to 512 for this reason. It's a waste of space to simply expand the fixed array size to 512 in modversion info entries. I therefore make it variably sized, with offset to the next entry indicated by the initial "next" field. In addition to supporting longer-than-56/60 byte symbols, this patch also reduce the size for short symbols by getting rid of excessive 0 paddings. There are still some zero paddings to ensure "next" and "crc" fields are properly aligned. This patch does have a tiny drawback that it makes ".mod.c" files generated a bit less easy to read, as code like "\x08\x00\x00\x00\x78\x56\x34\x12" "symbol\0\0" is generated as opposed to { 0x12345678, "symbol" }, because the structure is now variable-length. But hopefully nobody reads the generated file :) Link: b8a94bf ("kallsyms: increase maximum kernel symbol length to 512") Link: Rust-for-Linux#379 Signed-off-by: Gary Guo <gary@garyguo.net> (backported from https://lore.kernel.org/lkml/20230111161155.1349375-1-gary@garyguo.net/) [ fix build error on s390x: always use a variable with TO_NATIVE() ] [ add dummy NULL entry at the end of the modversion array ] Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
tobhe
pushed a commit
to UbuntuAsahi/linux
that referenced
this pull request
Jun 12, 2023
BugLink: https://bugs.launchpad.net/bugs/2007654 Currently modversion uses a fixed size array of size (64 - sizeof(long)) to store symbol names, thus placing a hard limit on length of symbols. Rust symbols (which encodes crate and module names) can be quite a bit longer. The length limit in kallsyms is increased to 512 for this reason. It's a waste of space to simply expand the fixed array size to 512 in modversion info entries. I therefore make it variably sized, with offset to the next entry indicated by the initial "next" field. In addition to supporting longer-than-56/60 byte symbols, this patch also reduce the size for short symbols by getting rid of excessive 0 paddings. There are still some zero paddings to ensure "next" and "crc" fields are properly aligned. This patch does have a tiny drawback that it makes ".mod.c" files generated a bit less easy to read, as code like "\x08\x00\x00\x00\x78\x56\x34\x12" "symbol\0\0" is generated as opposed to { 0x12345678, "symbol" }, because the structure is now variable-length. But hopefully nobody reads the generated file :) Link: b8a94bf ("kallsyms: increase maximum kernel symbol length to 512") Link: Rust-for-Linux#379 Signed-off-by: Gary Guo <gary@garyguo.net> (backported from https://lore.kernel.org/lkml/20230111161155.1349375-1-gary@garyguo.net/) [ fix build error on s390x: always use a variable with TO_NATIVE() ] [ add dummy NULL entry at the end of the modversion array ] Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Joshua-Riek
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to Joshua-Riek/linux
that referenced
this pull request
Oct 24, 2023
BugLink: https://bugs.launchpad.net/bugs/2007654 Currently modversion uses a fixed size array of size (64 - sizeof(long)) to store symbol names, thus placing a hard limit on length of symbols. Rust symbols (which encodes crate and module names) can be quite a bit longer. The length limit in kallsyms is increased to 512 for this reason. It's a waste of space to simply expand the fixed array size to 512 in modversion info entries. I therefore make it variably sized, with offset to the next entry indicated by the initial "next" field. In addition to supporting longer-than-56/60 byte symbols, this patch also reduce the size for short symbols by getting rid of excessive 0 paddings. There are still some zero paddings to ensure "next" and "crc" fields are properly aligned. This patch does have a tiny drawback that it makes ".mod.c" files generated a bit less easy to read, as code like "\x08\x00\x00\x00\x78\x56\x34\x12" "symbol\0\0" is generated as opposed to { 0x12345678, "symbol" }, because the structure is now variable-length. But hopefully nobody reads the generated file :) Link: b8a94bf ("kallsyms: increase maximum kernel symbol length to 512") Link: Rust-for-Linux#379 Signed-off-by: Gary Guo <gary@garyguo.net> (backported from https://lore.kernel.org/lkml/20230111161155.1349375-1-gary@garyguo.net/) [ fix build error on s390x: always use a variable with TO_NATIVE() ] [ add dummy NULL entry at the end of the modversion array ] Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
arighi
pushed a commit
to arighi/sched_ext
that referenced
this pull request
Jan 10, 2024
BugLink: https://bugs.launchpad.net/bugs/2007654 Currently modversion uses a fixed size array of size (64 - sizeof(long)) to store symbol names, thus placing a hard limit on length of symbols. Rust symbols (which encodes crate and module names) can be quite a bit longer. The length limit in kallsyms is increased to 512 for this reason. It's a waste of space to simply expand the fixed array size to 512 in modversion info entries. I therefore make it variably sized, with offset to the next entry indicated by the initial "next" field. In addition to supporting longer-than-56/60 byte symbols, this patch also reduce the size for short symbols by getting rid of excessive 0 paddings. There are still some zero paddings to ensure "next" and "crc" fields are properly aligned. This patch does have a tiny drawback that it makes ".mod.c" files generated a bit less easy to read, as code like "\x08\x00\x00\x00\x78\x56\x34\x12" "symbol\0\0" is generated as opposed to { 0x12345678, "symbol" }, because the structure is now variable-length. But hopefully nobody reads the generated file :) Link: b8a94bf ("kallsyms: increase maximum kernel symbol length to 512") Link: Rust-for-Linux/linux#379 Signed-off-by: Gary Guo <gary@garyguo.net> (backported from https://lore.kernel.org/lkml/20230111161155.1349375-1-gary@garyguo.net/) [ fix build error on s390x: always use a variable with TO_NATIVE() ] [ add dummy NULL entry at the end of the modversion array ] Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
arighi
pushed a commit
to arighi/sched_ext
that referenced
this pull request
Jan 25, 2024
BugLink: https://bugs.launchpad.net/bugs/2007654 Currently modversion uses a fixed size array of size (64 - sizeof(long)) to store symbol names, thus placing a hard limit on length of symbols. Rust symbols (which encodes crate and module names) can be quite a bit longer. The length limit in kallsyms is increased to 512 for this reason. It's a waste of space to simply expand the fixed array size to 512 in modversion info entries. I therefore make it variably sized, with offset to the next entry indicated by the initial "next" field. In addition to supporting longer-than-56/60 byte symbols, this patch also reduce the size for short symbols by getting rid of excessive 0 paddings. There are still some zero paddings to ensure "next" and "crc" fields are properly aligned. This patch does have a tiny drawback that it makes ".mod.c" files generated a bit less easy to read, as code like "\x08\x00\x00\x00\x78\x56\x34\x12" "symbol\0\0" is generated as opposed to { 0x12345678, "symbol" }, because the structure is now variable-length. But hopefully nobody reads the generated file :) Link: b8a94bf ("kallsyms: increase maximum kernel symbol length to 512") Link: Rust-for-Linux/linux#379 Signed-off-by: Gary Guo <gary@garyguo.net> (backported from https://lore.kernel.org/lkml/20230111161155.1349375-1-gary@garyguo.net/) [ fix build error on s390x: always use a variable with TO_NATIVE() ] [ add dummy NULL entry at the end of the modversion array ] Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
arighi
pushed a commit
to arighi/sched_ext
that referenced
this pull request
Feb 4, 2024
BugLink: https://bugs.launchpad.net/bugs/2007654 Currently modversion uses a fixed size array of size (64 - sizeof(long)) to store symbol names, thus placing a hard limit on length of symbols. Rust symbols (which encodes crate and module names) can be quite a bit longer. The length limit in kallsyms is increased to 512 for this reason. It's a waste of space to simply expand the fixed array size to 512 in modversion info entries. I therefore make it variably sized, with offset to the next entry indicated by the initial "next" field. In addition to supporting longer-than-56/60 byte symbols, this patch also reduce the size for short symbols by getting rid of excessive 0 paddings. There are still some zero paddings to ensure "next" and "crc" fields are properly aligned. This patch does have a tiny drawback that it makes ".mod.c" files generated a bit less easy to read, as code like "\x08\x00\x00\x00\x78\x56\x34\x12" "symbol\0\0" is generated as opposed to { 0x12345678, "symbol" }, because the structure is now variable-length. But hopefully nobody reads the generated file :) Link: b8a94bf ("kallsyms: increase maximum kernel symbol length to 512") Link: Rust-for-Linux/linux#379 Signed-off-by: Gary Guo <gary@garyguo.net> (backported from https://lore.kernel.org/lkml/20230111161155.1349375-1-gary@garyguo.net/) [ fix build error on s390x: always use a variable with TO_NATIVE() ] [ add dummy NULL entry at the end of the modversion array ] Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
arighi
pushed a commit
to arighi/sched_ext
that referenced
this pull request
Feb 7, 2024
BugLink: https://bugs.launchpad.net/bugs/2007654 Currently modversion uses a fixed size array of size (64 - sizeof(long)) to store symbol names, thus placing a hard limit on length of symbols. Rust symbols (which encodes crate and module names) can be quite a bit longer. The length limit in kallsyms is increased to 512 for this reason. It's a waste of space to simply expand the fixed array size to 512 in modversion info entries. I therefore make it variably sized, with offset to the next entry indicated by the initial "next" field. In addition to supporting longer-than-56/60 byte symbols, this patch also reduce the size for short symbols by getting rid of excessive 0 paddings. There are still some zero paddings to ensure "next" and "crc" fields are properly aligned. This patch does have a tiny drawback that it makes ".mod.c" files generated a bit less easy to read, as code like "\x08\x00\x00\x00\x78\x56\x34\x12" "symbol\0\0" is generated as opposed to { 0x12345678, "symbol" }, because the structure is now variable-length. But hopefully nobody reads the generated file :) Link: b8a94bf ("kallsyms: increase maximum kernel symbol length to 512") Link: Rust-for-Linux/linux#379 Signed-off-by: Gary Guo <gary@garyguo.net> (backported from https://lore.kernel.org/lkml/20230111161155.1349375-1-gary@garyguo.net/) [ fix build error on s390x: always use a variable with TO_NATIVE() ] [ add dummy NULL entry at the end of the modversion array ] Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
arighi
pushed a commit
to arighi/sched_ext
that referenced
this pull request
Feb 7, 2024
BugLink: https://bugs.launchpad.net/bugs/2007654 Currently modversion uses a fixed size array of size (64 - sizeof(long)) to store symbol names, thus placing a hard limit on length of symbols. Rust symbols (which encodes crate and module names) can be quite a bit longer. The length limit in kallsyms is increased to 512 for this reason. It's a waste of space to simply expand the fixed array size to 512 in modversion info entries. I therefore make it variably sized, with offset to the next entry indicated by the initial "next" field. In addition to supporting longer-than-56/60 byte symbols, this patch also reduce the size for short symbols by getting rid of excessive 0 paddings. There are still some zero paddings to ensure "next" and "crc" fields are properly aligned. This patch does have a tiny drawback that it makes ".mod.c" files generated a bit less easy to read, as code like "\x08\x00\x00\x00\x78\x56\x34\x12" "symbol\0\0" is generated as opposed to { 0x12345678, "symbol" }, because the structure is now variable-length. But hopefully nobody reads the generated file :) Link: b8a94bf ("kallsyms: increase maximum kernel symbol length to 512") Link: Rust-for-Linux/linux#379 Signed-off-by: Gary Guo <gary@garyguo.net> (backported from https://lore.kernel.org/lkml/20230111161155.1349375-1-gary@garyguo.net/) [ fix build error on s390x: always use a variable with TO_NATIVE() ] [ add dummy NULL entry at the end of the modversion array ] Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
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In recent weeks, there have been a few reports of Rust build errors
for defconfigs which have CONFIG_MODVERSIONS=y. See #378 for example.
According to #59, Rust-for-Linux currently doesn't support MODVERSIONS.
To prevent confusion and build errors in the future, disable Rust
support if CONFIG_MODVERSIONS=y.
Signed-off-by: Sven Van Asbroeck thesven73@gmail.com