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On Thu, Oct 08, 2020 at 01:55:04PM -0400, John Covici wrote: |
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> modules.alias modules.builtin |
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> modules.builtin.bin modules.dep.bin modules.order |
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> modules.symbols |
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> modules.alias.bin modules.builtin.alias.bin modules.dep |
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> modules.devname modules.softdep |
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> modules.symbols.bin |
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|
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That's fine. |
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|
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> and the error message is |
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> |
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> lspci: Unable to load libkmod resources: error -12 |
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|
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That error message is printed by lspci [1], although it is the result of the |
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libkmod `kmod_load_resources` function returning less than zero [2]. With a -12 |
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error, this suggests a failing with the `index_mm_open` function [3]. It's quite |
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a beast of a function; the failure could be due to a multitude of reasons. |
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|
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Considering the nature of the error (memory allocation failure), I reckon it |
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must be either the following call to mmap(2), or the preceding call to open(2): |
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(paraphrasing for formatting): |
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|
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|
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if ((fd = open(filename, O_RDONLY|O_CLOEXEC)) < 0) { |
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DBG(ctx, "open(%s, O_RDONLY|O_CLOEXEC): %m\n", filename); |
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err = -errno; |
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goto fail_open; |
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} |
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|
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/* [...] */ |
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|
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if ( ( idx->mm = mmap ( NULL, st.st_size, PROT_READ, |
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MAP_PRIVATE, fd, 0 ) ) == MAP_FAILED) { |
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ERR(ctx, "mmap (NULL, %"PRIu64", PROT_READ, %d, " \ |
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"MAP_PRIVATE, 0 ): %m\n", st.st_size, fd); |
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err = -errno; |
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goto fail_nommap; |
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} |
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|
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I might you need to debug this on your machine, as I can't reproduce it myself. |
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You'll need to clone, recompile, and relink libkmod and pciutils with the |
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maximum debugging settings, to keep all symbols in the executable. I assume |
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you're using GCC, although I suspect the same should work with Clang. |
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|
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git clone both repos: [4] and [5]. |
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|
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libkmod: |
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- Save the old symlink, by renaming /lib64/libkmod.<version> to |
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something temporary, like libkmod.old. |
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- Execute ./autogen.sh to create a configure script. |
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- Run the configure script to enable maximum debugging: |
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./configure CFLAGS='-ggdb3' --prefix=/usr --sysconfdir=/etc \ |
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--libdir=/usr/lib64 --with-rootprefix= --with-rootlibdir=/lib64 |
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- Compile and install the shared objects (you need to be root): |
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make && make install |
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- Ensure the `make install` has recreated the major version symlink in |
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/lib64 to the new shared object file. |
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|
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pciutils: |
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- Compile; there is no need to install: |
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make CFLAGS="-ggdb3" |
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|
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Now you have an lspci executable which is linked with the new libkmod, just need |
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to attach a debugger, such as gdb, and break on the troublesome function: |
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|
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$ gdb ./lspci |
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Reading symbols from ./lspci... |
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(gdb) b index_mm_open |
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Function "index_mm_open" not defined. |
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Make breakpoint pending on future shared library load? (y or [n]) y |
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Breakpoint 1 (index_mm_open) pending. |
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(gdb) run -k |
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|
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... after a while, you'll encounter the first invocation of the troublemaker: |
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|
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Breakpoint 1, index_mm_open (ctx=0x555555583340, filename=0x7fffffffc920 |
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"/lib/modules/5.4.60-gentoo/modules.dep.bin", stamp=0x5555555833a0, |
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pidx=0x555555583378) at libkmod/libkmod-index.c:744 |
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|
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Before going any further, I want to confirm that `filename` does point to a |
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correct file? I doubt the open(2) call would fail with ENOMEM if the file was |
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invalid, although you never know. Assuming `filename` is valid, we can start |
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stepping through the function to determine which inner function is failing. My |
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bets are on mmap. |
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|
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Hope to hear from you soon. |
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|
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[1] https://git.kernel.org/pub/scm/utils/pciutils/pciutils.git/tree/ls-kernel.c#n42 |
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[2] https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git/tree/libkmod/libkmod.c#n842 |
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[3] https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git/tree/libkmod/libkmod-index.c#n742 |
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[4] git://git.kernel.org/pub/scm/utils/pciutils/pciutils.git |
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[5] git://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git |
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|
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-- |
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|
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Ashley Dixon |
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suugaku.co.uk |
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|
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2A9A 4117 |
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DA96 D18A |
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8A7B B0D2 |
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A30E BF25 |
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F290 A8AA |
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