March 2023 - Linux-stable-mirror

[for-linus][PATCH 1/5] tracing: Do not let histogram values have some modifiers

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Histogram values can not be strings, stacktraces, graphs, symbols, syscalls, or grouped in buckets or log. Give an error if a value is set to do so. Note, the histogram code was not prepared to handle these modifiers for histograms and caused a bug. Mark Rutland reported: # echo 'p:copy_to_user __arch_copy_to_user n=$arg2' >> /sys/kernel/tracing/kprobe_events # echo 'hist:keys=n:vals=hitcount.buckets=8:sort=hitcount' > /sys/kernel/tracing/events/kprobes/copy_to_user/trigger # cat /sys/kernel/tracing/events/kprobes/copy_to_user/hist [ 143.694628] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 [ 143.695190] Mem abort info: [ 143.695362] ESR = 0x0000000096000004 [ 143.695604] EC = 0x25: DABT (current EL), IL = 32 bits [ 143.695889] SET = 0, FnV = 0 [ 143.696077] EA = 0, S1PTW = 0 [ 143.696302] FSC = 0x04: level 0 translation fault [ 143.702381] Data abort info: [ 143.702614] ISV = 0, ISS = 0x00000004 [ 143.702832] CM = 0, WnR = 0 [ 143.703087] user pgtable: 4k pages, 48-bit VAs, pgdp=00000000448f9000 [ 143.703407] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000 [ 143.704137] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 143.704714] Modules linked in: [ 143.705273] CPU: 0 PID: 133 Comm: cat Not tainted 6.2.0-00003-g6fc512c10a7c #3 [ 143.706138] Hardware name: linux,dummy-virt (DT) [ 143.706723] pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 143.707120] pc : hist_field_name.part.0+0x14/0x140 [ 143.707504] lr : hist_field_name.part.0+0x104/0x140 [ 143.707774] sp : ffff800008333a30 [ 143.707952] x29: ffff800008333a30 x28: 0000000000000001 x27: 0000000000400cc0 [ 143.708429] x26: ffffd7a653b20260 x25: 0000000000000000 x24: ffff10d303ee5800 [ 143.708776] x23: ffffd7a6539b27b0 x22: ffff10d303fb8c00 x21: 0000000000000001 [ 143.709127] x20: ffff10d303ec2000 x19: 0000000000000000 x18: 0000000000000000 [ 143.709478] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [ 143.709824] x14: 0000000000000000 x13: 203a6f666e692072 x12: 6567676972742023 [ 143.710179] x11: 0a230a6d6172676f x10: 000000000000002c x9 : ffffd7a6521e018c [ 143.710584] x8 : 000000000000002c x7 : 7f7f7f7f7f7f7f7f x6 : 000000000000002c [ 143.710915] x5 : ffff10d303b0103e x4 : ffffd7a653b20261 x3 : 000000000000003d [ 143.711239] x2 : 0000000000020001 x1 : 0000000000000001 x0 : 0000000000000000 [ 143.711746] Call trace: [ 143.712115] hist_field_name.part.0+0x14/0x140 [ 143.712642] hist_field_name.part.0+0x104/0x140 [ 143.712925] hist_field_print+0x28/0x140 [ 143.713125] event_hist_trigger_print+0x174/0x4d0 [ 143.713348] hist_show+0xf8/0x980 [ 143.713521] seq_read_iter+0x1bc/0x4b0 [ 143.713711] seq_read+0x8c/0xc4 [ 143.713876] vfs_read+0xc8/0x2a4 [ 143.714043] ksys_read+0x70/0xfc [ 143.714218] __arm64_sys_read+0x24/0x30 [ 143.714400] invoke_syscall+0x50/0x120 [ 143.714587] el0_svc_common.constprop.0+0x4c/0x100 [ 143.714807] do_el0_svc+0x44/0xd0 [ 143.714970] el0_svc+0x2c/0x84 [ 143.715134] el0t_64_sync_handler+0xbc/0x140 [ 143.715334] el0t_64_sync+0x190/0x194 [ 143.715742] Code: a9bd7bfd 910003fd a90153f3 aa0003f3 (f9400000) [ 143.716510] ---[ end trace 0000000000000000 ]--- Segmentation fault Link: https://lkml.kernel.org/r/20230302020810.559462599@goodmis.org Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Andrew Morton <akpm(a)linux-foundation.org> Fixes: c6afad49d127f ("tracing: Add hist trigger 'sym' and 'sym-offset' modifiers") Reported-by: Mark Rutland <mark.rutland(a)arm.com> Tested-by: Mark Rutland <mark.rutland(a)arm.com> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/trace_events_hist.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 89877a18f933..6e8ab726a7b5 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -4235,6 +4235,15 @@ static int __create_val_field(struct hist_trigger_data *hist_data, goto out; } + /* Some types cannot be a value */ + if (hist_field->flags & (HIST_FIELD_FL_GRAPH | HIST_FIELD_FL_PERCENT | + HIST_FIELD_FL_BUCKET | HIST_FIELD_FL_LOG2 | + HIST_FIELD_FL_SYM | HIST_FIELD_FL_SYM_OFFSET | + HIST_FIELD_FL_SYSCALL | HIST_FIELD_FL_STACKTRACE)) { + hist_err(file->tr, HIST_ERR_BAD_FIELD_MODIFIER, errpos(field_str)); + ret = -EINVAL; + } + hist_data->fields[val_idx] = hist_field; ++hist_data->n_vals; -- 2.39.1

1 year, 10 months

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[PATCH] docs: add backporting and conflict resolution document

by Vegard Nossum

This is a new document based on my 2022 blog post: https://blogs.oracle.com/linux/post/backporting-patches-using-git Although this is aimed at stable contributors and distro maintainers, it does also contain useful tips and tricks for anybody who needs to resolve merge conflicts. By adding this to the kernel as documentation we can more easily point to it e.g. from stable emails about failed backports, as well as allow the community to modify it over time if necessary. I've added this under process/ since it also has process/applying-patches.rst. Another interesting document is maintainer/rebasing-and-merging.rst which maybe should eventually refer to this one, but I'm leaving that as a future cleanup. Thanks to Harshit for helping with the original blog post as well as this updated document. Cc: Harshit Mogalapalli <harshit.m.mogalapalli(a)oracle.com> Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Cc: Stephen Rothwell <sfr(a)canb.auug.org.au> Cc: Jason A. Donenfeld <Jason(a)zx2c4.com> Signed-off-by: Vegard Nossum <vegard.nossum(a)oracle.com> --- Documentation/process/backporting.rst | 488 ++++++++++++++++++++++++++ Documentation/process/index.rst | 1 + 2 files changed, 489 insertions(+) create mode 100644 Documentation/process/backporting.rst diff --git a/Documentation/process/backporting.rst b/Documentation/process/backporting.rst new file mode 100644 index 000000000000..1b03df759905 --- /dev/null +++ b/Documentation/process/backporting.rst @@ -0,0 +1,488 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================================== +Backporting and conflict resolution +=================================== + +:Author: Vegard Nossum <vegard.nossum(a)oracle.com> + +.. contents:: + :local: + :depth: 3 + :backlinks: none + +Introduction +============ + +Some developers may never really have to deal with backporting patches, +merging branches, or resolving conflicts in their day-to-day work, so +when a merge conflict does pop up, it can be daunting. Luckily, +resolving conflicts is a skill like any other, and there are many useful +techniques you can use to make the process smoother and increase your +confidence in the result. + +This document aims to be a comprehensive, step-by-step guide to +backporting and conflict resolution. + +Applying the patch to a tree +============================ + +Sometimes the patch you are backporting already exists as a git commit, +in which case you just cherry-pick it directly using +``git cherry-pick``. However, if the patch comes from an email, as it +often does for the Linux kernel, you will need to apply it to a tree +using ``git am``. + +If you've ever used ``git am``, you probably already know that it is +quite picky about the patch applying perfectly to your source tree. In +fact, you've probably had nightmares about ``.rej`` files and trying to +edit the patch to make it apply. + +It is strongly recommended to instead find an appropriate base version +where the patch applies cleanly and *then* cherry-pick it over to your +destination tree, as this will make git output conflict markers and let +you resolve conflicts with the help of git and any other conflict +resolution tools you might prefer to use. + +It's generally better to use the exact same base as the one the patch +was generated from, but it doesn't really matter that much as long as it +applies cleanly and isn't too far from the original base. The only +problem with applying the patch to the "wrong" base is that it may pull +in more unrelated changes in the context of the diff when cherry-picking +it to the older branch. + +If you are using +`b4 <https://people.kernel.org/monsieuricon/introducing-b4-and-patch-attestation>`__ +and you are applying the patch directly from an email, you can use +``b4 am`` with the options ``-g``/``--guess-base`` and +``-3``/``--prep-3way`` to do some of this automatically (see `this +presentation <https://youtu.be/mF10hgVIx9o?t=2996>`__ for more +information). However, the rest of this article will assume that you are +doing a plain ``git cherry-pick``. + +Once you have the patch in git, you can go ahead and cherry-pick it into +your source tree. Don't forget to cherry-pick with ``-x`` if you want a +written record of where the patch came from! + +Resolving conflicts +=================== + +Uh-oh; the cherry-pick failed with a vaguely threatening message:: + + CONFLICT (content): Merge conflict + +What to do now? + +In general, conflicts appear when the context of the patch (i.e., the +lines being changed and/or the lines surrounding the changes) doesn't +match what's in the tree you are trying to apply the patch *to*. + +For backports, what likely happened was that your older branch is +missing a patch compared to the branch you are backporting from -- +however, it is also possible that your older branch has some commit that +doesn't exist in the newer branch. In any case, the result is a conflict +that needs to be resolved. + +If your attempted cherry-pick fails with a conflict, git automatically +edits the files to include so-called conflict markers showing you where +the conflict is and how the two branches have diverged. Resolving the +conflict typically means editing the end result in such a way that it +takes into account these other commits. + +Resolving the conflict can be done either by hand in a regular text +editor or using a dedicated conflict resolution tool. + +Many people prefer to use their regular text editor and edit the +conflict directly, as it may be easier to understand what you're doing +and to control the final result. There are definitely pros and cons to +each method, and sometimes there's value in using both. + +We will not cover using dedicated merge tools here beyond providing some +pointers to various tools that you could use: + +- `vimdiff/gvimdiff <https://linux.die.net/man/1/vimdiff>`__ +- `KDiff3 <http://kdiff3.sourceforge.net/>`__ +- `TortoiseMerge <https://tortoisesvn.net/TortoiseMerge.html>`__ +- `Meld <https://meldmerge.org/help/>`__ +- `P4Merge <https://www.perforce.com/products/helix-core-apps/merge-diff-tool-p4merge>`__ +- `Beyond Compare <https://www.scootersoftware.com/>`__ +- `IntelliJ <https://www.jetbrains.com/help/idea/resolve-conflicts.html>`__ +- `VSCode <https://code.visualstudio.com/docs/editor/versioncontrol>`__ + +To configure git to work with these, see ``git mergetool --help`` or +`the official git documentation <https://git-scm.com/docs/git-mergetool>`__. + +Prerequisite patches +~~~~~~~~~~~~~~~~~~~~ + +Most conflicts happen because the branch you are backporting to is +missing some patches compared to the branch you are backporting *from*. +In the more general case (such as merging two independent branches), +development could have happened on either branch, or the branches have +simply diverged -- perhaps your older branch had some other backports +applied to it that themselves needed conflict resolutions, causing a +divergence. + +It's important to always identify the commit or commits that caused the +conflict, as otherwise you cannot be confident in the correctness of +your resolution. As an added bonus, especially if the patch is in an +area you're not that famliar with, the changelogs of these commits will +often give you the context to understand the code and potential problems +or pitfalls with your conflict resolution. + +git log +^^^^^^^ + +A good first step is to look at ``git log`` for the file that has the +conflict -- this is usually sufficient when there aren't a lot of +patches to the file, but may get confusing if the file is big and +frequently patched. You should run ``git log`` on the range of commits +between your currently checked-out branch (``HEAD``) and the parent of +the patch you are picking (``COMMIT``), i.e.:: + + git log HEAD..COMMIT^ -- PATH + +Even better, if you want to restrict this output to a single function +(because that's where the conflict appears), you can use the following +syntax:: + + git log -L:'\<function\>':PATH HEAD..COMMIT^ + +.. note:: + The ``\<`` and ``\>`` around the function name ensure that the + matches are anchored on a word boundary. This is important, as this + part is actually a regex and git only follows the first match, so + if you use ``-L:thread_stack:kernel/fork.c`` it may only give you + results for the function ``try_release_thread_stack_to_cache`` even + though there are many other functions in that file containing the + string ``thread_stack`` in their names. + +Another useful option for ``git log`` is ``-G``, which allows you to +filter on certain strings appearing in the diffs of the commits you are +listing:: + + git log -G'regex' HEAD..COMMIT^ -- PATH + +This can also be a handy way to quickly find when something (e.g. a +function call or a variable) was changed, added, or removed. The search +string is a regular expression, which means you can potentially search +for more specific things like assignments to a specific struct member:: + + git log -G'\->index\>.*=' + +git blame +^^^^^^^^^ + +Another way to find prerequisite commits (albeit only the most recent +one for a given conflict) is to run ``git blame``. In this case, you +need to run it against the parent commit of the patch you are +cherry-picking and the file where the conflict appared, i.e.:: + + git blame COMMIT^ -- PATH + +This command also accepts the ``-L`` argument (for restricting the +output to a single function), but in this case you specify the filename +at the end of the command as usual:: + + git blame -L:'\<function\>' COMMIT^ -- PATH + +Navigate to the place where the conflict occurred. The first column of +the blame output is the commit ID of the patch that added a given line +of code. + +It might be a good idea to ``git show`` these commits and see if they +look like they might be the source of the conflict. Sometimes there will +be more than one of these commits, either because multiple commits +changed different lines of the same conflict area *or* because multiple +subsequent patches changed the same line (or lines) multiple times. In +the latter case, you may have to run ``git blame`` again and specify the +older version of the file to look at in order to dig further back in +the history of the file. + +Prerequisite vs. incidental patches +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +Having found the patch that caused the conflict, you need to determine +whether it is a prerequisite for the patch you are backporting or +whether it is just incidental and can be skipped. An incidental patch +would be one that touches the same code as the patch you are +backporting, but does not change the semantics of the code in any +material way. For example, a whitespace cleanup patch is completely +incidental -- likewise, a patch that simply renames a function or a +variable would be incidental as well. On the other hand, if the function +being changed does not even exist in your current branch then this would +not be incidental at all and you need to carefully consider whether the +patch adding the function should be cherry-picked first. + +If you find that there is a necessary prerequisite patch, then you need +to stop and cherry-pick that instead. If you've already resolved some +conflicts in a different file and don't want to do it again, you can +create a temporary copy of that file. + +To abort the current cherry-pick, go ahead and run +``git cherry-pick --abort``, then restart the cherry-picking process +with the commit ID of the prerequisite patch instead. + +Understanding conflict markers +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Combined diffs +^^^^^^^^^^^^^^ + +Let's say you've decided against picking (or reverting) additional +patches and you just want to resolve the conflict. Git will have +inserted conflict markers into your file. Out of the box, this will look +something like:: + + <<<<<<< HEAD + this is what's in your current tree before cherry-picking + ======= + this is what the patch wants it to be after cherry-picking + >>>>>>> COMMIT... title + +This is what you would see if you opened the file in your editor. +However, if you were to run run ``git diff`` without any arguments, the +output would look something like this:: + + $ git diff + [...] + ++<<<<<<<< HEAD + +this is what's in your current tree before cherry-picking + ++======== + + this is what the patch wants it to be after cherry-picking + ++>>>>>>>> COMMIT... title + +When you are resolving a conflict, the behavior of ``git diff`` differs +from its normal behavior. Notice the two columns of diff markers +instead of the usual one; this is a so-called "`combined diff +<https://git-scm.com/docs/diff-format#_combined_diff_format>`__", here +showing the 3-way diff (or diff-of-diffs) between + +#. the current branch (before cherry-picking) and the current working + directory, and +#. the current branch (before cherry-picking) and the file as it looks + after the original patch has been applied. + +Better diffs +^^^^^^^^^^^^ + +3-way combined diffs include all the other changes that happened to the +file between your current branch and the branch you are cherry-picking +from. While this is useful for spotting other changes that you need to +take into account, this also makes the output of ``git diff`` somewhat +intimidating and difficult to read. You may instead prefer to run +``git diff HEAD`` (or ``git diff --ours``) which shows only the diff +between the current branch before cherry-picking and the current working +directory. It looks like this:: + + $ git diff HEAD + [...] + +<<<<<<<< HEAD + this is what's in your current tree before cherry-picking + +======== + +this is what the patch wants it to be after cherry-picking + +>>>>>>>> COMMIT... title + +As you can see, this reads just like any other diff and makes it clear +which lines are in the current branch and which lines are being added +because they are part of the merge conflict or the patch being +cherry-picked. + +Merge styles and diff3 +^^^^^^^^^^^^^^^^^^^^^^ + +The default conflict marker style shown above is known as the ``merge`` +style. There is also another style available, known as the ``diff3`` +style, which looks like this:: + + <<<<<<< HEAD + this is what is in your current tree before cherry-picking + ||||||| parent of COMMIT (title) + this is what the patch expected to find there + ======= + this is what the patch wants it to be after being applied + >>>>>>> COMMIT (title) + +As you can see, this has 3 parts instead of 2, and includes what git +expected to find there but didn't. Some people vastly prefer this style +as it makes it much clearer what the patch actually changed; i.e., it +allows you to compare the before-and-after versions of the file for the +commit you are cherry-picking. This allows you to make better decisions +about how to resolve the conflict. + +To change conflict marker styles, you can use the following command:: + + git config merge.conflictStyle diff3 + +There is a third option, ``zdiff3``, introduced in `Git +2.35 <https://github.blog/2022-01-24-highlights-from-git-2-35/>`__, +which has the same 3 sections as ``diff3``, but where common lines have +been trimmed off, making the conflict area smaller in some cases. + +Iterating on conflict resolutions +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +The first step in any conflict resolution process is to understand the +patch you are backporting. For the Linux kernel this is especially +important, since an incorrect change can lead to the whole system +crashing -- or worse, an undetected security vulnerability. + +Understanding the patch can be easy or difficult depending on the patch +itself, the changelog, and your familiarity with the code being changed. +However, a good question for every change (or every hunk of the patch) +might be: "Why is this hunk in the patch?" The answers to these +questions will inform your conflict resolution. + +Resolution process +^^^^^^^^^^^^^^^^^^ + +Sometimes the easiest thing to do is to just remove all but the first +part of the conflict, leaving the file essentially unchanged, and apply +the changes by hand. Perhaps the patch is changing a function call +argument from ``0`` to ``1`` while a conflicting change added an +entirely new (and insignificant) parameter to the end of the parameter +list; in that case, it's easy enough to change the argument from ``0`` +to ``1`` by hand and leave the rest of the arguments alone. This +technique of manually applying changes is mostly useful if the conflict +pulled in a lot of unrelated context that you don't really need to care +about. + +For particularly nasty conflicts with many conflict markers, you can use +``git add`` or ``git add -i`` to selectively stage your resolutions to +get them out of the way; this also lets you use ``git diff HEAD`` to +always see what remains to be resolved or ``git diff --cached`` to see +what your patch looks like so far. + +Function arguments +^^^^^^^^^^^^^^^^^^ + +Pay attention to changing function arguments! It's easy to gloss over +details and think that two lines are the same but actually they differ +in some small detail like which variable was passed as an argument +(especially if the two variables are both a single character that look +the same, like i and j). + +Error handling +^^^^^^^^^^^^^^ + +If you cherry-pick a patch that includes a ``goto`` statement (typically +for error handling), it is absolutely imperative to double check that +the target label is still correct in the branch you are backporting to. +Error handling is typically located at the bottom of the function, so it +may not be part of the conflict even though could have been changed by +other patches. + +A good way to ensure that you review the error paths is to always use +``git diff -W`` and ``git show -W`` (AKA ``--function-context``) when +inspecting your changes. For C code, this will show you the whole +function that's being changed in a patch. One of the things that often +go wrong during backports is that something else in the function changed +on either of the branches that you're backporting from or to. By +including the whole function in the diff you get more context and can +more easily spot problems that might otherwise go unnoticed. + +Dealing with file renames +^^^^^^^^^^^^^^^^^^^^^^^^^ + +One of the most annoying things that can happen while backporting a +patch is discovering that one of the files being patched has been +renamed, as that typically means git won't even put in conflict markers, +but will just throw up its hands and say (paraphrased): "Unmerged path! +You do the work..." + +There are generally a few ways to deal with this. If the patch to the +renamed file is small, like a one-line change, the easiest thing is to +just go ahead and apply the change by hand and be done with it. On the +other hand, if the change is big or complicated, you definitely don't +want to do it by hand. + +Sometimes the right thing to do will be to also backport the patch that +did the rename, but that's definitely not the most common case. Instead, +what you can do is to temporarily rename the file in the branch you're +backporting to (using ``git mv`` and committing the result), restart the +attempt to cherry-pick the patch, rename the file back (``git mv`` and +committing again), and finally squash the result using ``git rebase -i`` +(`tutorial <https://medium.com/@slamflipstrom/a-beginners-guide-to-squashing-commits-wi…>`__) +so it appears as a single commit when you are done. + +Verifying the result +==================== + +colordiff +~~~~~~~~~ + +Having committed a conflict-free new patch, you can now compare your +patch to the original patch. It is highly recommended that you use a +tool such as `colordiff <https://www.colordiff.org/>`__ that can show +two files side by side and color them according to the changes between +them:: + + colordiff -yw -W 200 <(git diff -W UPSTREAM_COMMIT^-) <(git diff -W HEAD^-) | less -SR + +Here, ``-y`` means to do a side-by-side comparison; ``-w`` ignores +whitespace, and ``-W 200`` sets the width of the output (as otherwise it +will use 130 by default, which is often a bit too little). + +The ``rev^-`` syntax is a handy shorthand for ``rev^..rev``, essentially +giving you just the diff for that single commit; also see +`the official git documentation <https://git-scm.com/docs/git-rev-parse#_other_rev_parent_shorthand_notations>`__. + +Again, note the inclusion of ``-W`` for ``git diff``; this ensures that +you will see the full function for any function that has changed. + +One incredibly important thing that colordiff does is to highlight lines +that are different. For example, if an error-handling ``goto`` has +changed labels between the original and backported patch, colordiff will +show these side-by-side but highlighted in a different color. Thus, it +is easy to see that the two ``goto`` statements are jumping to different +labels. Likewise, lines that were not modified by either patch but +differ in the context will also be highlighted and thus stand out during +a manual inspection. + +Of course, this is just a visual inspection; the real test is building +and running the patched kernel (or program). + +Build testing +~~~~~~~~~~~~~ + +We won't cover runtime testing here, but it can be a good idea to build +just the files touched by the patch as a quick sanity check. For the +Linux kernel you can build single files like this, assuming you have the +``.config`` and build environment set up correctly:: + + make path/to/file.o + +Note that this won't discover linker errors, so you should still do a +full build after verifying that the single file compiles. By compiling +the single file first you can avoid having to wait for a full build *in +case* there are compiler errors in any of the files you've changed. + +Runtime testing +~~~~~~~~~~~~~~~ + +Even a successful build or boot test is not necessarily enough to rule +out a missing dependency somewhere. Even though the chances are small, +there could be code changes where two independent changes to the same +file result in no conflicts, no compile-time errors, and runtime errors +only in exceptional cases. + +One concrete example of this was where a patch to the system call entry +code saved/restored a register and a later patch made use of the saved +register somewhere in the middle -- since there was no conflict, one +could backport the second patch and believe that everything was fine, +but in fact the code was now scribbling over an unsaved register. + +Although the vast majority of errors will be caught during compilation +or by superficially exercising the code, the only way to *really* verify +a backport is to review the final patch with the same level of scrutiny +as you would (or should) give to any other patch. Having unit tests and +regression tests or other types of automatic testing can help increase +the confidence in the correctness of a backport. + +Examples +======== + +The above shows roughly the idealized process of backporting a patch. +For a more concrete example, see this video tutorial where two patches +are backported from mainline to stable: +`Backporting Linux Kernel patches <https://youtu.be/sBR7R1V2FeA>`__ diff --git a/Documentation/process/index.rst b/Documentation/process/index.rst index d4b6217472b0..6eb6dcf9545e 100644 --- a/Documentation/process/index.rst +++ b/Documentation/process/index.rst @@ -58,6 +58,7 @@ lack of a better place. :maxdepth: 1 applying-patches + backporting adding-syscalls magic-number volatile-considered-harmful -- 2.35.1.46.g38062e73e0

1 year, 10 months

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[PATCH] drm/amdgpu: Don't resume IOMMU after incomplete init

by Felix Kuehling

Check kfd->init_complete in kgd2kfd_iommu_resume, consistent with other kgd2kfd calls. This should fix IOMMU errors on resume from suspend when KFD IOMMU initialization failed. Link: https://bugzilla.kernel.org/show_bug.cgi?id=217170 Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2454 Cc: Vasant Hegde <vasant.hegde(a)amd.com> Cc: Linux regression tracking (Thorsten Leemhuis) <regressions(a)leemhuis.info> Cc: stable(a)vger.kernel.org Signed-off-by: Felix Kuehling <Felix.Kuehling(a)amd.com> --- drivers/gpu/drm/amd/amdkfd/kfd_device.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device.c b/drivers/gpu/drm/amd/amdkfd/kfd_device.c index 521dfa88aad8..989c6aa2620b 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_device.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device.c @@ -60,6 +60,7 @@ static int kfd_gtt_sa_init(struct kfd_dev *kfd, unsigned int buf_size, unsigned int chunk_size); static void kfd_gtt_sa_fini(struct kfd_dev *kfd); +static int kfd_resume_iommu(struct kfd_dev *kfd); static int kfd_resume(struct kfd_dev *kfd); static void kfd_device_info_set_sdma_info(struct kfd_dev *kfd) @@ -625,7 +626,7 @@ bool kgd2kfd_device_init(struct kfd_dev *kfd, svm_migrate_init(kfd->adev); - if (kgd2kfd_resume_iommu(kfd)) + if (kfd_resume_iommu(kfd)) goto device_iommu_error; if (kfd_resume(kfd)) @@ -773,6 +774,14 @@ int kgd2kfd_resume(struct kfd_dev *kfd, bool run_pm) } int kgd2kfd_resume_iommu(struct kfd_dev *kfd) +{ + if (!kfd->init_complete) + return 0; + + return kfd_resume_iommu(kfd); +} + +static int kfd_resume_iommu(struct kfd_dev *kfd) { int err = 0; -- 2.34.1

1 year, 10 months

2
1
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[PATCH] KVM: arm64: Retry fault if vma_lookup() results become invalid

by David Matlack

Read mmu_invalidate_seq before dropping the mmap_lock so that KVM can detect if the results of vma_lookup() (e.g. vma_shift) become stale before it acquires kvm->mmu_lock. This fixes a theoretical bug where a VMA could be changed by userspace after vma_lookup() and before KVM reads the mmu_invalidate_seq, causing KVM to install page table entries based on a (possibly) no-longer-valid vma_shift. Re-order the MMU cache top-up to earlier in user_mem_abort() so that it is not done after KVM has read mmu_invalidate_seq (i.e. so as to avoid inducing spurious fault retries). This bug has existed since KVM/ARM's inception. It's unlikely that any sane userspace currently modifies VMAs in such a way as to trigger this race. And even with directed testing I was unable to reproduce it. But a sufficiently motivated host userspace might be able to exploit this race. Fixes: 94f8e6418d39 ("KVM: ARM: Handle guest faults in KVM") Cc: stable(a)vger.kernel.org Reported-by: Sean Christopherson <seanjc(a)google.com> Signed-off-by: David Matlack <dmatlack(a)google.com> --- arch/arm64/kvm/mmu.c | 48 +++++++++++++++++++------------------------- 1 file changed, 21 insertions(+), 27 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 7113587222ff..f54408355d1d 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1217,6 +1217,20 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, return -EFAULT; } + /* + * Permission faults just need to update the existing leaf entry, + * and so normally don't require allocations from the memcache. The + * only exception to this is when dirty logging is enabled at runtime + * and a write fault needs to collapse a block entry into a table. + */ + if (fault_status != ESR_ELx_FSC_PERM || + (logging_active && write_fault)) { + ret = kvm_mmu_topup_memory_cache(memcache, + kvm_mmu_cache_min_pages(kvm)); + if (ret) + return ret; + } + /* * Let's check if we will get back a huge page backed by hugetlbfs, or * get block mapping for device MMIO region. @@ -1269,37 +1283,17 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, fault_ipa &= ~(vma_pagesize - 1); gfn = fault_ipa >> PAGE_SHIFT; - mmap_read_unlock(current->mm); - - /* - * Permission faults just need to update the existing leaf entry, - * and so normally don't require allocations from the memcache. The - * only exception to this is when dirty logging is enabled at runtime - * and a write fault needs to collapse a block entry into a table. - */ - if (fault_status != ESR_ELx_FSC_PERM || - (logging_active && write_fault)) { - ret = kvm_mmu_topup_memory_cache(memcache, - kvm_mmu_cache_min_pages(kvm)); - if (ret) - return ret; - } - mmu_seq = vcpu->kvm->mmu_invalidate_seq; /* - * Ensure the read of mmu_invalidate_seq happens before we call - * gfn_to_pfn_prot (which calls get_user_pages), so that we don't risk - * the page we just got a reference to gets unmapped before we have a - * chance to grab the mmu_lock, which ensure that if the page gets - * unmapped afterwards, the call to kvm_unmap_gfn will take it away - * from us again properly. This smp_rmb() interacts with the smp_wmb() - * in kvm_mmu_notifier_invalidate_<page|range_end>. + * Read mmu_invalidate_seq so that KVM can detect if the results of + * vma_lookup() or __gfn_to_pfn_memslot() become stale prior to + * acquiring kvm->mmu_lock. * - * Besides, __gfn_to_pfn_memslot() instead of gfn_to_pfn_prot() is - * used to avoid unnecessary overhead introduced to locate the memory - * slot because it's always fixed even @gfn is adjusted for huge pages. + * Rely on mmap_read_unlock() for an implicit smp_rmb(), which pairs + * with the smp_wmb() in kvm_mmu_invalidate_end(). */ - smp_rmb(); + mmu_seq = vcpu->kvm->mmu_invalidate_seq; + mmap_read_unlock(current->mm); pfn = __gfn_to_pfn_memslot(memslot, gfn, false, false, NULL, write_fault, &writable, NULL); base-commit: 96a4627dbbd48144a65af936b321701c70876026 -- 2.40.0.rc1.284.g88254d51c5-goog

1 year, 10 months

3
3
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[PATCH AUTOSEL 6.2 01/16] clk: qcom: mmcc-apq8084: remove spdm clocks

by Sasha Levin

From: Dmitry Baryshkov <dmitry.baryshkov(a)linaro.org> [ Upstream commit 7b347f4b677b6d84687e67d82b6b17c6f55ea2b4 ] SPDM is used for debug/profiling and does not have any other functionality. These clocks can safely be removed. Suggested-by: Stephen Boyd <sboyd(a)kernel.org> Suggested-by: Georgi Djakov <djakov(a)kernel.org> Reviewed-by: Konrad Dybcio <konrad.dybcio(a)linaro.org> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov(a)linaro.org> Signed-off-by: Bjorn Andersson <andersson(a)kernel.org> Link: https://lore.kernel.org/r/20230111060402.1168726-11-dmitry.baryshkov@linaro… Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- drivers/clk/qcom/mmcc-apq8084.c | 271 -------------------------------- 1 file changed, 271 deletions(-) diff --git a/drivers/clk/qcom/mmcc-apq8084.c b/drivers/clk/qcom/mmcc-apq8084.c index e9f9713591558..025e21793b3c4 100644 --- a/drivers/clk/qcom/mmcc-apq8084.c +++ b/drivers/clk/qcom/mmcc-apq8084.c @@ -2364,262 +2364,6 @@ static struct clk_branch mmss_rbcpr_clk = { }, }; -static struct clk_branch mmss_spdm_ahb_clk = { - .halt_reg = 0x0230, - .clkr = { - .enable_reg = 0x0230, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_ahb_clk", - .parent_names = (const char *[]){ - "mmss_spdm_ahb_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_axi_clk = { - .halt_reg = 0x0210, - .clkr = { - .enable_reg = 0x0210, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_axi_clk", - .parent_names = (const char *[]){ - "mmss_spdm_axi_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_csi0_clk = { - .halt_reg = 0x023c, - .clkr = { - .enable_reg = 0x023c, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_csi0_clk", - .parent_names = (const char *[]){ - "mmss_spdm_csi0_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_gfx3d_clk = { - .halt_reg = 0x022c, - .clkr = { - .enable_reg = 0x022c, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_gfx3d_clk", - .parent_names = (const char *[]){ - "mmss_spdm_gfx3d_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_jpeg0_clk = { - .halt_reg = 0x0204, - .clkr = { - .enable_reg = 0x0204, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_jpeg0_clk", - .parent_names = (const char *[]){ - "mmss_spdm_jpeg0_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_jpeg1_clk = { - .halt_reg = 0x0208, - .clkr = { - .enable_reg = 0x0208, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_jpeg1_clk", - .parent_names = (const char *[]){ - "mmss_spdm_jpeg1_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_jpeg2_clk = { - .halt_reg = 0x0224, - .clkr = { - .enable_reg = 0x0224, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_jpeg2_clk", - .parent_names = (const char *[]){ - "mmss_spdm_jpeg2_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_mdp_clk = { - .halt_reg = 0x020c, - .clkr = { - .enable_reg = 0x020c, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_mdp_clk", - .parent_names = (const char *[]){ - "mmss_spdm_mdp_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_pclk0_clk = { - .halt_reg = 0x0234, - .clkr = { - .enable_reg = 0x0234, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_pclk0_clk", - .parent_names = (const char *[]){ - "mmss_spdm_pclk0_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_pclk1_clk = { - .halt_reg = 0x0228, - .clkr = { - .enable_reg = 0x0228, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_pclk1_clk", - .parent_names = (const char *[]){ - "mmss_spdm_pclk1_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_vcodec0_clk = { - .halt_reg = 0x0214, - .clkr = { - .enable_reg = 0x0214, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_vcodec0_clk", - .parent_names = (const char *[]){ - "mmss_spdm_vcodec0_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_vfe0_clk = { - .halt_reg = 0x0218, - .clkr = { - .enable_reg = 0x0218, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_vfe0_clk", - .parent_names = (const char *[]){ - "mmss_spdm_vfe0_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_vfe1_clk = { - .halt_reg = 0x021c, - .clkr = { - .enable_reg = 0x021c, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_vfe1_clk", - .parent_names = (const char *[]){ - "mmss_spdm_vfe1_div_clk", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_rm_axi_clk = { - .halt_reg = 0x0304, - .clkr = { - .enable_reg = 0x0304, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_rm_axi_clk", - .parent_names = (const char *[]){ - "mmss_axi_clk_src", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - -static struct clk_branch mmss_spdm_rm_ocmemnoc_clk = { - .halt_reg = 0x0308, - .clkr = { - .enable_reg = 0x0308, - .enable_mask = BIT(0), - .hw.init = &(struct clk_init_data){ - .name = "mmss_spdm_rm_ocmemnoc_clk", - .parent_names = (const char *[]){ - "ocmemnoc_clk_src", - }, - .num_parents = 1, - .flags = CLK_SET_RATE_PARENT, - .ops = &clk_branch2_ops, - }, - }, -}; - - static struct clk_branch mmss_misc_ahb_clk = { .halt_reg = 0x502c, .clkr = { @@ -3252,21 +2996,6 @@ static struct clk_regmap *mmcc_apq8084_clocks[] = { [MDSS_VSYNC_CLK] = &mdss_vsync_clk.clkr, [MMSS_RBCPR_AHB_CLK] = &mmss_rbcpr_ahb_clk.clkr, [MMSS_RBCPR_CLK] = &mmss_rbcpr_clk.clkr, - [MMSS_SPDM_AHB_CLK] = &mmss_spdm_ahb_clk.clkr, - [MMSS_SPDM_AXI_CLK] = &mmss_spdm_axi_clk.clkr, - [MMSS_SPDM_CSI0_CLK] = &mmss_spdm_csi0_clk.clkr, - [MMSS_SPDM_GFX3D_CLK] = &mmss_spdm_gfx3d_clk.clkr, - [MMSS_SPDM_JPEG0_CLK] = &mmss_spdm_jpeg0_clk.clkr, - [MMSS_SPDM_JPEG1_CLK] = &mmss_spdm_jpeg1_clk.clkr, - [MMSS_SPDM_JPEG2_CLK] = &mmss_spdm_jpeg2_clk.clkr, - [MMSS_SPDM_MDP_CLK] = &mmss_spdm_mdp_clk.clkr, - [MMSS_SPDM_PCLK0_CLK] = &mmss_spdm_pclk0_clk.clkr, - [MMSS_SPDM_PCLK1_CLK] = &mmss_spdm_pclk1_clk.clkr, - [MMSS_SPDM_VCODEC0_CLK] = &mmss_spdm_vcodec0_clk.clkr, - [MMSS_SPDM_VFE0_CLK] = &mmss_spdm_vfe0_clk.clkr, - [MMSS_SPDM_VFE1_CLK] = &mmss_spdm_vfe1_clk.clkr, - [MMSS_SPDM_RM_AXI_CLK] = &mmss_spdm_rm_axi_clk.clkr, - [MMSS_SPDM_RM_OCMEMNOC_CLK] = &mmss_spdm_rm_ocmemnoc_clk.clkr, [MMSS_MISC_AHB_CLK] = &mmss_misc_ahb_clk.clkr, [MMSS_MMSSNOC_AHB_CLK] = &mmss_mmssnoc_ahb_clk.clkr, [MMSS_MMSSNOC_BTO_AHB_CLK] = &mmss_mmssnoc_bto_ahb_clk.clkr, -- 2.39.2

1 year, 10 months

3
19
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[PATCH 5.10 0/1] usb: musb: core: drop redundant checks

by Danila Chernetsov

hw_ep can't be NULL but compared to NULL in 5.10 stable releases. The problem has been fixed by the following patch which can be cleanly applied to the 5.10 branch. Found by Linux Verification Center (linuxtesting.org) with SVACE.

1 year, 10 months

3
3
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[PATCH] wifi: mac80211: Serialize calls to drv_wake_tx_queue()

by Alexander Wetzel

drv_wake_tx_queue() has no protection against running concurrent multiple times. It's normally executed within the task calling ndo_start_xmit(). But wake_txqs_tasklet is also calling into it, regardless if the function is already running on another CPU or not. While drivers with native iTXQ support are able to handle that, calls to ieee80211_handle_wake_tx_queue() - used by the drivers without native iTXQ support - must be serialized. Otherwise drivers can get unexpected overlapping drv_tx() calls from mac80211. Which causes issues for at least rt2800usb. To avoid what seems to be a not needed distinction between native and drivers using ieee80211_handle_wake_tx_queue(), the serialization is done for drv_wake_tx_queue() here. The serialization works by detecting and blocking concurrent calls into drv_wake_tx_queue() and - when needed - restarting all queues after the wake_tx_queue ops returned from the driver. This fix here is only required when a tree has 'c850e31f79f0 ("wifi: mac80211: add internal handler for wake_tx_queue")', which introduced the buggy code path in mac80211. Drivers were switched to it with 'a790cc3a4fad ("wifi: mac80211: add wake_tx_queue callback to drivers")'. But only after fixing an independent bug with commit '4444bc2116ae ("wifi: mac80211: Proper mark iTXQs for resumption")' problematic concurrent calls to drv_wake_tx_queue() really happened and exposed the initial issue. Fixes: c850e31f79f0 ("wifi: mac80211: add internal handler for wake_tx_queue") Reported-by: Thomas Mann <rauchwolke(a)gmx.net> Tested-by: Thomas Mann <rauchwolke(a)gmx.net> Link: https://bugzilla.kernel.org/show_bug.cgi?id=217119 Link: https://lore.kernel.org/r/b8efebc6-4399-d0b8-b2a0-66843314616b@leemhuis.inf… CC: <stable(a)vger.kernel.org> Signed-off-by: Alexander Wetzel <alexander(a)wetzel-home.de> --- There are multiple variations how we can fix the issue. But this fix has to go directly into 6.2 to solve an ongoing regression. I tried to prevent an outright redesign while still having a full fix: Most questionable decision here probably is, if we should fix it in drv_wake_tx_queue() or only in ieee80211_handle_wake_tx_queue(). But the decision how to serialize - tasklet vs some kind of locking - may also be an issue. Personally, I did not like the overhead of checking all iTXQ for every drv_wake_tx_queue(). These are happening per-packet AND can be easily avoided when we are not using a tasklet. Most of the time. I also assume that drivers don't *want* concurrent drv_wake_tx_queue() calls and it's a benefit to all drivers to serialize it. If we consider concurrent calls for drv_wake_tx_queue() to be a feature, I would just move the code into ieee80211_handle_wake_tx_queue(). Which may also be the solution for the regression in 6.2: Do it now for ieee80211_handle_wake_tx_queue() and apply this patch to the development tree only. We could probably also do it without the queue stops. But then __ieee80211_wake_queue() needs more modifications. Thus I ended up with the approach in this patch... Alexander --- net/mac80211/driver-ops.h | 21 +++++++++++++++++++++ net/mac80211/ieee80211_i.h | 9 +++++++++ net/mac80211/util.c | 3 ++- 3 files changed, 32 insertions(+), 1 deletion(-) diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h index 5d13a3dfd366..8bc4904c32e2 100644 --- a/net/mac80211/driver-ops.h +++ b/net/mac80211/driver-ops.h @@ -1192,6 +1192,16 @@ drv_tdls_recv_channel_switch(struct ieee80211_local *local, trace_drv_return_void(local); } +static void handle_aborted_drv_wake_tx_queue(struct ieee80211_hw *hw) +{ + ieee80211_stop_queues_by_reason(hw, IEEE80211_MAX_QUEUE_MAP, + IEEE80211_QUEUE_STOP_REASON_SERIALIZE, + false); + ieee80211_wake_queues_by_reason(hw, IEEE80211_MAX_QUEUE_MAP, + IEEE80211_QUEUE_STOP_REASON_SERIALIZE, + false); +} + static inline void drv_wake_tx_queue(struct ieee80211_local *local, struct txq_info *txq) { @@ -1206,8 +1216,19 @@ static inline void drv_wake_tx_queue(struct ieee80211_local *local, if (!check_sdata_in_driver(sdata)) return; + /* Serialize calls to wake_tx_queue */ + if (test_and_set_bit(ITXQ_RUN_WAKE_TX_QUEUE_ACTIVE, + &local->itxq_run_flags)) { + set_bit(ITXQ_RUN_WAKE_TX_QUEUE_NEEDED, &local->itxq_run_flags); + return; + } trace_drv_wake_tx_queue(local, sdata, txq); local->ops->wake_tx_queue(&local->hw, &txq->txq); + clear_bit(ITXQ_RUN_WAKE_TX_QUEUE_ACTIVE, &local->itxq_run_flags); + + if (test_and_clear_bit(ITXQ_RUN_WAKE_TX_QUEUE_NEEDED, + &local->itxq_run_flags)) + handle_aborted_drv_wake_tx_queue(&local->hw); } static inline void schedule_and_wake_txq(struct ieee80211_local *local, diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index ecc232eb1ee8..42cd32892186 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1197,6 +1197,7 @@ enum queue_stop_reason { IEEE80211_QUEUE_STOP_REASON_TDLS_TEARDOWN, IEEE80211_QUEUE_STOP_REASON_RESERVE_TID, IEEE80211_QUEUE_STOP_REASON_IFTYPE_CHANGE, + IEEE80211_QUEUE_STOP_REASON_SERIALIZE, IEEE80211_QUEUE_STOP_REASONS, }; @@ -1269,6 +1270,11 @@ enum mac80211_scan_state { DECLARE_STATIC_KEY_FALSE(aql_disable); +enum itxq_run_flags { + ITXQ_RUN_WAKE_TX_QUEUE_ACTIVE, + ITXQ_RUN_WAKE_TX_QUEUE_NEEDED, +}; + struct ieee80211_local { /* embed the driver visible part. * don't cast (use the static inlines below), but we keep @@ -1284,6 +1290,9 @@ struct ieee80211_local { struct list_head active_txqs[IEEE80211_NUM_ACS]; u16 schedule_round[IEEE80211_NUM_ACS]; + /* Used to handle/prevent overlapping calls to drv_wake_tx_queue() */ + unsigned long itxq_run_flags; + u16 airtime_flags; u32 aql_txq_limit_low[IEEE80211_NUM_ACS]; u32 aql_txq_limit_high[IEEE80211_NUM_ACS]; diff --git a/net/mac80211/util.c b/net/mac80211/util.c index 1a28fe5cb614..48483eed4826 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -474,7 +474,8 @@ static void __ieee80211_wake_queue(struct ieee80211_hw *hw, int queue, * release someone's lock, but it is fine because all the callers of * __ieee80211_wake_queue call it right before releasing the lock. */ - if (reason == IEEE80211_QUEUE_STOP_REASON_DRIVER) + if (reason == IEEE80211_QUEUE_STOP_REASON_DRIVER || + reason == IEEE80211_QUEUE_STOP_REASON_SERIALIZE) tasklet_schedule(&local->wake_txqs_tasklet); else _ieee80211_wake_txqs(local, flags); -- 2.39.2

1 year, 10 months

3
9
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[PATCH v3] i2c: xgene-slimpro: Fix out-of-bounds bug in xgene_slimpro_i2c_xfer()

by Wei Chen

The data->block[0] variable comes from user and is a number between 0-255. Without proper check, the variable may be very large to cause an out-of-bounds when performing memcpy in slimpro_i2c_blkwr. Fix this bug by checking the value of writelen. Fixes: f6505fbabc42 ("i2c: add SLIMpro I2C device driver on APM X-Gene platform") Signed-off-by: Wei Chen <harperchen1110(a)gmail.com> --- Changes in v2: - Put length check inside slimpro_i2c_blkwr Changes in v3: - Correct the format of patch drivers/i2c/busses/i2c-xgene-slimpro.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/i2c/busses/i2c-xgene-slimpro.c b/drivers/i2c/busses/i2c-xgene-slimpro.c index bc9a3e7e0c96..0f7263e2276a 100644 --- a/drivers/i2c/busses/i2c-xgene-slimpro.c +++ b/drivers/i2c/busses/i2c-xgene-slimpro.c @@ -308,6 +308,9 @@ static int slimpro_i2c_blkwr(struct slimpro_i2c_dev *ctx, u32 chip, u32 msg[3]; int rc; + if (writelen > I2C_SMBUS_BLOCK_MAX) + return -EINVAL; + memcpy(ctx->dma_buffer, data, writelen); paddr = dma_map_single(ctx->dev, ctx->dma_buffer, writelen, DMA_TO_DEVICE); -- 2.25.1

1 year, 10 months

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[PATCH v2 8/9] PCI: rockchip: Use u32 variable to access 32-bit registers

by Rick Wertenbroek

Previously u16 variables were used to access 32-bit registers, this resulted in not all of the data being read from the registers. Also the left shift of more than 16-bits would result in moving data out of the variable. Use u32 variables to access 32-bit registers Fixes: cf590b078391 ("PCI: rockchip: Add EP driver for Rockchip PCIe controller") Cc: stable(a)vger.kernel.org Signed-off-by: Rick Wertenbroek <rick.wertenbroek(a)gmail.com> --- drivers/pci/controller/pcie-rockchip-ep.c | 10 +++++----- drivers/pci/controller/pcie-rockchip.h | 1 + 2 files changed, 6 insertions(+), 5 deletions(-) diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c index ca5b363ba..b7865a94e 100644 --- a/drivers/pci/controller/pcie-rockchip-ep.c +++ b/drivers/pci/controller/pcie-rockchip-ep.c @@ -292,15 +292,15 @@ static int rockchip_pcie_ep_set_msi(struct pci_epc *epc, u8 fn, u8 vfn, { struct rockchip_pcie_ep *ep = epc_get_drvdata(epc); struct rockchip_pcie *rockchip = &ep->rockchip; - u16 flags; + u32 flags; flags = rockchip_pcie_read(rockchip, ROCKCHIP_PCIE_EP_FUNC_BASE(fn) + ROCKCHIP_PCIE_EP_MSI_CTRL_REG); flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK; flags |= - ((multi_msg_cap << 1) << ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) | - PCI_MSI_FLAGS_64BIT; + (multi_msg_cap << ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET) | + (PCI_MSI_FLAGS_64BIT << ROCKCHIP_PCIE_EP_MSI_FLAGS_OFFSET); flags &= ~ROCKCHIP_PCIE_EP_MSI_CTRL_MASK_MSI_CAP; rockchip_pcie_write(rockchip, flags, ROCKCHIP_PCIE_EP_FUNC_BASE(fn) + @@ -312,7 +312,7 @@ static int rockchip_pcie_ep_get_msi(struct pci_epc *epc, u8 fn, u8 vfn) { struct rockchip_pcie_ep *ep = epc_get_drvdata(epc); struct rockchip_pcie *rockchip = &ep->rockchip; - u16 flags; + u32 flags; flags = rockchip_pcie_read(rockchip, ROCKCHIP_PCIE_EP_FUNC_BASE(fn) + @@ -374,7 +374,7 @@ static int rockchip_pcie_ep_send_msi_irq(struct rockchip_pcie_ep *ep, u8 fn, u8 interrupt_num) { struct rockchip_pcie *rockchip = &ep->rockchip; - u16 flags, mme, data, data_mask; + u32 flags, mme, data, data_mask; u8 msi_count; u64 pci_addr, pci_addr_mask = 0xff; u32 r; diff --git a/drivers/pci/controller/pcie-rockchip.h b/drivers/pci/controller/pcie-rockchip.h index e90c2a2b8..11dbf53cd 100644 --- a/drivers/pci/controller/pcie-rockchip.h +++ b/drivers/pci/controller/pcie-rockchip.h @@ -227,6 +227,7 @@ #define ROCKCHIP_PCIE_EP_CMD_STATUS 0x4 #define ROCKCHIP_PCIE_EP_CMD_STATUS_IS BIT(19) #define ROCKCHIP_PCIE_EP_MSI_CTRL_REG 0x90 +#define ROCKCHIP_PCIE_EP_MSI_FLAGS_OFFSET 16 #define ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_OFFSET 17 #define ROCKCHIP_PCIE_EP_MSI_CTRL_MMC_MASK GENMASK(19, 17) #define ROCKCHIP_PCIE_EP_MSI_CTRL_MME_OFFSET 20 -- 2.25.1

1 year, 10 months

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[tip: ras/urgent] x86/mce: Make sure logged MCEs are processed after sysfs update

by tip-bot2 for Yazen Ghannam

The following commit has been merged into the ras/urgent branch of tip: Commit-ID: 4783b9cb374af02d49740e00e2da19fd4ed6dec4 Gitweb: https://git.kernel.org/tip/4783b9cb374af02d49740e00e2da19fd4ed6dec4 Author: Yazen Ghannam <yazen.ghannam(a)amd.com> AuthorDate: Wed, 01 Mar 2023 22:14:20 Committer: Borislav Petkov (AMD) <bp(a)alien8.de> CommitterDate: Sun, 12 Mar 2023 21:12:21 +01:00 x86/mce: Make sure logged MCEs are processed after sysfs update A recent change introduced a flag to queue up errors found during boot-time polling. These errors will be processed during late init once the MCE subsystem is fully set up. A number of sysfs updates call mce_restart() which goes through a subset of the CPU init flow. This includes polling MCA banks and logging any errors found. Since the same function is used as boot-time polling, errors will be queued. However, the system is now past late init, so the errors will remain queued until another error is found and the workqueue is triggered. Call mce_schedule_work() at the end of mce_restart() so that queued errors are processed. Fixes: 3bff147b187d ("x86/mce: Defer processing of early errors") Signed-off-by: Yazen Ghannam <yazen.ghannam(a)amd.com> Signed-off-by: Borislav Petkov (AMD) <bp(a)alien8.de> Reviewed-by: Tony Luck <tony.luck(a)intel.com> Cc: stable(a)vger.kernel.org Link: https://lore.kernel.org/r/20230301221420.2203184-1-yazen.ghannam@amd.com --- arch/x86/kernel/cpu/mce/core.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 7832a69..2eec60f 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -2355,6 +2355,7 @@ static void mce_restart(void) { mce_timer_delete_all(); on_each_cpu(mce_cpu_restart, NULL, 1); + mce_schedule_work(); } /* Toggle features for corrected errors */

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Linux-stable-mirror March 2023