pm24.git/lib, branch rust-fixes-6.3

Merge tag 'xfs-6.3-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

2023-03-25T19:57:34Z

Pull xfs percpu counter fixes from Darrick Wong: "We discovered a filesystem summary counter corruption problem that was traced to cpu hot-remove racing with the call to percpu_counter_sum that sets the free block count in the superblock when writing it to disk. The root cause is that percpu_counter_sum doesn't cull from dying cpus and hence misses those counter values if the cpu shutdown hooks have not yet run to merge the values. I'm hoping this is a fairly painless fix to the problem, since the dying cpu mask should generally be empty. It's been in for-next for a week without any complaints from the bots. - Fix a race in the percpu counters summation code where the summation failed to add in the values for any CPUs that were dying but not yet dead. This fixes some minor discrepancies and incorrect assertions when running generic/650" * tag 'xfs-6.3-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: pcpcntr: remove percpu_counter_sum_all() fork: remove use of percpu_counter_sum_all pcpcntrs: fix dying cpu summation race cpumask: introduce for_each_cpu_or

lib: dhry: fix unstable smp_processor_id(_) usage

2023-03-24T00:18:35Z

When running the in-kernel Dhrystone benchmark with CONFIG_DEBUG_PREEMPT=y: BUG: using smp_processor_id() in preemptible [00000000] code: bash/938 Fix this by not using smp_processor_id() directly, but instead wrapping the whole benchmark inside a get_cpu()/put_cpu() pair. This makes sure the whole benchmark is run on the same CPU core, and the reported values are consistent. Link: https://lkml.kernel.org/r/b0d29932bb24ad82cea7f821e295c898e9657be0.1678890070.git.geert+renesas@glider.be Fixes: d5528cc16893f1f6 ("lib: add Dhrystone benchmark test") Signed-off-by: Geert Uytterhoeven Reported-by: Tobias Klausmann Link: https://bugzilla.kernel.org/show_bug.cgi?id=217179 Signed-off-by: Andrew Morton

test_maple_tree: add more testing for mas_empty_area()

2023-03-24T00:18:32Z

Test robust filling of an entire area of the tree, then test one beyond. This is to test the walking back up the tree at the end of nodes and error condition. Test inspired by the reproducer code provided by Snild Dolkow. The last test in the function tests for the case of a corrupted maple state caused by the incorrect limits set during mas_skip_node(). There needs to be a gap in the second last child and last child, but the search must rule out the second last child's gap. This would avoid correcting the maple state to the correct max limit and return an error. Link: https://lkml.kernel.org/r/20230307180247.2220303-3-Liam.Howlett@oracle.com Cc: Snild Dolkow Link: https://lore.kernel.org/linux-mm/cb8dc31a-fef2-1d09-f133-e9f7b9f9e77a@sony.com/ Fixes: e15e06a83923 ("lib/test_maple_tree: add testing for maple tree") Signed-off-by: Liam R. Howlett Cc: Peng Zhang Cc: Signed-off-by: Andrew Morton

maple_tree: fix mas_skip_node() end slot detection

2023-03-24T00:18:32Z

Patch series "Fix mas_skip_node() for mas_empty_area()", v2. mas_empty_area() was incorrectly returning an error when there was room. The issue was tracked down to mas_skip_node() using the incorrect end-of-slot count. Instead of using the nodes hard limit, the limit of data should be used. mas_skip_node() was also setting the min and max to that of the child node, which was unnecessary. Within these limits being set, there was also a bug that corrupted the maple state's max if the offset was set to the maximum node pivot. The bug was without consequence unless there was a sufficient gap in the next child node which would cause an error to be returned. This patch set fixes these errors by removing the limit setting from mas_skip_node() and uses the mas_data_end() for slot limits, and adds tests for all failures discovered. This patch (of 2): mas_skip_node() is used to move the maple state to the node with a higher limit. It does this by walking up the tree and increasing the slot count. Since slot count may not be able to be increased, it may need to walk up multiple times to find room to walk right to a higher limit node. The limit of slots that was being used was the node limit and not the last location of data in the node. This would cause the maple state to be shifted outside actual data and enter an error state, thus returning -EBUSY. The result of the incorrect error state means that mas_awalk() would return an error instead of finding the allocation space. The fix is to use mas_data_end() in mas_skip_node() to detect the nodes data end point and continue walking the tree up until it is safe to move to a node with a higher limit. The walk up the tree also sets the maple state limits so remove the buggy code from mas_skip_node(). Setting the limits had the unfortunate side effect of triggering another bug if the parent node was full and the there was no suitable gap in the second last child, but room in the next child. mas_skip_node() may also be passed a maple state in an error state from mas_anode_descend() when no allocations are available. Return on such an error state immediately. Link: https://lkml.kernel.org/r/20230307180247.2220303-1-Liam.Howlett@oracle.com Link: https://lkml.kernel.org/r/20230307180247.2220303-2-Liam.Howlett@oracle.com Fixes: 54a611b60590 ("Maple Tree: add new data structure") Signed-off-by: Liam R. Howlett Reported-by: Snild Dolkow Link: https://lore.kernel.org/linux-mm/cb8dc31a-fef2-1d09-f133-e9f7b9f9e77a@sony.com/ Tested-by: Snild Dolkow Cc: Peng Zhang Cc: Signed-off-by: Andrew Morton

pcpcntr: remove percpu_counter_sum_all()

2023-03-19T17:02:04Z

percpu_counter_sum_all() is now redundant as the race condition it was invented to handle is now dealt with by percpu_counter_sum() directly and all users of percpu_counter_sum_all() have been removed. Remove it. This effectively reverts the changes made in f689054aace2 ("percpu_counter: add percpu_counter_sum_all interface") except for the cpumask iteration that fixes percpu_counter_sum() made earlier in this series. Signed-off-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

pcpcntrs: fix dying cpu summation race

2023-03-19T17:02:04Z

In commit f689054aace2 ("percpu_counter: add percpu_counter_sum_all interface") a race condition between a cpu dying and percpu_counter_sum() iterating online CPUs was identified. The solution was to iterate all possible CPUs for summation via percpu_counter_sum_all(). We recently had a percpu_counter_sum() call in XFS trip over this same race condition and it fired a debug assert because the filesystem was unmounting and the counter *should* be zero just before we destroy it. That was reported here: https://lore.kernel.org/linux-kernel/20230314090649.326642-1-yebin@huaweicloud.com/ likely as a result of running generic/648 which exercises filesystems in the presence of CPU online/offline events. The solution to use percpu_counter_sum_all() is an awful one. We use percpu counters and percpu_counter_sum() for accurate and reliable threshold detection for space management, so a summation race condition during these operations can result in overcommit of available space and that may result in filesystem shutdowns. As percpu_counter_sum_all() iterates all possible CPUs rather than just those online or even those present, the mask can include CPUs that aren't even installed in the machine, or in the case of machines that can hot-plug CPU capable nodes, even have physical sockets present in the machine. Fundamentally, this race condition is caused by the CPU being offlined being removed from the cpu_online_mask before the notifier that cleans up per-cpu state is run. Hence percpu_counter_sum() will not sum the count for a cpu currently being taken offline, regardless of whether the notifier has run or not. This is the root cause of the bug. The percpu counter notifier iterates all the registered counters, locks the counter and moves the percpu count to the global sum. This is serialised against other operations that move the percpu counter to the global sum as well as percpu_counter_sum() operations that sum the percpu counts while holding the counter lock. Hence the notifier is safe to run concurrently with sum operations, and the only thing we actually need to care about is that percpu_counter_sum() iterates dying CPUs. That's trivial to do, and when there are no CPUs dying, it has no addition overhead except for a cpumask_or() operation. This change makes percpu_counter_sum() always do the right thing in the presence of CPU hot unplug events and makes percpu_counter_sum_all() unnecessary. This, in turn, means that filesystems like XFS, ext4, and btrfs don't have to work out when they should use percpu_counter_sum() vs percpu_counter_sum_all() in their space accounting algorithms Signed-off-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

cpumask: introduce for_each_cpu_or

2023-03-19T17:02:04Z

Equivalent of for_each_cpu_and, except it ORs the two masks together so it iterates all the CPUs present in either mask. Signed-off-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

Merge tag 'zstd-linus-v6.3-rc3' of https://github.com/terrelln/linux

2023-03-15T00:03:25Z

Pull zstd fixes from Nick Terrell: "A small number of fixes for zstd-v1.5.2. I'm not pulling in zstd-v1.5.4 from upstream this release because it didn't have any time to bake in linux-next, but I'm aiming for the next update in v6.4" * tag 'zstd-linus-v6.3-rc3' of https://github.com/terrelln/linux: zstd: Fix definition of assert() lib: zstd: Backport fix for in-place decompression lib: zstd: Fix -Wstringop-overflow warning

zstd: Fix definition of assert()

2023-03-06T23:54:54Z

assert(x) should emit a warning if x is false. WARN_ON(x) emits a warning if x is true. Thus, assert(x) should be defined as WARN_ON(!x) rather than WARN_ON(x). Signed-off-by: Jonathan Neuschäfer Signed-off-by: Nick Terrell

lib: zstd: Backport fix for in-place decompression

2023-03-06T23:51:44Z

Backport the relevant part of upstream commit 5b266196 [0]. This fixes in-place decompression for x86-64 kernel decompression. It uses a bound of 131072 + (uncompressed_size >> 8), which can be violated after upstream commit 6a7ede3d [1], as zstd can use part of the output buffer as temporary storage, and without this patch needs a bound of ~262144. The fix is for zstd to detect that the input and output buffers overlap, so that zstd knows it can't use the overlapping portion of the output buffer as tempoary storage. If the margin is not large enough, this will ensure that zstd will fail the decompression, rather than overwriting part of the input data, and causing corruption. This fix has been landed upstream and is in release v1.5.4. That commit also adds unit and fuzz tests to verify that the margin we use is respected, and correct. That means that the fix is well tested upstream. I have not been able to reproduce the potential bug in x86-64 kernel decompression locally, nor have I recieved reports of failures to decompress the kernel. It is possible that compression saves enough space to make it very hard for the issue to appear. I've boot tested the zstd compressed kernel on x86-64 and i386 with this patch, which uses in-place decompression, and sanity tested zstd compression in btrfs / squashfs to make sure that we don't see any issues, but other uses of zstd shouldn't be affected, because they don't use in-place decompression. Thanks to Vasily Gorbik for debugging a related issue on s390, which was triggered by the same commit, but was a bug in how __decompress() was called [2]. And to Sasha Levin for the CC alerting me of the issue. [0] https://github.com/facebook/zstd/commit/5b266196a41e6a15e21bd4f0eeab43b938db1d90 [1] https://github.com/facebook/zstd/commit/6a7ede3dfccbf3e0a5928b4224a039c260dcff72 [2] https://lore.kernel.org/r/patch-1.thread-41c676.git-41c676c2d153.your-ad-here.call-01675030179-ext-9637@work.hours CC: Vasily Gorbik CC: Heiko Carstens CC: Sasha Levin CC: Yann Collet Signed-off-by: Nick Terrell