Messages in this thread | | | Subject | Re: [PATCH] mm: cma: fix corruption cma_sysfs_alloc_pages_count | From | David Hildenbrand <> | Date | Wed, 24 Mar 2021 20:53:26 +0100 |
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On 24.03.21 20:45, John Hubbard wrote: > On 3/24/21 12:20 PM, Minchan Kim wrote: >> struct cma_stat's lifespan for cma_sysfs is different with >> struct cma because kobject for sysfs requires dynamic object >> while CMA is static object[1]. When CMA is initialized, >> it couldn't use slab to allocate cma_stat since slab was not >> initialized yet. Thus, it allocates the dynamic object >> in subsys_initcall. >> >> However, the cma allocation can happens before subsys_initcall >> then, it goes crash. >> >> Dmitry reported[2]: >> >> .. >> [ 1.226190] [<c027762f>] (cma_sysfs_alloc_pages_count) from [<c027706f>] (cma_alloc+0x153/0x274) >> [ 1.226720] [<c027706f>] (cma_alloc) from [<c01112ab>] (__alloc_from_contiguous+0x37/0x8c) >> [ 1.227272] [<c01112ab>] (__alloc_from_contiguous) from [<c1104af9>] (atomic_pool_init+0x7b/0x126) >> [ 1.233596] [<c1104af9>] (atomic_pool_init) from [<c0101d69>] (do_one_initcall+0x45/0x1e4) >> [ 1.234188] [<c0101d69>] (do_one_initcall) from [<c1101141>] (kernel_init_freeable+0x157/0x1a6) >> [ 1.234741] [<c1101141>] (kernel_init_freeable) from [<c0a27fd1>] (kernel_init+0xd/0xe0) >> [ 1.235289] [<c0a27fd1>] (kernel_init) from [<c0100155>] (ret_from_fork+0x11/0x1c) >> >> This patch moves those statistic fields of cma_stat into struct cma >> and introduces cma_kobject wrapper to follow kobject's rule. >> >> At the same time, it fixes other routines based on suggestions[3][4]. >> >> [1] https://lore.kernel.org/linux-mm/YCOAmXqt6dZkCQYs@kroah.com/ >> [2] https://lore.kernel.org/linux-mm/fead70a2-4330-79ff-e79a-d8511eab1256@gmail.com/ >> [3] https://lore.kernel.org/linux-mm/20210323195050.2577017-1-minchan@kernel.org/ >> [4] https://lore.kernel.org/linux-mm/20210324010547.4134370-1-minchan@kernel.org/ >> >> Reported-by: Dmitry Osipenko <digetx@gmail.com> >> Tested-by: Dmitry Osipenko <digetx@gmail.com> >> Suggested-by: Dmitry Osipenko <digetx@gmail.com> >> Suggested-by: John Hubbard <jhubbard@nvidia.com> >> Suggested-by: Matthew Wilcox <willy@infradead.org> >> Signed-off-by: Minchan Kim <minchan@kernel.org> >> --- >> I belive it's worth to have separate patch rather than replacing >> original patch. It will also help to merge without conflict >> since we already filed other patch based on it. >> Strictly speaking, separating fix part and readbility part >> in this patch would be better but it's gray to separate them >> since most code in this patch was done while we were fixing >> the bug. Since we don't release it yet, I hope it will work. >> Otherwise, I can send a replacement patch inclucing all of >> changes happend until now with gathering SoB. > > If we still have a choice, we should not merge a patch that has a known > serious problem, such as a crash. That's only done if the broken problematic > patch has already been committed to a tree that doesn't allow rebasing, > such as of course the main linux.git. > > Here, I *think* it's just in linux-next and mmotm, so we still are allowed > to fix the original patch.
Yes, that's what we should do in case it's not upstream yet. Clean resend + re-apply.
-- Thanks,
David / dhildenb
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