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When a module gets unloaded there is a possibility that some of the allocations it made are still used and therefore the allocation tags corresponding to these allocations are still referenced. As such, the memory for these tags can't be freed. This is currently handled as an abnormal situation and module's data section is not being unloaded. To handle this situation without keeping module's data in memory, allow codetags with longer lifespan than the module to be loaded into their own separate memory. The in-use memory areas and gaps after module unloading in this separate memory are tracked using maple trees. Allocation tags arrange their separate memory so that it is virtually contiguous and that will allow simple allocation tag indexing later on in this patchset. The size of this virtually contiguous memory is set to store up to 100000 allocation tags. [surenb@google.com: fix empty codetag module section handling] Link: https://lkml.kernel.org/r/20241101000017.3856204-1-surenb@google.com [akpm@linux-foundation.org: update comment, per Dan] Link: https://lkml.kernel.org/r/20241023170759.999909-4-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Christoph Hellwig <hch@infradead.org> Cc: Daniel Gomez <da.gomez@samsung.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: David Rientjes <rientjes@google.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Minchan Kim <minchan@google.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Petr Pavlu <petr.pavlu@suse.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Sourav Panda <souravpanda@google.com> Cc: Steven Rostedt (Google) <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Huth <thuth@redhat.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Xiongwei Song <xiongwei.song@windriver.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
34 lines
946 B
C
34 lines
946 B
C
/* SPDX-License-Identifier: GPL-2.0-only */
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#ifndef __ASM_GENERIC_CODETAG_LDS_H
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#define __ASM_GENERIC_CODETAG_LDS_H
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#define SECTION_WITH_BOUNDARIES(_name) \
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. = ALIGN(8); \
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__start_##_name = .; \
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KEEP(*(_name)) \
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__stop_##_name = .;
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#define CODETAG_SECTIONS() \
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SECTION_WITH_BOUNDARIES(alloc_tags)
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/*
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* Module codetags which aren't used after module unload, therefore have the
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* same lifespan as the module and can be safely unloaded with the module.
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*/
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#define MOD_CODETAG_SECTIONS()
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#define MOD_SEPARATE_CODETAG_SECTION(_name) \
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.codetag.##_name : { \
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SECTION_WITH_BOUNDARIES(_name) \
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}
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/*
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* For codetags which might be used after module unload, therefore might stay
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* longer in memory. Each such codetag type has its own section so that we can
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* unload them individually once unused.
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*/
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#define MOD_SEPARATE_CODETAG_SECTIONS() \
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MOD_SEPARATE_CODETAG_SECTION(alloc_tags)
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#endif /* __ASM_GENERIC_CODETAG_LDS_H */
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