0db6f8d782
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>
108 lines
3.3 KiB
C
108 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* code tagging framework
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*/
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#ifndef _LINUX_CODETAG_H
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#define _LINUX_CODETAG_H
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#include <linux/types.h>
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struct codetag_iterator;
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struct codetag_type;
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struct codetag_module;
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struct seq_buf;
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struct module;
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/*
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* An instance of this structure is created in a special ELF section at every
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* code location being tagged. At runtime, the special section is treated as
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* an array of these.
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*/
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struct codetag {
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unsigned int flags; /* used in later patches */
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unsigned int lineno;
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const char *modname;
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const char *function;
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const char *filename;
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} __aligned(8);
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union codetag_ref {
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struct codetag *ct;
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};
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struct codetag_type_desc {
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const char *section;
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size_t tag_size;
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void (*module_load)(struct codetag_type *cttype,
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struct codetag_module *cmod);
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void (*module_unload)(struct codetag_type *cttype,
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struct codetag_module *cmod);
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#ifdef CONFIG_MODULES
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void (*module_replaced)(struct module *mod, struct module *new_mod);
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bool (*needs_section_mem)(struct module *mod, unsigned long size);
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void *(*alloc_section_mem)(struct module *mod, unsigned long size,
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unsigned int prepend, unsigned long align);
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void (*free_section_mem)(struct module *mod, bool used);
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#endif
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};
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struct codetag_iterator {
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struct codetag_type *cttype;
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struct codetag_module *cmod;
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unsigned long mod_id;
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struct codetag *ct;
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};
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#ifdef MODULE
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#define CT_MODULE_NAME KBUILD_MODNAME
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#else
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#define CT_MODULE_NAME NULL
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#endif
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#define CODE_TAG_INIT { \
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.modname = CT_MODULE_NAME, \
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.function = __func__, \
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.filename = __FILE__, \
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.lineno = __LINE__, \
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.flags = 0, \
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}
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void codetag_lock_module_list(struct codetag_type *cttype, bool lock);
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bool codetag_trylock_module_list(struct codetag_type *cttype);
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struct codetag_iterator codetag_get_ct_iter(struct codetag_type *cttype);
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struct codetag *codetag_next_ct(struct codetag_iterator *iter);
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void codetag_to_text(struct seq_buf *out, struct codetag *ct);
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struct codetag_type *
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codetag_register_type(const struct codetag_type_desc *desc);
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#if defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES)
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bool codetag_needs_module_section(struct module *mod, const char *name,
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unsigned long size);
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void *codetag_alloc_module_section(struct module *mod, const char *name,
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unsigned long size, unsigned int prepend,
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unsigned long align);
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void codetag_free_module_sections(struct module *mod);
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void codetag_module_replaced(struct module *mod, struct module *new_mod);
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void codetag_load_module(struct module *mod);
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void codetag_unload_module(struct module *mod);
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#else /* defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES) */
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static inline bool
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codetag_needs_module_section(struct module *mod, const char *name,
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unsigned long size) { return false; }
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static inline void *
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codetag_alloc_module_section(struct module *mod, const char *name,
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unsigned long size, unsigned int prepend,
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unsigned long align) { return NULL; }
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static inline void codetag_free_module_sections(struct module *mod) {}
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static inline void codetag_module_replaced(struct module *mod, struct module *new_mod) {}
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static inline void codetag_load_module(struct module *mod) {}
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static inline void codetag_unload_module(struct module *mod) {}
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#endif /* defined(CONFIG_CODE_TAGGING) && defined(CONFIG_MODULES) */
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#endif /* _LINUX_CODETAG_H */
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