kernel/linux.git/include/linux/poison.h, branch v6.1.168

fs: Use CHECK_DATA_CORRUPTION() when kernel bugs are detected

2023-03-10T08:33:46+00:00

[ Upstream commit 47d586913f2abec4d240bae33417f537fda987ec ] Currently, filp_close() and generic_shutdown_super() use printk() to log messages when bugs are detected. This is problematic because infrastructure like syzkaller has no idea that this message indicates a bug. In addition, some people explicitly want their kernels to BUG() when kernel data corruption has been detected (CONFIG_BUG_ON_DATA_CORRUPTION). And finally, when generic_shutdown_super() detects remaining inodes on a system without CONFIG_BUG_ON_DATA_CORRUPTION, it would be nice if later accesses to a busy inode would at least crash somewhat cleanly rather than walking through freed memory. To address all three, use CHECK_DATA_CORRUPTION() when kernel bugs are detected. Signed-off-by: Jann Horn Reviewed-by: Christian Brauner (Microsoft) Reviewed-by: Kees Cook Signed-off-by: Christian Brauner (Microsoft) Signed-off-by: Sasha Levin

bpf: Add verifier check for BPF_PTR_POISON retval and arg

2022-09-15T09:44:07+00:00

BPF_PTR_POISON was added in commit c0a5a21c25f37 ("bpf: Allow storing referenced kptr in map") to denote a bpf_func_proto btf_id which the verifier will replace with a dynamically-determined btf_id at verification time. This patch adds verifier 'poison' functionality to BPF_PTR_POISON in order to prepare for expanded use of the value to poison ret- and arg-btf_id in ongoing work, namely rbtree and linked list patchsets [0, 1]. Specifically, when the verifier checks helper calls, it assumes that BPF_PTR_POISON'ed ret type will be replaced with a valid type before - or in lieu of - the default ret_btf_id logic. Similarly for arg btf_id. If poisoned btf_id reaches default handling block for either, consider this a verifier internal error and fail verification. Otherwise a helper w/ poisoned btf_id but no verifier logic replacing the type will cause a crash as the invalid pointer is dereferenced. Also move BPF_PTR_POISON to existing include/linux/posion.h header and remove unnecessary shift. [0]: lore.kernel.org/bpf/20220830172759.4069786-1-davemarchevsky@fb.com [1]: lore.kernel.org/bpf/20220904204145.3089-1-memxor@gmail.com Signed-off-by: Dave Marchevsky Acked-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20220912154544.1398199-1-davemarchevsky@fb.com Signed-off-by: Alexei Starovoitov

mm: add a signature in struct page

2021-06-07T21:11:47+00:00

This is needed by the page_pool to avoid recycling a page not allocated via page_pool. The page->signature field is aliased to page->lru.next and page->compound_head, but it can't be set by mistake because the signature value is a bad pointer, and can't trigger a false positive in PageTail() because the last bit is 0. Co-developed-by: Matthew Wilcox (Oracle) Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Matteo Croce Signed-off-by: David S. Miller

mm, page_poison: remove CONFIG_PAGE_POISONING_ZERO

2020-12-15T20:13:46+00:00

CONFIG_PAGE_POISONING_ZERO uses the zero pattern instead of 0xAA. It was introduced by commit 1414c7f4f7d7 ("mm/page_poisoning.c: allow for zero poisoning"), noting that using zeroes retains the benefit of sanitizing content of freed pages, with the benefit of not having to zero them again on alloc, and the downside of making some forms of corruption (stray writes of NULLs) harder to detect than with the 0xAA pattern. Together with CONFIG_PAGE_POISONING_NO_SANITY it made possible to sanitize the contents on free without checking it back on alloc. These days we have the init_on_free() option to achieve sanitization with zeroes and to save clearing on alloc (and without checking on alloc). Arguably if someone does choose to check the poison for corruption on alloc, the savings of not clearing the page are secondary, and it makes sense to always use the 0xAA poison pattern. Thus, remove the CONFIG_PAGE_POISONING_ZERO option for being redundant. Link: https://lkml.kernel.org/r/20201113104033.22907-6-vbabka@suse.cz Signed-off-by: Vlastimil Babka Acked-by: David Hildenbrand Cc: Mike Rapoport Cc: Rafael J. Wysocki Cc: Alexander Potapenko Cc: Kees Cook Cc: Laura Abbott Cc: Mateusz Nosek Cc: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

include/linux/poison.h: remove obsolete comment

2020-08-12T17:57:59+00:00

When the definition was changed, the comment became stale. Just remove it since there isn't anything useful to say here. Fixes: b8a0255db958 ("include/linux/poison.h: use POISON_POINTER_DELTA for poison pointers") Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Cc: Vasily Kulikov Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20200730174108.GJ23808@casper.infradead.org Signed-off-by: Linus Torvalds

lib/list: tweak LIST_POISON2 for better code generation on x86_64

2019-07-17T02:23:22+00:00

list_del() poisoning can generate 2 64-bit immediate loads but it also can generate one 64-bit immediate load and an addition: 48 b8 00 01 00 00 00 00 ad de movabs rax,0xdead000000000100 48 89 47 58 mov QWORD PTR [rdi+0x58],rax 48 05 00 01 00 00 <=====> add rax,0x100 48 89 47 60 mov QWORD PTR [rdi+0x60],rax However on x86_64 not all constants are equal: those within [-128, 127] range can be added with shorter "add r64, imm32" instruction: 48 b8 00 01 00 00 00 00 ad de movabs rax,0xdead000000000100 48 89 47 58 mov QWORD PTR [rdi+0x58],rax 48 83 c0 22 <======> add rax,0x22 48 89 47 60 mov QWORD PTR [rdi+0x60],rax Patch saves 2 bytes per some LIST_POISON2 usage. (Slightly disappointing) space savings on F29 x86_64 config: add/remove: 0/0 grow/shrink: 0/2164 up/down: 0/-5184 (-5184) Function old new delta zstd_get_workspace 548 546 -2 ... mlx4_delete_all_resources_for_slave 4826 4804 -22 Total: Before=83304131, After=83298947, chg -0.01% New constants are: 0xdead000000000100 0xdead000000000122 Note: LIST_POISON1 can't be changed to ...11 because something in page allocator requires low bit unset. Link: http://lkml.kernel.org/r/20190513191502.GA8492@avx2 Signed-off-by: Alexey Dobriyan Cc: Vasiliy Kulikov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Drop flex_arrays

2019-03-12T17:04:03+00:00

All existing users have been converted to generic radix trees Link: http://lkml.kernel.org/r/20181217131929.11727-8-kent.overstreet@gmail.com Signed-off-by: Kent Overstreet Acked-by: Dave Hansen Cc: Alexey Dobriyan Cc: Al Viro Cc: Eric Paris Cc: Marcelo Ricardo Leitner Cc: Matthew Wilcox Cc: Neil Horman Cc: Paul Moore Cc: Pravin B Shelar Cc: Shaohua Li Cc: Stephen Smalley Cc: Vlad Yasevich Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/page_poison: update comment after code moved

2019-03-06T05:07:20+00:00

mm/debug-pagealloc.c is no more, so of course header now needs to be updated. This seems like something checkpatch should be able to catch - worth looking into? Link: http://lkml.kernel.org/r/20190207191113.14039-1-mst@redhat.com Fixes: 8823b1dbc05f ("mm/page_poison.c: enable PAGE_POISONING as a separate option") Signed-off-by: Michael S. Tsirkin Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55+00:00

Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

locking/mutex: Initialize mutex_waiter::ww_ctx with poison when debugging

2017-01-14T10:14:53+00:00

Help catch cases where mutex_lock is used directly on w/w mutexes, which otherwise result in the w/w tasks reading uninitialized data. Signed-off-by: Nicolai Hähnle Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Chris Wilson Cc: Daniel Vetter Cc: Linus Torvalds Cc: Maarten Lankhorst Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: dri-devel@lists.freedesktop.org Link: http://lkml.kernel.org/r/1482346000-9927-12-git-send-email-nhaehnle@gmail.com Signed-off-by: Ingo Molnar