kernel/linux.git/include/linux/fault-inject.h, branch v6.12.80

fault-inject: improve build for CONFIG_FAULT_INJECTION=n

2024-09-02T03:43:33+00:00

The fault-inject.h users across the kernel need to add a lot of #ifdef CONFIG_FAULT_INJECTION to cater for shortcomings in the header. Make fault-inject.h self-contained for CONFIG_FAULT_INJECTION=n, and add stubs for DECLARE_FAULT_ATTR(), setup_fault_attr(), should_fail_ex(), and should_fail() to allow removal of conditional compilation. [akpm@linux-foundation.org: repair fallout from no longer including debugfs.h into fault-inject.h] [akpm@linux-foundation.org: fix drivers/misc/xilinx_tmr_inject.c] [akpm@linux-foundation.org: Add debugfs.h inclusion to more files, per Stephen] Link: https://lkml.kernel.org/r/20240813121237.2382534-1-jani.nikula@intel.com Fixes: 6ff1cb355e62 ("[PATCH] fault-injection capabilities infrastructure") Signed-off-by: Jani Nikula Cc: Akinobu Mita Cc: Abhinav Kumar Cc: Dmitry Baryshkov Cc: Himal Prasad Ghimiray Cc: Lucas De Marchi Cc: Rob Clark Cc: Rodrigo Vivi Cc: Thomas Hellström Cc: Stephen Rothwell Signed-off-by: Andrew Morton

mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC

2024-07-18T04:05:18+00:00

This mostly reverts commit af3b854492f3 ("mm/page_alloc.c: allow error injection"). The commit made should_fail_alloc_page() a noinline function that's always called from the page allocation hotpath, even if it's empty because CONFIG_FAIL_PAGE_ALLOC is not enabled, and there is no option to disable it and prevent the associated function call overhead. As with the preceding patch "mm, slab: put should_failslab back behind CONFIG_SHOULD_FAILSLAB" and for the same reasons, put the should_fail_alloc_page() back behind the config option. When enabled, the ALLOW_ERROR_INJECTION and BTF_ID records are preserved so it's not a complete revert. Link: https://lkml.kernel.org/r/20240711-b4-fault-injection-reverts-v1-2-9e2651945d68@suse.cz Signed-off-by: Vlastimil Babka Cc: Akinobu Mita Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Christoph Lameter Cc: Daniel Borkmann Cc: David Rientjes Cc: Eduard Zingerman Cc: Hao Luo Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Jiri Olsa Cc: John Fastabend Cc: KP Singh Cc: Martin KaFai Lau Cc: Mateusz Guzik Cc: Roman Gushchin Cc: Song Liu Cc: Stanislav Fomichev Cc: Yonghong Song Signed-off-by: Andrew Morton

mm, slab: put should_failslab() back behind CONFIG_SHOULD_FAILSLAB

2024-07-18T04:05:18+00:00

Patch series "revert unconditional slab and page allocator fault injection calls". These two patches largely revert commits that added function call overhead into slab and page allocation hotpaths and that cannot be currently disabled even though related CONFIG_ options do exist. A much more involved solution that can keep the callsites always existing but hidden behind a static key if unused, is possible [1] and can be pursued by anyone who believes it's necessary. Meanwhile the fact the should_failslab() error injection is already not functional on kernels built with current gcc without anyone noticing [2], and lukewarm response to [1] suggests the need is not there. I believe it will be more fair to have the state after this series as a baseline for possible further optimisation, instead of the unconditional overhead. For example a possible compromise for anyone who's fine with an empty function call overhead but not the full CONFIG_FAILSLAB / CONFIG_FAIL_PAGE_ALLOC overhead is to reuse patch 1 from [1] but insert a static key check only inside should_failslab() and should_fail_alloc_page() before performing the more expensive checks. [1] https://lore.kernel.org/all/20240620-fault-injection-statickeys-v2-0-e23947d3d84b@suse.cz/#t [2] https://github.com/bpftrace/bpftrace/issues/3258 This patch (of 2): This mostly reverts commit 4f6923fbb352 ("mm: make should_failslab always available for fault injection"). The commit made should_failslab() a noinline function that's always called from the slab allocation hotpath, even if it's empty because CONFIG_SHOULD_FAILSLAB is not enabled, and there is no option to disable that call. This is visible in profiles and the function call overhead can be noticeable especially with cpu mitigations. Meanwhile the bpftrace program example in the commit silently does not work without CONFIG_SHOULD_FAILSLAB anyway with a recent gcc, because the empty function gets a .constprop clone that is actually being called (uselessly) from the slab hotpath, while the error injection is hooked to the original function that's not being called at all [1]. Thus put the whole should_failslab() function back behind CONFIG_SHOULD_FAILSLAB. It's not a complete revert of 4f6923fbb352 - the int return type that returns -ENOMEM on failure is preserved, as well ALLOW_ERROR_INJECTION annotation. The BTF_ID() record that was meanwhile added is also guarded by CONFIG_SHOULD_FAILSLAB. [1] https://github.com/bpftrace/bpftrace/issues/3258 Link: https://lkml.kernel.org/r/20240711-b4-fault-injection-reverts-v1-0-9e2651945d68@suse.cz Link: https://lkml.kernel.org/r/20240711-b4-fault-injection-reverts-v1-1-9e2651945d68@suse.cz Signed-off-by: Vlastimil Babka Cc: Akinobu Mita Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Christoph Lameter Cc: Daniel Borkmann Cc: David Rientjes Cc: Eduard Zingerman Cc: Hao Luo Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Jiri Olsa Cc: John Fastabend Cc: KP Singh Cc: Martin KaFai Lau Cc: Mateusz Guzik Cc: Roman Gushchin Cc: Song Liu Cc: Stanislav Fomichev Cc: Yonghong Song Signed-off-by: Andrew Morton

mm: page_alloc: split out FAIL_PAGE_ALLOC

2023-06-09T23:25:23+00:00

... to a single file to reduce a bit of page_alloc.c. Link: https://lkml.kernel.org/r/20230516063821.121844-8-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Iurii Zaikin Cc: Kees Cook Cc: Len Brown Cc: Luis Chamberlain Cc: Mike Rapoport (IBM) Cc: Oscar Salvador Cc: Pavel Machek Cc: Rafael J. Wysocki Signed-off-by: Andrew Morton

fault-inject: allow configuration via configfs

2023-04-13T13:38:54+00:00

This provides a helper function to allow configuration of fault-injection for configfs-based drivers. The config items created by this function have the same interface as the one created under debugfs by fault_create_debugfs_attr(). Signed-off-by: Akinobu Mita Link: https://lore.kernel.org/r/20230327143733.14599-2-akinobu.mita@gmail.com Signed-off-by: Jens Axboe

mm: fix unexpected changes to {failslab|fail_page_alloc}.attr

2022-11-23T02:50:44+00:00

When we specify __GFP_NOWARN, we only expect that no warnings will be issued for current caller. But in the __should_failslab() and __should_fail_alloc_page(), the local GFP flags alter the global {failslab|fail_page_alloc}.attr, which is persistent and shared by all tasks. This is not what we expected, let's fix it. [akpm@linux-foundation.org: unexport should_fail_ex()] Link: https://lkml.kernel.org/r/20221118100011.2634-1-zhengqi.arch@bytedance.com Fixes: 3f913fc5f974 ("mm: fix missing handler for __GFP_NOWARN") Signed-off-by: Qi Zheng Reported-by: Dmitry Vyukov Reviewed-by: Akinobu Mita Reviewed-by: Jason Gunthorpe Cc: Akinobu Mita Cc: Matthew Wilcox Cc: Signed-off-by: Andrew Morton

mm: fix missing handler for __GFP_NOWARN

2022-05-19T21:08:55+00:00

We expect no warnings to be issued when we specify __GFP_NOWARN, but currently in paths like alloc_pages() and kmalloc(), there are still some warnings printed, fix it. But for some warnings that report usage problems, we don't deal with them. If such warnings are printed, then we should fix the usage problems. Such as the following case: WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1)); [zhengqi.arch@bytedance.com: v2] Link: https://lkml.kernel.org/r/20220511061951.1114-1-zhengqi.arch@bytedance.com Link: https://lkml.kernel.org/r/20220510113809.80626-1-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Cc: Akinobu Mita Cc: Vlastimil Babka Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: Steven Rostedt (Google) Signed-off-by: Andrew Morton

mm, fault-injection: declare should_fail_alloc_page()

2022-03-22T22:57:07+00:00

The mm/ directory can almost fully be built with W=1, which would help in local development. One remaining issue is missing prototype for should_fail_alloc_page(). Thus add it next to the should_failslab() prototype. Note the previous attempt by commit f7173090033c ("mm/page_alloc: make should_fail_alloc_page() static") had to be reverted by commit 54aa386661fe as it caused an unresolved symbol error with CONFIG_DEBUG_INFO_BTF=y Link: https://lkml.kernel.org/r/20220314165724.16071-1-vbabka@suse.cz Signed-off-by: Vlastimil Babka Cc: Mel Gorman Cc: Matthew Wilcox Cc: David Hildenbrand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

docs: fault-injection: convert docs to ReST and rename to *.rst

2019-06-14T20:21:07+00:00

The conversion is actually: - add blank lines and identation in order to identify paragraphs; - fix tables markups; - add some lists markups; - mark literal blocks; - adjust title markups. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab Acked-by: Federico Vaga Signed-off-by: Jonathan Corbet

mm: make should_failslab always available for fault injection

2018-04-06T04:36:26+00:00

should_failslab() is a convenient function to hook into for directed error injection into kmalloc(). However, it is only available if a config flag is set. The following BCC script, for example, fails kmalloc() calls after a btrfs umount: from bcc import BPF prog = r""" BPF_HASH(flag); #include int kprobe__btrfs_close_devices(void *ctx) { u64 key = 1; flag.update(&key, &key); return 0; } int kprobe__should_failslab(struct pt_regs *ctx) { u64 key = 1; u64 *res; res = flag.lookup(&key); if (res != 0) { bpf_override_return(ctx, -ENOMEM); } return 0; } """ b = BPF(text=prog) while 1: b.kprobe_poll() This patch refactors the should_failslab implementation so that the function is always available for error injection, independent of flags. This change would be similar in nature to commit f5490d3ec921 ("block: Add should_fail_bio() for bpf error injection"). Link: http://lkml.kernel.org/r/20180222020320.6944-1-hmclauchlan@fb.com Signed-off-by: Howard McLauchlan Reviewed-by: Andrew Morton Cc: Akinobu Mita Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Josef Bacik Cc: Johannes Weiner Cc: Alexei Starovoitov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds