path: root/kernel/debug
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2022-12-02kdb: use srcu console list iteratorJohn Ogness1-2/+16
Guarantee safe iteration of the console list by using SRCU. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Aaron Tomlin <atomlin@atomlin.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20221116162152.193147-15-john.ogness@linutronix.de
2022-09-26mm: remove vmacacheLiam R. Howlett1-12/+0
By using the maple tree and the maple tree state, the vmacache is no longer beneficial and is complicating the VMA code. Remove the vmacache to reduce the work in keeping it up to date and code complexity. Link: https://lkml.kernel.org/r/20220906194824.2110408-26-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-05-26Merge tag 'modules-5.19-rc1' of ↵Linus Torvalds5-56/+0
git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux Pull modules updates from Luis Chamberlain: - It was time to tidy up kernel/module.c and one way of starting with that effort was to split it up into files. At my request Aaron Tomlin spearheaded that effort with the goal to not introduce any functional at all during that endeavour. The penalty for the split is +1322 bytes total, +112 bytes in data, +1210 bytes in text while bss is unchanged. One of the benefits of this other than helping make the code easier to read and review is summoning more help on review for changes with livepatching so kernel/module/livepatch.c is now pegged as maintained by the live patching folks. The before and after with just the move on a defconfig on x86-64: $ size kernel/module.o text data bss dec hex filename 38434 4540 104 43078 a846 kernel/module.o $ size -t kernel/module/*.o text data bss dec hex filename 4785 120 0 4905 1329 kernel/module/kallsyms.o 28577 4416 104 33097 8149 kernel/module/main.o 1158 8 0 1166 48e kernel/module/procfs.o 902 108 0 1010 3f2 kernel/module/strict_rwx.o 3390 0 0 3390 d3e kernel/module/sysfs.o 832 0 0 832 340 kernel/module/tree_lookup.o 39644 4652 104 44400 ad70 (TOTALS) - Aaron added module unload taint tracking (MODULE_UNLOAD_TAINT_TRACKING), to enable tracking unloaded modules which did taint the kernel. - Christophe Leroy added CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC which lets architectures to request having modules data in vmalloc area instead of module area. There are three reasons why an architecture might want this: a) On some architectures (like book3s/32) it is not possible to protect against execution on a page basis. The exec stuff can be mapped by different arch segment sizes (on book3s/32 that is 256M segments). By default the module area is in an Exec segment while vmalloc area is in a NoExec segment. Using vmalloc lets you muck with module data as NoExec on those architectures whereas before you could not. b) By pushing more module data to vmalloc you also increase the probability of module text to remain within a closer distance from kernel core text and this reduces trampolines, this has been reported on arm first and powerpc folks are following that lead. c) Free'ing module_alloc() (Exec by default) area leaves this exposed as Exec by default, some architectures have some security enhancements to set this as NoExec on free, and splitting module data with text let's future generic special allocators be added to the kernel without having developers try to grok the tribal knowledge per arch. Work like Rick Edgecombe's permission vmalloc interface [0] becomes easier to address over time. [0] https://lore.kernel.org/lkml/20201120202426.18009-1-rick.p.edgecombe@intel.com/#r - Masahiro Yamada's symbol search enhancements * tag 'modules-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux: (33 commits) module: merge check_exported_symbol() into find_exported_symbol_in_section() module: do not binary-search in __ksymtab_gpl if fsa->gplok is false module: do not pass opaque pointer for symbol search module: show disallowed symbol name for inherit_taint() module: fix [e_shstrndx].sh_size=0 OOB access module: Introduce module unload taint tracking module: Move module_assert_mutex_or_preempt() to internal.h module: Make module_flags_taint() accept a module's taints bitmap and usable outside core code module.h: simplify MODULE_IMPORT_NS powerpc: Select ARCH_WANTS_MODULES_DATA_IN_VMALLOC on book3s/32 and 8xx module: Remove module_addr_min and module_addr_max module: Add CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC module: Introduce data_layout module: Prepare for handling several RB trees module: Always have struct mod_tree_root module: Rename debug_align() as strict_align() module: Rework layout alignment to avoid BUG_ON()s module: Move module_enable_x() and frob_text() in strict_rwx.c module: Make module_enable_x() independent of CONFIG_ARCH_HAS_STRICT_MODULE_RWX module: Move version support into a separate file ...
2022-05-24lockdown: also lock down previous kgdb useDaniel Thompson2-3/+83
KGDB and KDB allow read and write access to kernel memory, and thus should be restricted during lockdown. An attacker with access to a serial port (for example, via a hypervisor console, which some cloud vendors provide over the network) could trigger the debugger so it is important that the debugger respect the lockdown mode when/if it is triggered. Fix this by integrating lockdown into kdb's existing permissions mechanism. Unfortunately kgdb does not have any permissions mechanism (although it certainly could be added later) so, for now, kgdb is simply and brutally disabled by immediately exiting the gdb stub without taking any action. For lockdowns established early in the boot (e.g. the normal case) then this should be fine but on systems where kgdb has set breakpoints before the lockdown is enacted than "bad things" will happen. CVE: CVE-2022-21499 Co-developed-by: Stephen Brennan <stephen.s.brennan@oracle.com> Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-04-05module: Move kdb module related code out of main kdb codeAaron Tomlin5-56/+0
No functional change. This patch migrates the kdb 'lsmod' command support out of main kdb code into its own file under kernel/module. In addition to the above, a minor style warning i.e. missing a blank line after declarations, was resolved too. The new file was added to MAINTAINERS. Finally we remove linux/module.h as it is entirely redundant. Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
2022-03-24kdb: Fix the putarea helper functionDaniel Thompson1-1/+1
Currently kdb_putarea_size() uses copy_from_kernel_nofault() to write *to* arbitrary kernel memory. This is obviously wrong and means the memory modify ('mm') command is a serious risk to debugger stability: if we poke to a bad address we'll double-fault and lose our debug session. Fix this the (very) obvious way. Note that there are two Fixes: tags because the API was renamed and this patch will only trivially backport as far as the rename (and this is probably enough). Nevertheless Christoph's rename did not introduce this problem so I wanted to record that! Fixes: fe557319aa06 ("maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault") Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)") Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20220128144055.207267-1-daniel.thompson@linaro.org
2021-11-03kdb: Adopt scheduler's task classificationDaniel Thompson4-122/+53
Currently kdb contains some open-coded routines to generate a summary character for each task. This code currently issues warnings, is almost certainly broken and won't make sense to any kernel dev who has ever used /proc to examine task states. Fix both the warning and the potential for confusion by adopting the scheduler's task classification. Whilst doing this we also simplify the filtering by using mask strings directly (which means we don't have to guess all the characters the scheduler might give us). Unfortunately we can't quite match the scheduler classification completely. We add four extra states: - for idle loops and i, m and s for sleeping system daemons (which means kthreads in one of the I, M and S states). These extra states are used to manage the filters for tools to make the output of ps and bta less noisy. Note: The Fixes below is the last point the original dubious code was moved; it was not introduced by that patch. However it gives us the last point to which this patch can be easily backported. Happily that should be enough to cover the introduction of CONFIG_WERROR! Fixes: 2f064a59a11f ("sched: Change task_struct::state") Link: https://lore.kernel.org/r/20211102173158.3315227-1-daniel.thompson@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-09-07Merge tag 'kgdb-5.15-rc1' of ↵Linus Torvalds7-704/+352
git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux Pull kgdb updates from Daniel Thompson: "Changes for kgdb/kdb this cycle are dominated by a change from Sumit that removes as small (256K) private heap from kdb. This is change I've hoped for ever since I discovered how few users of this heap remained in the kernel, so many thanks to Sumit for hunting these down. The other change is an incremental step towards SPDX headers" * tag 'kgdb-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux: kernel: debug: Convert to SPDX identifier kdb: Rename members of struct kdbtab_t kdb: Simplify kdb_defcmd macro logic kdb: Get rid of redundant kdb_register_flags() kdb: Rename struct defcmd_set to struct kdb_macro kdb: Get rid of custom debug heap allocator
2021-09-06kernel: debug: Convert to SPDX identifierCai Huoqing2-8/+2
use SPDX-License-Identifier instead of a verbose license text Signed-off-by: Cai Huoqing <caihuoqing@baidu.com> Link: https://lore.kernel.org/r/20210906112302.937-1-caihuoqing@baidu.com Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-08-19isystem: trim/fixup stdarg.h and other headersAlexey Dobriyan1-1/+0
Delete/fixup few includes in anticipation of global -isystem compile option removal. Note: crypto/aegis128-neon-inner.c keeps <stddef.h> due to redefinition of uintptr_t error (one definition comes from <stddef.h>, another from <linux/types.h>). Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-07-27kdb: Rename members of struct kdbtab_tSumit Garg2-239/+237
Remove redundant prefix "cmd_" from name of members in struct kdbtab_t for better readibility. Suggested-by: Doug Anderson <dianders@chromium.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20210712134620.276667-5-sumit.garg@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-07-27kdb: Simplify kdb_defcmd macro logicSumit Garg1-49/+58
Switch to use a linked list instead of dynamic array which makes allocation of kdb macro and traversing the kdb macro commands list simpler. Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20210712134620.276667-4-sumit.garg@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-07-27kdb: Get rid of redundant kdb_register_flags()Sumit Garg2-127/+53
Commit e4f291b3f7bb ("kdb: Simplify kdb commands registration") allowed registration of pre-allocated kdb commands with pointer to struct kdbtab_t. Lets switch other users as well to register pre- allocated kdb commands via: - Changing prototype for kdb_register() to pass a pointer to struct kdbtab_t instead. - Embed kdbtab_t structure in kdb_macro_t rather than individual params. With these changes kdb_register_flags() becomes redundant and hence removed. Also, since we have switched all users to register pre-allocated commands, "is_dynamic" flag in struct kdbtab_t becomes redundant and hence removed as well. Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20210712134620.276667-3-sumit.garg@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-07-27kdb: Rename struct defcmd_set to struct kdb_macroSumit Garg1-20/+20
Rename struct defcmd_set to struct kdb_macro as that sounds more appropriate given its purpose. Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20210712134620.276667-2-sumit.garg@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-07-27kdb: Get rid of custom debug heap allocatorSumit Garg3-307/+28
Currently the only user for debug heap is kdbnearsym() which can be modified to rather use statically allocated buffer for symbol name as per it's current usage. So do that and hence remove custom debug heap allocator. Note that this change puts a restriction on kdbnearsym() callers to carefully use shared namebuf such that a caller should consume the symbol returned immediately prior to another call to fetch a different symbol. Also, this change uses standard KSYM_NAME_LEN macro for namebuf allocation instead of local variable: knt1_size which should avoid any conflicts caused by changes to KSYM_NAME_LEN macro value. This change has been tested using kgdbtest on arm64 which doesn't show any regressions. Suggested-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20210714055620.369915-1-sumit.garg@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-07-12kernel: debug: Fix unreachable code in gdb_serial_stub()Gustavo A. R. Silva1-1/+1
Fix the following warning: kernel/debug/gdbstub.c:1049:4: warning: fallthrough annotation in unreachable code [-Wimplicit-fallthrough] fallthrough; ^ include/linux/compiler_attributes.h:210:41: note: expanded from macro 'fallthrough' # define fallthrough __attribute__((__fallthrough__) by placing the fallthrough; statement inside ifdeffery. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2021-07-06Merge tag 'kgdb-5.14-rc1' of ↵Linus Torvalds3-6/+7
git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux Pull kgdb updates from Daniel Thompson: "This was a extremely quiet cycle for kgdb. This consists of two patches that between them address spelling errors and a switch fallthrough warning" * tag 'kgdb-5.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux: kgdb: Fix fall-through warning for Clang kgdb: Fix spelling mistakes
2021-06-29Merge tag 'printk-for-5.14' of ↵Linus Torvalds1-8/+1
git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux Pull printk updates from Petr Mladek: - Add %pt[RT]s modifier to vsprintf(). It overrides ISO 8601 separator by using ' ' (space). It produces "YYYY-mm-dd HH:MM:SS" instead of "YYYY-mm-ddTHH:MM:SS". - Correctly parse long row of numbers by sscanf() when using the field width. Add extensive sscanf() selftest. - Generalize re-entrant CPU lock that has already been used to serialize dump_stack() output. It is part of the ongoing printk rework. It will allow to remove the obsoleted printk_safe buffers and introduce atomic consoles. - Some code clean up and sparse warning fixes. * tag 'printk-for-5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: printk: fix cpu lock ordering lib/dump_stack: move cpu lock to printk.c printk: Remove trailing semicolon in macros random32: Fix implicit truncation warning in prandom_seed_state() lib: test_scanf: Remove pointless use of type_min() with unsigned types selftests: lib: Add wrapper script for test_scanf lib: test_scanf: Add tests for sscanf number conversion lib: vsprintf: Fix handling of number field widths in vsscanf lib: vsprintf: scanf: Negative number must have field width > 1 usb: host: xhci-tegra: Switch to use %ptTs nilfs2: Switch to use %ptTs kdb: Switch to use %ptTs lib/vsprintf: Allow to override ISO 8601 date and time separator
2021-06-18sched: Change task_struct::statePeter Zijlstra1-8/+10
Change the type and name of task_struct::state. Drop the volatile and shrink it to an 'unsigned int'. Rename it in order to find all uses such that we can use READ_ONCE/WRITE_ONCE as appropriate. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com> Acked-by: Will Deacon <will@kernel.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20210611082838.550736351@infradead.org
2021-06-01kgdb: Fix fall-through warning for ClangGustavo A. R. Silva1-0/+1
In preparation to enable -Wimplicit-fallthrough for Clang, fix a fall-through warning by explicitly adding a goto statement instead of letting the code fall through to the next case. Link: https://github.com/KSPP/linux/issues/115 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Link: https://lore.kernel.org/r/20210528200222.GA39201@embeddedor Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-06-01kgdb: Fix spelling mistakesZhen Lei3-6/+6
Fix some spelling mistakes in comments: initalization ==> initialization detatch ==> detach represntation ==> representation hexidecimal ==> hexadecimal delimeter ==> delimiter architecure ==> architecture Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> Link: https://lore.kernel.org/r/20210529110305.9446-3-thunder.leizhen@huawei.com Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-05-17kdb: Switch to use %ptTsAndy Shevchenko1-8/+1
Use %ptTs instead of open-coded variant to print contents of time64_t type in human readable form. Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: kgdb-bugreport@lists.sourceforge.net Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20210511153958.34527-2-andriy.shevchenko@linux.intel.com
2021-04-27Merge tag 'printk-for-5.13' of ↵Linus Torvalds1-5/+5
git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux Pull printk updates from Petr Mladek: - Stop synchronizing kernel log buffer readers by logbuf_lock. As a result, the access to the buffer is fully lockless now. Note that printk() itself still uses locks because it tries to flush the messages to the console immediately. Also the per-CPU temporary buffers are still there because they prevent infinite recursion and serialize backtraces from NMI. All this is going to change in the future. - kmsg_dump API rework and cleanup as a side effect of the logbuf_lock removal. - Make bstr_printf() aware that %pf and %pF formats could deference the given pointer. - Show also page flags by %pGp format. - Clarify the documentation for plain pointer printing. - Do not show no_hash_pointers warning multiple times. - Update Senozhatsky email address. - Some clean up. * tag 'printk-for-5.13' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: (24 commits) lib/vsprintf.c: remove leftover 'f' and 'F' cases from bstr_printf() printk: clarify the documentation for plain pointer printing kernel/printk.c: Fixed mundane typos printk: rename vprintk_func to vprintk vsprintf: dump full information of page flags in pGp mm, slub: don't combine pr_err with INFO mm, slub: use pGp to print page flags MAINTAINERS: update Senozhatsky email address lib/vsprintf: do not show no_hash_pointers message multiple times printk: console: remove unnecessary safe buffer usage printk: kmsg_dump: remove _nolock() variants printk: remove logbuf_lock printk: introduce a kmsg_dump iterator printk: kmsg_dumper: remove @active field printk: add syslog_lock printk: use atomic64_t for devkmsg_user.seq printk: use seqcount_latch for clear_seq printk: introduce CONSOLE_LOG_MAX printk: consolidate kmsg_dump_get_buffer/syslog_print_all code printk: refactor kmsg_dump_get_buffer() ...
2021-04-14kdb: Refactor env variables get/set codeSumit Garg1-74/+68
Add two new kdb environment access methods as kdb_setenv() and kdb_printenv() in order to abstract out environment access code from kdb command functions. Also, replace (char *)0 with NULL as an initializer for environment variables array. Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/1612771342-16883-1-git-send-email-sumit.garg@linaro.org [daniel.thompson@linaro.org: Replaced (char *)0/NULL initializers with an array size] Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-03-19kernel: debug: Ordinary typo fixes in the file gdbstub.cBhaskar Chowdhury1-2/+2
s/overwitten/overwritten/ s/procesing/processing/ Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com> Link: https://lore.kernel.org/r/20210317104658.4053473-1-unixbhaskar@gmail.com Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-03-19kdb: Simplify kdb commands registrationSumit Garg3-213/+311
Simplify kdb commands registration via using linked list instead of static array for commands storage. Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Link: https://lore.kernel.org/r/20210224070827.408771-1-sumit.garg@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org> [daniel.thompson@linaro.org: Removed a bunch of .cmd_minline = 0 initializers] Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-03-19kdb: Remove redundant function definitions/prototypesSumit Garg2-20/+0
Cleanup kdb code to get rid of unused function definitions/prototypes. Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Link: https://lore.kernel.org/r/20210224071653.409150-1-sumit.garg@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-03-08printk: kmsg_dump: remove _nolock() variantsJohn Ogness1-4/+4
kmsg_dump_rewind() and kmsg_dump_get_line() are lockless, so there is no need for _nolock() variants. Remove these functions and switch all callers of the _nolock() variants. The functions without _nolock() were chosen because they are already exported to kernel modules. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20210303101528.29901-15-john.ogness@linutronix.de
2021-03-08printk: introduce a kmsg_dump iteratorJohn Ogness1-5/+5
Rather than storing the iterator information in the registered kmsg_dumper structure, create a separate iterator structure. The kmsg_dump_iter structure can reside on the stack of the caller, thus allowing lockless use of the kmsg_dump functions. Update code that accesses the kernel logs using the kmsg_dumper structure to use the new kmsg_dump_iter structure. For kmsg_dumpers, this also means adding a call to kmsg_dump_rewind() to initialize the iterator. All this is in preparation for removal of @logbuf_lock. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Kees Cook <keescook@chromium.org> # pstore Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20210303101528.29901-13-john.ogness@linutronix.de
2021-03-08printk: kmsg_dumper: remove @active fieldJohn Ogness1-1/+1
All 6 kmsg_dumpers do not benefit from the @active flag: (provide their own synchronization) - arch/powerpc/kernel/nvram_64.c - arch/um/kernel/kmsg_dump.c - drivers/mtd/mtdoops.c - fs/pstore/platform.c (only dump on KMSG_DUMP_PANIC, which does not require synchronization) - arch/powerpc/platforms/powernv/opal-kmsg.c - drivers/hv/vmbus_drv.c The other 2 kmsg_dump users also do not rely on @active: (hard-code @active to always be true) - arch/powerpc/xmon/xmon.c - kernel/debug/kdb/kdb_main.c Therefore, @active can be removed. Signed-off-by: John Ogness <john.ogness@linutronix.de> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/20210303101528.29901-12-john.ogness@linutronix.de
2021-02-26kgdb: fix to kill breakpoints on initmem after bootSumit Garg1-0/+11
Currently breakpoints in kernel .init.text section are not handled correctly while allowing to remove them even after corresponding pages have been freed. Fix it via killing .init.text section breakpoints just prior to initmem pages being freed. Doug: "HW breakpoints aren't handled by this patch but it's probably not such a big deal". Link: https://lkml.kernel.org/r/20210224081652.587785-1-sumit.garg@linaro.org Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Suggested-by: Doug Anderson <dianders@chromium.org> Acked-by: Doug Anderson <dianders@chromium.org> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Tested-by: Daniel Thompson <daniel.thompson@linaro.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-11kgdb: Remove kgdb_schedule_breakpoint()Daniel Thompson1-26/+0
To the very best of my knowledge there has never been any in-tree code that calls this function. It exists largely to support an out-of-tree driver that provides kgdb-over-ethernet using the netpoll API. kgdboe has been out-of-tree for more than 10 years and I don't recall any serious attempt to upstream it at any point in the last five. At this stage it looks better to stop carrying this code in the kernel and integrate the code into the out-of-tree driver instead. The long term trajectory for the kernel looks likely to include effort to remove or reduce the use of tasklets (something that has also been true for the last 10 years). Thus the main real reason for this patch is to make explicit that the in-tree kgdb features do not require tasklets. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Link: https://lore.kernel.org/r/20210210142525.2876648-1-daniel.thompson@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org> Acked-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Jason Wessel <jason.wessel@windriver.com>
2021-02-08kdb: Make memory allocations more robustSumit Garg1-1/+1
Currently kdb uses in_interrupt() to determine whether its library code has been called from the kgdb trap handler or from a saner calling context such as driver init. This approach is broken because in_interrupt() alone isn't able to determine kgdb trap handler entry from normal task context. This can happen during normal use of basic features such as breakpoints and can also be trivially reproduced using: echo g > /proc/sysrq-trigger We can improve this by adding check for in_dbg_master() instead which explicitly determines if we are running in debugger context. Cc: stable@vger.kernel.org Signed-off-by: Sumit Garg <sumit.garg@linaro.org> Link: https://lore.kernel.org/r/1611313556-4004-1-git-send-email-sumit.garg@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-02-04kdb: kdb_support: Fix debugging information problemStephen Zhang2-33/+30
There are several common patterns. 0: kdb_printf("...",...); which is the normal one. 1: kdb_printf("%s: "...,__func__,...) We could improve '1' to this : #define kdb_func_printf(format, args...) \ kdb_printf("%s: " format, __func__, ## args) 2: if(KDB_DEBUG(AR)) kdb_printf("%s "...,__func__,...); We could improve '2' to this : #define kdb_dbg_printf(mask, format, args...) \ do { \ if (KDB_DEBUG(mask)) \ kdb_func_printf(format, ## args); \ } while (0) In addition, we changed the format code of size_t to %zu. Signed-off-by: Stephen Zhang <stephenzhangzsd@gmail.com> Link: https://lore.kernel.org/r/1612440429-6391-1-git-send-email-stephenzhangzsd@gmail.com Reviewed-by: Douglas Anderson <dianders@chromium.org> [daniel.thompson@linaro.org: Minor typo and line length fixes in the patch description] Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-02-04kernel: debug: fix typo issuewengjianfeng1-2/+2
change 'regster' to 'register'. Signed-off-by: wengjianfeng <wengjianfeng@yulong.com> Link: https://lore.kernel.org/r/20210203081034.9004-1-samirweng1979@163.com Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2021-02-04kgdb: rectify kernel-doc for kgdb_unregister_io_module()Lukas Bulwahn1-1/+1
The command 'find ./kernel/debug/ | xargs ./scripts/kernel-doc -none' reported a typo in the kernel-doc of kgdb_unregister_io_module(). Rectify the kernel-doc, such that no issues remain for ./kernel/debug/. Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Link: https://lore.kernel.org/r/20210125144847.21896-1-lukas.bulwahn@gmail.com Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-11-24smp: Cleanup smp_call_function*()Peter Zijlstra1-3/+3
Get rid of the __call_single_node union and cleanup the API a little to avoid external code relying on the structure layout as much. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
2020-10-01kdb: Fix pager search for multi-line stringsDaniel Thompson1-2/+6
Currently using forward search doesn't handle multi-line strings correctly. The search routine replaces line breaks with \0 during the search and, for regular searches ("help | grep Common\n"), there is code after the line has been discarded or printed to replace the break character. However during a pager search ("help\n" followed by "/Common\n") when the string is matched we will immediately return to normal output and the code that should restore the \n becomes unreachable. Fix this by restoring the replaced character when we disable the search mode and update the comment accordingly. Fixes: fb6daa7520f9d ("kdb: Provide forward search at more prompt") Link: https://lore.kernel.org/r/20200909141708.338273-1-daniel.thompson@linaro.org Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-10-01kernel: debug: Centralize dbg_[de]activate_sw_breakpointsDaniel Thompson3-3/+2
During debug trap execution we expect dbg_deactivate_sw_breakpoints() to be paired with an dbg_activate_sw_breakpoint(). Currently although the calls are paired correctly they are needlessly smeared across three different functions. Worse this also results in code to drive polled I/O being called with breakpoints activated which, in turn, needlessly increases the set of functions that will recursively trap if breakpointed. Fix this by moving the activation of breakpoints into the debug core. Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200927211531.1380577-4-daniel.thompson@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-10-01kgdb: Add NOKPROBE labels on the trap handler functionsDaniel Thompson1-0/+16
Currently kgdb honours the kprobe blocklist but doesn't place its own trap handling code on the list. Add labels to discourage attempting to use kgdb to debug itself. Not every functions that executes from the trap handler needs to be marked up: relatively early in the trap handler execution (just after we bring the other CPUs to a halt) all breakpoints are replaced with the original opcodes. This patch marks up code in the debug_core that executes between trap entry and the breakpoints being deactivated and, also, code that executes between breakpoint activation and trap exit. To be clear these changes are not sufficient to make recursive trapping impossible since they do not include library calls made during kgdb's entry/exit logic. However going much further whilst we are sharing the kprobe blocklist risks reducing the capabilities of kprobe and this would be a bad trade off (especially so given kgdb's users are currently conditioned to avoid recursive traps). Reviewed-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200927211531.1380577-3-daniel.thompson@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-09-28kgdb: Honour the kprobe blocklist when setting breakpointsDaniel Thompson2-0/+13
Currently kgdb has absolutely no safety rails in place to discourage or prevent a user from placing a breakpoint in dangerous places such as the debugger's own trap entry/exit and other places where it is not safe to take synchronous traps. Introduce a new config symbol KGDB_HONOUR_BLOCKLIST and modify the default implementation of kgdb_validate_break_address() so that we use the kprobe blocklist to prohibit instrumentation of critical functions if the config symbol is set. The config symbol dependencies are set to ensure that the blocklist will be enabled by default if we enable KGDB and are compiling for an architecture where we HAVE_KPROBES. Suggested-by: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lore.kernel.org/r/20200927211531.1380577-2-daniel.thompson@linaro.org Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-09-11kernel/debug: Fix spelling mistake in debug_core.cYouling Tang1-2/+2
Fix typo: "notifiter" --> "notifier" "overriden" --> "overridden" Signed-off-by: Youling Tang <tangyouling@loongson.cn> Link: https://lore.kernel.org/r/1596793480-22559-1-git-send-email-tangyouling@loongson.cn Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-09-08kdb: Use newer api for tasklist scanningDavidlohr Bueso4-12/+8
This kills using the do_each_thread/while_each_thread combo to iterate all threads and uses for_each_process_thread() instead, maintaining semantics. while_each_thread() is ultimately racy and deprecated; although in this particular case there is no concurrency so it doesn't matter. Still lets trivially get rid of two more users. Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Link: https://lore.kernel.org/r/20200907203206.21293-1-dave@stgolabs.net Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-09-08kgdb: Make "kgdbcon" work properly with "kgdb_earlycon"Douglas Anderson1-8/+14
On my system the kernel processes the "kgdb_earlycon" parameter before the "kgdbcon" parameter. When we setup "kgdb_earlycon" we'll end up in kgdb_register_callbacks() and "kgdb_use_con" won't have been set yet so we'll never get around to starting "kgdbcon". Let's remedy this by detecting that the IO module was already registered when setting "kgdb_use_con" and registering the console then. As part of this, to avoid pre-declaring things, move the handling of the "kgdbcon" further down in the file. Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://lore.kernel.org/r/20200630151422.1.I4aa062751ff5e281f5116655c976dff545c09a46@changeid Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-09-08kdb: remove unnecessary null check of dbg_io_opsCengiz Can1-7/+7
`kdb_msg_write` operates on a global `struct kgdb_io *` called `dbg_io_ops`. It's initialized in `debug_core.c` and checked throughout the debug flow. There's a null check in `kdb_msg_write` which triggers static analyzers and gives the (almost entirely wrong) impression that it can be null. Coverity scanner caught this as CID 1465042. I have removed the unnecessary null check and eliminated false-positive forward null dereference warning. Signed-off-by: Cengiz Can <cengiz@kernel.wtf> Link: https://lore.kernel.org/r/20200630082922.28672-1-cengiz@kernel.wtf Reviewed-by: Sumit Garg <sumit.garg@linaro.org> Reviewed-by: Douglas Anderson <dianders@chromium.org> Tested-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
2020-08-23treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva3-8/+8
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-04Merge tag 'uninit-macro-v5.9-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull uninitialized_var() macro removal from Kees Cook: "This is long overdue, and has hidden too many bugs over the years. The series has several "by hand" fixes, and then a trivial treewide replacement. - Clean up non-trivial uses of uninitialized_var() - Update documentation and checkpatch for uninitialized_var() removal - Treewide removal of uninitialized_var()" * tag 'uninit-macro-v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: compiler: Remove uninitialized_var() macro treewide: Remove uninitialized_var() usage checkpatch: Remove awareness of uninitialized_var() macro mm/debug_vm_pgtable: Remove uninitialized_var() usage f2fs: Eliminate usage of uninitialized_var() macro media: sur40: Remove uninitialized_var() usage KVM: PPC: Book3S PR: Remove uninitialized_var() usage clk: spear: Remove uninitialized_var() usage clk: st: Remove uninitialized_var() usage spi: davinci: Remove uninitialized_var() usage ide: Remove uninitialized_var() usage rtlwifi: rtl8192cu: Remove uninitialized_var() usage b43: Remove uninitialized_var() usage drbd: Remove uninitialized_var() usage x86/mm/numa: Remove uninitialized_var() usage docs: deprecated.rst: Add uninitialized_var()
2020-07-30treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD()Kees Cook1-1/+1
This converts all the existing DECLARE_TASKLET() (and ...DISABLED) macros with DECLARE_TASKLET_OLD() in preparation for refactoring the tasklet callback type. All existing DECLARE_TASKLET() users had a "0" data argument, it has been removed here as well. Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-16treewide: Remove uninitialized_var() usageKees Cook1-1/+1
Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. In preparation for removing[2] the[3] macro[4], remove all remaining needless uses with the following script: git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \ xargs perl -pi -e \ 's/\buninitialized_var\(([^\)]+)\)/\1/g; s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;' drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid pathological white-space. No outstanding warnings were found building allmodconfig with GCC 9.3.0 for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64, alpha, and m68k. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Reviewed-by: Leon Romanovsky <leonro@mellanox.com> # drivers/infiniband and mlx4/mlx5 Acked-by: Jason Gunthorpe <jgg@mellanox.com> # IB Acked-by: Kalle Valo <kvalo@codeaurora.org> # wireless drivers Reviewed-by: Chao Yu <yuchao0@huawei.com> # erofs Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-09kgdb: enable arch to support XML packet.Vincent Chen1-0/+13
The XML packet could be supported by required architecture if the architecture defines CONFIG_HAVE_ARCH_KGDB_QXFER_PKT and implement its own kgdb_arch_handle_qxfer_pkt(). Except for the kgdb_arch_handle_qxfer_pkt(), the architecture also needs to record the feature supported by gdb stub into the kgdb_arch_gdb_stub_feature, and these features will be reported to host gdb when gdb stub receives the qSupported packet. Signed-off-by: Vincent Chen <vincent.chen@sifive.com> Acked-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

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