kernel/linux.git/drivers/tty/sysrq.c, branch v4.14.286

sysrq: Remove duplicated sysrq message

2020-03-11T17:02:46+00:00

commit c3fee60908db4a8594f2e4a2131998384b8fa006 upstream. The commit 97f5f0cd8cd0a0544 ("Input: implement SysRq as a separate input handler") added pr_fmt() definition. It caused a duplicated message prefix in the sysrq header messages, for example: [ 177.053931] sysrq: SysRq : Show backtrace of all active CPUs [ 742.864776] sysrq: SysRq : HELP : loglevel(0-9) reboot(b) crash(c) Fixes: 97f5f0cd8cd0a05 ("Input: implement SysRq as a separate input handler") Signed-off-by: Petr Mladek Reviewed-by: Sergey Senozhatsky Cc: Tommi Rantala Signed-off-by: Greg Kroah-Hartman

sysrq: Restore original console_loglevel when sysrq disabled

2020-03-11T17:02:46+00:00

commit 075e1a0c50f59ea210561d0d0fedbd945615df78 upstream. The sysrq header line is printed with an increased loglevel to provide users some positive feedback. The original loglevel is not restored when the sysrq operation is disabled. This bug was introduced in 2.6.12 (pre-git-history) by the commit ("Allow admin to enable only some of the Magic-Sysrq functions"). Signed-off-by: Petr Mladek Reviewed-by: Sergey Senozhatsky Reviewed-by: Steven Rostedt (VMware) Cc: Tommi Rantala Signed-off-by: Greg Kroah-Hartman

sysrq : fix Show Regs call trace on ARM

2017-12-10T12:40:42+00:00

[ Upstream commit b00bebbc301c8e1f74f230dc82282e56b7e7a6db ] When kernel configuration SMP,PREEMPT and DEBUG_PREEMPT are enabled, echo 1 >/proc/sys/kernel/sysrq echo p >/proc/sysrq-trigger kernel will print call trace as below: sysrq: SysRq : Show Regs BUG: using __this_cpu_read() in preemptible [00000000] code: sh/435 caller is __this_cpu_preempt_check+0x18/0x20 Call trace: [] dump_backtrace+0x0/0x1d0 [] show_stack+0x24/0x30 [] dump_stack+0x90/0xb0 [] check_preemption_disabled+0x100/0x108 [] __this_cpu_preempt_check+0x18/0x20 [] sysrq_handle_showregs+0x1c/0x40 [] __handle_sysrq+0x12c/0x1a0 [] write_sysrq_trigger+0x60/0x70 [] proc_reg_write+0x90/0xd0 [] __vfs_write+0x48/0x90 [] vfs_write+0xa4/0x190 [] SyS_write+0x54/0xb0 [] el0_svc_naked+0x24/0x28 This can be seen on a common board like an r-pi3. This happens because when echo p >/proc/sysrq-trigger, get_irq_regs() is called outside of IRQ context, if preemption is enabled in this situation,kernel will print the call trace. Since many prior discussions on the mailing lists have made it clear that get_irq_regs either just returns NULL or stale data when used outside of IRQ context,we simply avoid calling it outside of IRQ context. Signed-off-by: Jibin Xu Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

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

oom: improve oom disable handling

2017-05-03T22:52:10+00:00

Tetsuo has reported that sysrq triggered OOM killer will print a misleading information when no tasks are selected: sysrq: SysRq : Manual OOM execution Out of memory: Kill process 4468 ((agetty)) score 0 or sacrifice child Killed process 4468 ((agetty)) total-vm:43704kB, anon-rss:1760kB, file-rss:0kB, shmem-rss:0kB sysrq: SysRq : Manual OOM execution Out of memory: Kill process 4469 (systemd-cgroups) score 0 or sacrifice child Killed process 4469 (systemd-cgroups) total-vm:10704kB, anon-rss:120kB, file-rss:0kB, shmem-rss:0kB sysrq: SysRq : Manual OOM execution sysrq: OOM request ignored because killer is disabled sysrq: SysRq : Manual OOM execution sysrq: OOM request ignored because killer is disabled sysrq: SysRq : Manual OOM execution sysrq: OOM request ignored because killer is disabled The real reason is that there are no eligible tasks for the OOM killer to select but since commit 7c5f64f84483 ("mm: oom: deduplicate victim selection code for memcg and global oom") the semantic of out_of_memory has changed without updating moom_callback. This patch updates moom_callback to tell that no task was eligible which is the case for both oom killer disabled and no eligible tasks. In order to help distinguish first case from the second add printk to both oom_killer_{enable,disable}. This information is useful on its own because it might help debugging potential memory allocation failures. Fixes: 7c5f64f84483 ("mm: oom: deduplicate victim selection code for memcg and global oom") Link: http://lkml.kernel.org/r/20170404134705.6361-1-mhocko@kernel.org Signed-off-by: Michal Hocko Reported-by: Tetsuo Handa Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

net: ibm: emac: remove unused sysrq handler for 'c' key

2017-04-05T14:26:18+00:00

Since commit d6580a9f1523 ("kexec: sysrq: simplify sysrq-c handler"), the sysrq handler for the 'c' key has been sysrq_crash_op. Debugging code in the ibm_emac driver also tries to register a handler for the 'c' key, but this has no effect because register_sysrq_key() doesn't replace existing handlers. Since evidently no one has cared enough to fix this in the last 8 years, and it's very rare for drivers to register sysrq handlers (for good reason), just remove the dead code. Signed-off-by: Eric Biggers Signed-off-by: David S. Miller

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:35+00:00

We are going to split out of , which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder file that just maps to to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:34+00:00

sched/headers: Prepare for new header dependencies before moving code to

2017-03-02T07:42:29+00:00

lib/show_mem.c: teach show_mem to work with the given nodemask

2017-02-23T00:41:30+00:00

show_mem() allows to filter out node specific data which is irrelevant to the allocation request via SHOW_MEM_FILTER_NODES. The filtering is done in skip_free_areas_node which skips all nodes which are not in the mems_allowed of the current process. This works most of the time as expected because the nodemask shouldn't be outside of the allocating task but there are some exceptions. E.g. memory hotplug might want to request allocations from outside of the allowed nodes (see new_node_page). Get rid of this hardcoded behavior and push the allocation mask down the show_mem path and use it instead of cpuset_current_mems_allowed. NULL nodemask is interpreted as cpuset_current_mems_allowed. [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20170117091543.25850-5-mhocko@kernel.org Signed-off-by: Michal Hocko Acked-by: Mel Gorman Cc: Hillf Danton Cc: Johannes Weiner Cc: Vlastimil Babka Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds