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2018-03-29um: Compile with modern headersJason A. Donenfeld2-0/+2
Recent libcs have gotten a bit more strict, so we actually need to include the right headers and use the right types. This enables UML to compile again. Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Cc: stable@vger.kernel.org Signed-off-by: Richard Weinberger <richard@nod.at>
2018-02-19Epoll based IRQ controllerAnton Ivanov1-95/+107
1. Removes the need to walk the IRQ/Device list to determine who triggered the IRQ. 2. Improves scalability (up to several times performance improvement for cases with 10s of devices). 3. Improves UML baseline IO performance for one disk + one NIC use case by up to 10%. 4. Introduces write poll triggered IRQs. 5. Prerequisite for introducing high performance mmesg family of functions in network IO. 6. Fixes RNG shutdown which was leaking a file descriptor Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2018-02-19um: Use POSIX ucontext_t instead of struct ucontextKrzysztof Mazur1-1/+1
glibc 2.26 removed the 'struct ucontext' to "improve" POSIX compliance and break programs, including User Mode Linux. Fix User Mode Linux by using POSIX ucontext_t. This fixes: arch/um/os-Linux/signal.c: In function 'hard_handler': arch/um/os-Linux/signal.c:163:22: error: dereferencing pointer to incomplete type 'struct ucontext' mcontext_t *mc = &uc->uc_mcontext; arch/x86/um/stub_segv.c: In function 'stub_segv_handler': arch/x86/um/stub_segv.c:16:13: error: dereferencing pointer to incomplete type 'struct ucontext' &uc->uc_mcontext); Cc: stable@vger.kernel.org Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2-0/+2
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 <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-13um: return negative in tuntap_open_tramp()Dan Carpenter1-1/+1
The intention is to return negative error codes. "pid" is already negative but we accidentally negate it again back to positive. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-09-13Fix minor typos and grammar in UML start_up helpJames Pack1-3/+3
Signed-off-by: James Pack <jpack61108@gmail.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-09-13um: Fix FP register size for XSTATE/XSAVEThomas Meyer1-9/+8
Hard code max size. Taken from https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=gdb/common/x86-xstate.h Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-07-07um: Add kerneldoc for userspace_tramp() and start_userspace()Thomas Meyer1-1/+30
Also use correct function name spelling (stub_segv_handler) for better grepping Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-07-07um: userspace - be more verbose in ptrace set regs errorThomas Meyer1-2/+8
When ptrace fails to set GP/FP regs for the target process, log the error before crashing the UML kernel. Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-07-05um: Use os_warn to print out pre-boot warning/error messagesMasami Hiramatsu5-14/+14
Use os_warn() instead of printf/fprintf to print out pre-boot warning/error messages to stderr. Note that the help message and version message are kept to print out to stdout, because user explicitly specifies those options to get such information. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-07-05um: Add os_warn() for pre-boot warning/error messagesMasami Hiramatsu1-0/+9
Add os_warn() for printing out pre-boot warning/error messages in stderr. The messages via os_warn() are not suppressed by quiet option. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-07-05um: Use os_info for the messages on normal pathMasami Hiramatsu3-23/+24
Use os_info() for printing out the messages on the normal execution path. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-07-05um: Add os_info() for pre-boot information messagesMasami Hiramatsu1-0/+25
Add os_info() for printing out pre-boot information level messages in stderr. The messages via os_info() are suppressed by "quiet" kernel command line. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-07-05um: Use printk instead of printf in make_uml_dirMasami Hiramatsu1-4/+7
Since this function will be called after printk buffer initialized, use printk as other functions do. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-05-04um: Add missing NR_CPUS includeRichard Weinberger1-0/+1
We need linux/threads.h for that variable. Fixes: 8bba077066d6d0 ("um: Set number of CPUs") Signed-off-by: Richard Weinberger <richard@nod.at>
2017-05-03um: Set number of CPUsNikola Kotur1-3/+0
Define NR_CPUS required by the timer subsystem. Fixes this make warning: scripts/kconfig/conf --oldconfig arch/x86/um/Kconfig kernel/time/Kconfig:155:warning: range is invalid Signed-off-by: Nikola Kotur <kotnick@gmail.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2016-08-04um: Support kcovVegard Nossum1-0/+3
This adds support for kcov to UML. There is a small problem where UML will randomly segfault during boot; this is because current_thread_info() occasionally returns an invalid (non-NULL) pointer and we try to dereference it in __sanitizer_cov_trace_pc(). I consider this a bug in UML itself and this patch merely exposes it. [v2: disable instrumentation in UML-specific code] Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Meyer <thomas@m3y3r.de> Cc: user-mode-linux-devel <user-mode-linux-devel@lists.sourceforge.net> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2016-08-04um: Fix possible deadlock in sig_handler_common()Richard Weinberger1-2/+3
We are in atomic context and must not sleep. Sleeping here is possible since malloc() maps to kmalloc() with GFP_KERNEL. Cc: stable@vger.kernel.org Fixes: b6024b21 ("um: extend fpstate to _xstate to support YMM registers") Signed-off-by: Richard Weinberger <richard@nod.at>
2016-05-21um: extend fpstate to _xstate to support YMM registersEli Cooper1-8/+20
Extends fpstate to _xstate, in order to hold AVX/YMM registers. To avoid oversized stack frame, the following functions have been refactored by using malloc. - sig_handler_common - timer_real_alarm_handler Signed-off-by: Eli Cooper <elicooper@gmx.com>
2016-01-10um: Use race-free temporary file creationMickaël Salaün1-0/+11
Open the memory mapped file with the O_TMPFILE flag when available. Signed-off-by: Mickaël Salaün <mic@digikod.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Acked-by: Tristan Schmelcher <tschmelcher@google.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2016-01-10um: Do not set unsecure permission for temporary fileMickaël Salaün1-6/+0
Remove the insecure 0777 mode for temporary file to prohibit other users to change the executable mapped code. An attacker could gain access to the mapped file descriptor from the temporary file (before it is unlinked) in a read-only mode but it should not be accessible in write mode to avoid arbitrary code execution. To not change the hostfs behavior, the temporary file creation permission now depends on the current umask(2) and the implementation of mkstemp(3). Signed-off-by: Mickaël Salaün <mic@digikod.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Acked-by: Tristan Schmelcher <tschmelcher@google.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2016-01-10um: Fix ptrace GETREGS/SETREGS bugsMickaël Salaün1-7/+0
This fix two related bugs: * PTRACE_GETREGS doesn't get the right orig_ax (syscall) value * PTRACE_SETREGS can't set the orig_ax value (erased by initial value) Get rid of the now useless and error-prone get_syscall(). Fix inconsistent behavior in the ptrace implementation for i386 when updating orig_eax automatically update the syscall number as well. This is now updated in handle_syscall(). Signed-off-by: Mickaël Salaün <mic@digikod.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kees Cook <keescook@chromium.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will Drewry <wad@chromium.org> Cc: Thomas Meyer <thomas@m3y3r.de> Cc: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Cc: Anton Ivanov <aivanov@brocade.com> Cc: Meredydd Luff <meredydd@senatehouse.org> Cc: David Drysdale <drysdale@google.com> Signed-off-by: Richard Weinberger <richard@nod.at> Acked-by: Kees Cook <keescook@chromium.org>
2016-01-10um: Update UBD to use pread/pwrite family of functionsAnton Ivanov1-0/+19
This decreases the number of syscalls per read/write by half. Signed-off-by: Anton Ivanov <aivanov@brocade.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2016-01-10um: Prevent IRQ handler reentrancyAnton Ivanov1-1/+15
The existing IRQ handler design in UML does not prevent reentrancy This is mitigated by fd-enable/fd-disable semantics for the IO portion of the UML subsystem. The timer, however, can and is re-entered resulting in very deep stack usage and occasional stack exhaustion. This patch prevents this by checking if there is a timer interrupt in-flight before processing any pending timer interrupts. Signed-off-by: Anton Ivanov <aivanov@brocade.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2016-01-10uml: flush stdout before forkingVegard Nossum1-0/+2
I was seeing some really weird behaviour where piping UML's output somewhere would cause output to get duplicated: $ ./vmlinux | head -n 40 Checking that ptrace can change system call numbers...Core dump limits : soft - 0 hard - NONE OK Checking syscall emulation patch for ptrace...Core dump limits : soft - 0 hard - NONE OK Checking advanced syscall emulation patch for ptrace...Core dump limits : soft - 0 hard - NONE OK Core dump limits : soft - 0 hard - NONE This is because these tests do a fork() which duplicates the non-empty stdout buffer, then glibc flushes the duplicated buffer as each child exits. A simple workaround is to flush before forking. Cc: stable@vger.kernel.org Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2015-11-06um: Switch clocksource to hrtimersAnton Ivanov6-181/+168
UML is using an obsolete itimer call for all timers and "polls" for kernel space timer firing in its userspace portion resulting in a long list of bugs and incorrect behaviour(s). It also uses ITIMER_VIRTUAL for its timer which results in the timer being dependent on it running and the cpu load. This patch fixes this by moving to posix high resolution timers firing off CLOCK_MONOTONIC and relaying the timer correctly to the UML userspace. Fixes: - crashes when hosts suspends/resumes - broken userspace timers - effecive ~40Hz instead of what they should be. Note - this modifies skas behavior by no longer setting an itimer per clone(). Timer events are relayed instead. - kernel network packet scheduling disciplines - tcp behaviour especially under load - various timer related corner cases Finally, overall responsiveness of userspace is better. Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Anton Ivanov <aivanov@brocade.com> [rw: massaged commit message] Signed-off-by: Richard Weinberger <richard@nod.at>
2015-11-06um: Store syscall number after syscall_trace_enter()Richard Weinberger1-3/+7
To support changing syscall numbers we have to store it after syscall_trace_enter(). Signed-off-by: Richard Weinberger <richard@nod.at>
2015-10-19um: Fix waitpid() usage in helper codeRichard Weinberger1-3/+3
If UML is executing a helper program it is using waitpid() with the __WCLONE flag to wait for the program as the helper is executed from a clone()'ed thread. While using __WCLONE is perfectly fine for clone()'ed childs it won't detect terminated childs if the helper has issued an execve(). We have to use __WALL to wait for both clone()'ed and regular childs to detect the termination before and after an execve(). Reported-and-tested-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Richard Weinberger <richard@nod.at>
2015-06-28Merge branch 'for-linus-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/umlLinus Torvalds5-13/+16
Pull UML updates from Richard Weinberger: - remove hppfs ("HonePot ProcFS") - initial support for musl libc - uaccess cleanup - random cleanups and bug fixes all over the place * 'for-linus-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: (21 commits) um: Don't pollute kernel namespace with uapi um: Include sys/types.h for makedev(), major(), minor() um: Do not use stdin and stdout identifiers for struct members um: Do not use __ptr_t type for stack_t's .ss pointer um: Fix mconsole dependency um: Handle tracehook_report_syscall_entry() result um: Remove copy&paste code from init.h um: Stop abusing __KERNEL__ um: Catch unprotected user memory access um: Fix warning in setup_signal_stack_si() um: Rework uaccess code um: Add uaccess.h to ldt.c um: Add uaccess.h to syscalls_64.c um: Add asm/elf.h to vma.c um: Cleanup mem_32/64.c headers um: Remove hppfs um: Move syscall() declaration into os.h um: kernel: ksyms: Export symbol syscall() for fixing modpost issue um/os-Linux: Use char[] for syscall_stub declarations um: Use char[] for linker script address declarations ...
2015-06-25um: Include sys/types.h for makedev(), major(), minor()Hans-Werner Hilse1-0/+1
The functions in question are not part of the POSIX standard, documentation however hints that the corresponding header shall be sys/types.h. C libraries other than glibc, namely musl, did not include that header via other ways and complained. Signed-off-by: Hans-Werner Hilse <hwhilse@gmail.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2015-06-25um: Do not use stdin and stdout identifiers for struct membersHans-Werner Hilse1-3/+3
stdin, stdout and stderr are macros according to C89/C99. Thus do not use them as struct member identifiers to avoid bad results from macro expansion. Signed-off-by: Hans-Werner Hilse <hwhilse@gmail.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2015-06-25um: Do not use __ptr_t type for stack_t's .ss pointerHans-Werner Hilse1-3/+5
__ptr_t type is a glibc-specific type, while the generally documented type is a void*. That's what other C libraries use, too. Signed-off-by: Hans-Werner Hilse <hwhilse@gmail.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2015-05-31um/os-Linux: Use char[] for syscall_stub declarationsNicolas Iooss2-7/+7
When declaring __syscall_stub_start, use the same type in UML userspace code as in arch/um/include/asm/sections.h. While at it, also declare batch_syscall_stub as char[]. Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org> Signed-off-by: Richard Weinberger <richard@nod.at>
2015-05-24um,ethertap: use strncpyAlan1-1/+1
[um maintainers appear to be vanished] I can't prove the case pointed out in https://bugzilla.kernel.org/show_bug.cgi?id=82341 is correct so let us play safe. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-04-13um: Move uml_postsetup in the init_thread stackThomas Meyer1-1/+1
atomic_notifier_chain_register() and uml_postsetup() do call kernel code that rely on the "current" kernel macro and a valid task_struct resp. thread_info struct. Give those functions a valid stack by moving uml_postsetup() in the init_thread stack. This moves enables a panic() call in this early code to generate a valid stacktrace, instead of crashing. E.g. when an UML kernel is started with an initrd but too few physical memory the panic() call get's actually processed. Signed-off-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Richard Weinberger <richard@nod.at>
2015-04-13um: Remove SKAS3/4 supportRichard Weinberger4-408/+62
Before we had SKAS0 UML had two modes of operation TT (tracing thread) and SKAS3/4 (separated kernel address space). TT was known to be insecure and got removed a long time ago. SKAS3/4 required a few (3 or 4) patches on the host side which never went mainline. The last host patch is 10 years old. With SKAS0 mode (separated kernel address space using 0 host patches), default since 2005, SKAS3/4 is obsolete and can be removed. Signed-off-by: Richard Weinberger <richard@nod.at>
2014-07-20Revert "um: Fix wait_stub_done() error handling"Richard Weinberger1-7/+2
This reverts commit 0974a9cadc7886f7baaa458bb0c89f5c5f9d458e. The real for for that issue is to release current->mm->mmap_sem in fix_range_common(). Signed-off-by: Richard Weinberger <richard@nod.at>
2014-04-20um: Memory corruption on startupAnton Ivanov1-0/+6
The reverse case of this race (you must msync before read) is well known. This is the not so common one. It can be triggered only on systems which do a lot of task switching and only at UML startup. If you are starting 200+ UMLs ~ 0.5% will always die without this fix. Signed-off-by: Anton Ivanov <antivano@cisco.com> [rw: minor whitespace fixes] Signed-off-by: Richard Weinberger <richard@nod.at>
2014-04-20um: Missing pipe handlingAnton Ivanov1-0/+1
UML does not handle sigpipe. As a result when running it under expect or redirecting the IO from the console to an external program it will crash if the program stops or exits. Signed-off-by: Anton Ivanov <antivano@cisco.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2014-04-20uml: Simplify tempdir logic.Tristan Schmelcher1-297/+75
Inferring the mount hierarchy correctly from /proc/mounts is hard when MS_MOVE may have been used, and the previous code did it wrongly. This change simplifies the logic to only require that /dev/shm be _on_ tmpfs (which can be checked trivially with statfs) rather than that it be a _mountpoint_ of tmpfs, since there isn't a compelling reason to be that strict. We also now check for tmpfs on whatever directory we ultimately use so that the user is better informed. This change also moves the more standard TMPDIR environment variable check ahead of the others. Applies to 3.12. Signed-off-by: Tristan Schmelcher <tschmelcher@google.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2013-11-17um: Make stack trace reliable against kernel mode faultsRichard Weinberger1-0/+8
As UML uses an alternative signal stack we cannot use the current stack pointer for stack dumping if UML itself dies by SIGSEGV. To bypass this issue we save regs taken from mcontext in our segv handler into thread_struct and use these regs to obtain the stack pointer in show_stack(). Signed-off-by: Richard Weinberger <richard@nod.at>
2013-09-07um: Run UML in it's own session.Richard Weinberger1-0/+2
If UML is not run by a shell it can happen that UML will kill unrelated proceses upon a fatal exit because it issues a kill(0, ...). To prevent such oddities we create a new session in main(). Reported-and-tested-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2013-09-07um: Cleanup SIGTERM handlingRichard Weinberger4-5/+13
Richard reported that some UML processes survive if the UML main process receives a SIGTERM. This issue was caused by a wrongly placed signal(SIGTERM, SIG_DFL) in init_new_thread_signals(). It disabled the UML exit handler accidently for some processes. The correct solution is to disable the fatal handler for all UML helper threads/processes. Such that last_ditch_exit() does not get called multiple times and all processes can exit due to SIGTERM. Reported-and-tested-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2013-09-07um: ubd: Add REQ_FLUSH suppportRichard Weinberger1-0/+9
UML's block device driver does not support write barriers, to support this this patch adds REQ_FLUSH suppport. Every time the block layer sends a REQ_FLUSH we fsync() now our backing file to guarantee data consistency. Reported-and-tested-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2013-09-07um: Implement probe_kernel_read()Richard Weinberger1-0/+52
UML needs it's own probe_kernel_read() to handle kernel mode faults correctly. The implementation uses mincore() on the host side to detect whether a page is owned by the UML kernel process. This fixes also a possible crash when sysrq-t is used. Starting with 3.10 sysrq-t calls probe_kernel_read() to read details from the kernel workers. As kernel worker are completely async pointers may turn NULL while reading them. Cc: <stian@nixia.no> Cc: <tj@kernel.org> Cc: <stable@vger.kernel.org> # 3.10.x Signed-off-by: Richard Weinberger <richard@nod.at>
2013-07-19um: siginfo cleanupRichard Weinberger2-9/+9
Currently we use both struct siginfo and siginfo_t. Let's use struct siginfo internally to avoid ongoing compiler warning. We are allowed to do so because struct siginfo and siginfo_t are equivalent. Signed-off-by: Richard Weinberger <richard@nod.at>
2013-07-19uml: Fix which_tmpdir failure when /dev/shm is a symlink, and in other edge casesTristan Schmelcher1-41/+189
which_tmpdir did the wrong thing if /dev/shm was a symlink (e.g., to /run/shm), if there were multiple mounts on top of each other, if the mount(s) were obscured by a later mount, or if /dev/shm was a prefix of another mount point. This fixes these cases. Applies to 3.9.6. Signed-off-by: Tristan Schmelcher <tschmelcher@google.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2013-07-19um: Fix wait_stub_done() error handlingRichard Weinberger1-2/+7
If we die within a stub handler we only way to reliable kill the (obviously) dying uml guest process is killing it's host twin on the host side. Signed-off-by: Richard Weinberger <richard@nod.at>
2013-05-02Merge commit '8700c95adb03' into timers/nohzFrederic Weisbecker2-1/+3
The full dynticks tree needs the latest RCU and sched upstream updates in order to fix some dependencies. Merge a common upstream merge point that has these updates. Conflicts: include/linux/perf_event.h kernel/rcutree.h kernel/rcutree_plugin.h Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2013-04-03nohz: Rename CONFIG_NO_HZ to CONFIG_NO_HZ_COMMONFrederic Weisbecker1-1/+1
We are planning to convert the dynticks Kconfig options layout into a choice menu. The user must be able to easily pick any of the following implementations: constant periodic tick, idle dynticks, full dynticks. As this implies a mutual exclusion, the two dynticks implementions need to converge on the selection of a common Kconfig option in order to ease the sharing of a common infrastructure. It would thus seem pretty natural to reuse CONFIG_NO_HZ to that end. It already implements all the idle dynticks code and the full dynticks depends on all that code for now. So ideally the choice menu would propose CONFIG_NO_HZ_IDLE and CONFIG_NO_HZ_EXTENDED then both would select CONFIG_NO_HZ. On the other hand we want to stay backward compatible: if CONFIG_NO_HZ is set in an older config file, we want to enable CONFIG_NO_HZ_IDLE by default. But we can't afford both at the same time or we run into a circular dependency: 1) CONFIG_NO_HZ_IDLE and CONFIG_NO_HZ_EXTENDED both select CONFIG_NO_HZ 2) If CONFIG_NO_HZ is set, we default to CONFIG_NO_HZ_IDLE We might be able to support that from Kconfig/Kbuild but it may not be wise to introduce such a confusing behaviour. So to solve this, create a new CONFIG_NO_HZ_COMMON option which gathers the common code between idle and full dynticks (that common code for now is simply the idle dynticks code) and select it from their referring Kconfig. Then we'll later create CONFIG_NO_HZ_IDLE and map CONFIG_NO_HZ to it for backward compatibility. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux.com> Cc: Geoff Levand <geoff@infradead.org> Cc: Gilad Ben Yossef <gilad@benyossef.com> Cc: Hakan Akkan <hakanakkan@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Kevin Hilman <khilman@linaro.org> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de>
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