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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>
2013-03-11um: fix build failure due to mess-up of sig_info protorypeSergei Trofimovich1-1/+1
arch/um/os-Linux/signal.c:18:8: error: conflicting types for 'sig_info' In file included from /home/slyfox/linux-2.6/arch/um/os-Linux/signal.c:12:0: arch/um/include/shared/as-layout.h:64:15: note: previous declaration of 'sig_info' was here Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> CC: Jeff Dike <jdike@addtoit.com> CC: Richard Weinberger <richard@nod.at> CC: "Martin Pärtel" <martin.partel@gmail.com> CC: Al Viro <viro@zeniv.linux.org.uk> CC: user-mode-linux-devel@lists.sourceforge.net CC: user-mode-linux-user@lists.sourceforge.net CC: linux-kernel@vger.kernel.org Signed-off-by: Richard Weinberger <richard@nod.at>
2013-03-11um: add missing declaration of 'getrlimit()' and friendsSergei Trofimovich1-0/+2
arch/um/os-Linux/start_up.c: In function 'check_coredump_limit': arch/um/os-Linux/start_up.c:338:16: error: storage size of 'lim' isn't known arch/um/os-Linux/start_up.c:339:2: error: implicit declaration of function 'getrlimit' [-Werror=implicit-function-declaration] Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> CC: Jeff Dike <jdike@addtoit.com> CC: Richard Weinberger <richard@nod.at> CC: Al Viro <viro@zeniv.linux.org.uk> CC: user-mode-linux-devel@lists.sourceforge.net CC: user-mode-linux-user@lists.sourceforge.net CC: linux-kernel@vger.kernel.org Signed-off-by: Richard Weinberger <richard@nod.at>
2012-10-13Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signalLinus Torvalds1-13/+0
Pull third pile of kernel_execve() patches from Al Viro: "The last bits of infrastructure for kernel_thread() et.al., with alpha/arm/x86 use of those. Plus sanitizing the asm glue and do_notify_resume() on alpha, fixing the "disabled irq while running task_work stuff" breakage there. At that point the rest of kernel_thread/kernel_execve/sys_execve work can be done independently for different architectures. The only pending bits that do depend on having all architectures converted are restrictred to fs/* and kernel/* - that'll obviously have to wait for the next cycle. I thought we'd have to wait for all of them done before we start eliminating the longjump-style insanity in kernel_execve(), but it turned out there's a very simple way to do that without flagday-style changes." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal: alpha: switch to saner kernel_execve() semantics arm: switch to saner kernel_execve() semantics x86, um: convert to saner kernel_execve() semantics infrastructure for saner ret_from_kernel_thread semantics make sure that kernel_thread() callbacks call do_exit() themselves make sure that we always have a return path from kernel_execve() ppc: eeh_event should just use kthread_run() don't bother with kernel_thread/kernel_execve for launching linuxrc alpha: get rid of switch_stack argument of do_work_pending() alpha: don't bother passing switch_stack separately from regs alpha: take SIGPENDING/NOTIFY_RESUME loop into signal.c alpha: simplify TIF_NEED_RESCHED handling
2012-10-12x86, um: convert to saner kernel_execve() semanticsAl Viro1-13/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-10-09um: get rid of pointless include "..." where include <...> will doAl Viro26-85/+85
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2012-09-05uml: fix compile error in deliver_alarm()Miklos Szeredi1-1/+1
Fix the following compile error on UML. arch/um/os-Linux/time.c: In function 'deliver_alarm': arch/um/os-Linux/time.c:117:3: error: too few arguments to function 'alarm_handler' arch/um/os-Linux/internal.h:1:6: note: declared here The error was introduced by commit d3c1cfcd ("um: pass siginfo to guest process") in 3.6-rc1. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> CC: Martin Pärtel <martin.partel@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-08-02um: pass siginfo to guest processMartin Pärtel4-17/+26
UML guest processes now get correct siginfo_t for SIGTRAP, SIGFPE, SIGILL and SIGBUS. Specifically, si_addr and si_code are now correct where previously they were si_addr = NULL and si_code = 128. Signed-off-by: Martin Pärtel <martin.partel@gmail.com> Signed-off-by: Richard Weinberger <richard@nod.at>
2012-08-02um: pull interrupt_end() into userspace()Al Viro1-0/+3
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2012-05-21um: Remove unused variablesRichard Weinberger1-10/+0
Signed-off-by: Richard Weinberger <richard@nod.at>
2012-03-25um: use the right ifdef around exports in user_syms.cAl Viro2-3/+1
... the same one that controls whether elf_aux.o is included into the build, bringing the vsyscall_e... into it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: unify ptrace_user.hAl Viro2-7/+5
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: merge os-Linux/tls.c into arch/x86/um/os-Linux/tls.cAl Viro2-37/+2
it's i386-specific; moreover, analogs on other targets have incompatible interface - PTRACE_GET_THREAD_AREA does exist elsewhere, but struct user_desc does *not* Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: take chan_*.h and line.h to arch/um/driversAl Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: take register_winch_irq() into the caller of is_skas_winch()Al Viro1-5/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: take arch/um/sys-x86 to arch/x86/umAl Viro7-353/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: sysdep/barrier.h is not used for anythingAl Viro1-1/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: shared/process.h is empty now; kill itAl Viro5-5/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: finish conversion to mcontext_tAl Viro3-4/+35
now we don't mix host and guest signal frame layouts anymore; moreover, we don't need host's struct sigcontext at all. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: start switching the references to host mcontext_t to its userland typeAl Viro3-20/+18
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: take userland definition of barrier() to user.hAl Viro1-3/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: fill the handlers array at build timeAl Viro3-11/+20
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: simplify set_handler()Al Viro3-26/+18
For one thing, we always block the same signals (IRQ ones - IO, WINCH, VTALRM), so there's no need to pass sa_mask elements in arguments. For another, the flags depend only on whether it's an IRQ signal or not (we add SA_RESTART for them). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: don't bother blocking SIGARLM and SIGUSR1Al Viro3-9/+8
We used to generate those, but we hadn't done that for a long time. No need to bother blocking them for signal handlers. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: switch stub_segv_handler to SA_SIGINFO variant, get rid of magic crap in thereAl Viro1-2/+2
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: merge arch/um/os-Linux/sys-{i386,x86_64}Al Viro9-85/+57
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: merge hard_handler() instances, switch to use of SA_SIGINFOAl Viro5-35/+10
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: kill dead code around uaccessAl Viro2-34/+2
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: -include user.h for USER_OBJ, trim includesAl Viro23-40/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2011-09-14um: Save FPU registers between task switchesIngo van Lil3-3/+27
Some time ago Jeff prepared 42daba316557 ("uml: stop saving process FP state") for UML to stop saving the process FP state between task switches. The assumption was that since with SKAS0 every guest process runs inside a host process context the host OS will take care of keeping the proper FP state. Unfortunately this is not true for multi-threaded applications, where all guest threads share a single host process context yet all may use the FPU on their own. Although I haven't verified it I suspect things to be even worse in SKAS3 mode where all guest processes run inside a single host process. The patch reintroduces the saving and restoring of the FP context between task switches. [richard@nod.at: Ingo posted this patch in 2009, sadly it was never applied and got lost. Now in 2011 the problem was reported by Gunnar.] Signed-off-by: Ingo van Lil <inguin@gmx.de> Signed-off-by: Richard Weinberger <richard@nod.at> Reported-by: <gunnarlindroth@hotmail.com> Tested-by: <gunnarlindroth@hotmail.com> Cc: Stanislav Meduna <stano@meduna.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25um: disable scan_elf_aux() on x86_64Richard Weinberger3-7/+8
Reusing the host's vDSO makes only sense on x86_32. Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25uml: free resourcesDavidlohr Bueso1-2/+4
When creating the temp file there's a memory and file descriptor leak upon error. Signed-off-by: Davidlohr Bueso <dave@gnu.org> Signed-off-by: Richard Weinberger <richard@nod.at> Reviewed-by: Vitaliy Ivanov <vitalivanov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25uml: helper.c warning correctionsVitaliy Ivanov1-2/+2
Fix this warning: arch/um/os-Linux/helper.c: In function `helper_child': arch/um/os-Linux/helper.c:38:7: warning: ignoring return value of `write', declared with attribute warn_unused_result [richard@nod.at: happens only with -D_FORTIFY_SOURCE=2] Signed-off-by: Vitaliy Ivanov <vitalivanov@gmail.com> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25um: fix _FORTIFY_SOURCE=2 support for kernel modulesRichard Weinberger1-0/+5
When UML is compiled with _FORTIFY_SOURCE we have to export all _chk() functions which are used in modules. For now it's only the case for __sprintf_chk(). Tested-by: Florian Fainelli <florian@openwrt.org> Reported-by: Florian Fainelli <florian@openwrt.org> Signed-off-by: Richard Weinberger <richard@nod.at> Acked-by: Vitaliy Ivanov <vitalivanov@gmail.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25um: fix crash while os_dump_core()Richard Weinberger1-0/+1
os_dump_core() emits SIGTERM to terminate all UML processes. Kernel threads have to exit on SIGTERM instead of calling last_ditch_exit(). Multiple calls to last_ditch_exit() can cause a crash. Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25um: add earlyprintk supportRichard Weinberger1-0/+5
User Mode Linux can also benefit from earlyprintk. UML's earlyprintk writes kernel messages directly to stdout. Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25um: remove SIGHUP handlerRichard Weinberger1-1/+0
The UML kernel ignores SIGHUP anyway. This handler is in vain. Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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