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7de5f68d |
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28-May-2021 |
Eric W. Biederman <ebiederm@xmission.com> |
signal/alpha: si_trapno is only used with SIGFPE and SIGTRAP TRAP_UNK While reviewing the signal handlers on alpha it became clear that si_trapno is only set to a non-zero value when sending SIGFPE and when sending SITGRAP with si_code TRAP_UNK. Add send_sig_fault_trapno and send SIGTRAP TRAP_UNK, and SIGFPE with it. Remove the define of __ARCH_SI_TRAPNO and remove the always zero si_trapno parameter from send_sig_fault and force_sig_fault. v1: https://lkml.kernel.org/r/m1eeers7q7.fsf_-_@fess.ebiederm.org v2: https://lkml.kernel.org/r/20210505141101.11519-7-ebiederm@xmission.com Link: https://lkml.kernel.org/r/87h7gvxx7l.fsf_-_@disp2133 Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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f2838018 |
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18-Apr-2018 |
Eric W. Biederman <ebiederm@xmission.com> |
signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE Rework the defintion of struct siginfo so that the array padding struct siginfo to SI_MAX_SIZE can be placed in a union along side of the rest of the struct siginfo members. The result is that we no longer need the __ARCH_SI_PREAMBLE_SIZE or SI_PAD_SIZE definitions. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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535906c6 |
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17-Apr-2018 |
Eric W. Biederman <ebiederm@xmission.com> |
signal/alpha: Replace TRAP_FIXME with TRAP_UNK Using an si_code of 0 that aliases with SI_USER is clearly the wrong thing to do, and causes problems in interesting ways. For it really is not clear to me if using TRAP_UNK bugcheck or the default case of gentrap is really the best way to handle things. There is certainly enough information that that a more specific si_code could potentially be used. That said TRAP_UNK is definitely an improvement over 0 as it removes the ambiguiuty of what si_code of 0 with SIGTRAP means on alpha. Recent history suggests no actually cares about crazy corner cases of the kernel behavior like this so I don't expect any regressions from changing this. However if something does happen this change is easy to revert. Cc: Helge Deller <deller@gmx.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: linux-alpha@vger.kernel.org Fixes: 0a635c7a84cf ("Fill in siginfo_t.") History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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4cc13e4f |
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17-Apr-2018 |
Eric W. Biederman <ebiederm@xmission.com> |
signal/alpha: Replace FPE_FIXME with FPE_FLTUNK Using an si_code of 0 that aliases with SI_USER is clearly the wrong thing todo, and causes problems in interesting ways. The newly defined FPE_FLTUNK semantically appears to fit the bill so use it instead. Given recent experience in this area odds are it will not break anything. Fixing it removes a hazard to kernel maintenance. Cc: Helge Deller <deller@gmx.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: linux-alpha@vger.kernel.org History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Fixes: 0a635c7a84cf ("Fill in siginfo_t.") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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6f52b16c |
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01-Nov-2017 |
Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
License cleanup: add SPDX license identifier to uapi header files with no license Many user space API headers are missing licensing information, which makes it hard for compliance tools to determine the correct license. By default are files without license information under the default license of the kernel, which is GPLV2. Marking them GPLV2 would exclude them from being included in non GPLV2 code, which is obviously not intended. The user space API headers fall under the syscall exception which is in the kernels COPYING file: NOTE! This copyright does *not* cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does *not* fall under the heading of "derived work". otherwise syscall usage would not be possible. Update the files which contain no license information with an SPDX license identifier. The chosen identifier is 'GPL-2.0 WITH Linux-syscall-note' which is the officially assigned identifier for the Linux syscall exception. SPDX license identifiers are 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. See the previous patch in this series for the methodology of how this patch was researched. 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>
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cc731525 |
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16-Jul-2017 |
Eric W. Biederman <ebiederm@xmission.com> |
signal: Remove kernel interal si_code magic struct siginfo is a union and the kernel since 2.4 has been hiding a union tag in the high 16bits of si_code using the values: __SI_KILL __SI_TIMER __SI_POLL __SI_FAULT __SI_CHLD __SI_RT __SI_MESGQ __SI_SYS While this looks plausible on the surface, in practice this situation has not worked well. - Injected positive signals are not copied to user space properly unless they have these magic high bits set. - Injected positive signals are not reported properly by signalfd unless they have these magic high bits set. - These kernel internal values leaked to userspace via ptrace_peek_siginfo - It was possible to inject these kernel internal values and cause the the kernel to misbehave. - Kernel developers got confused and expected these kernel internal values in userspace in kernel self tests. - Kernel developers got confused and set si_code to __SI_FAULT which is SI_USER in userspace which causes userspace to think an ordinary user sent the signal and that it was not kernel generated. - The values make it impossible to reorganize the code to transform siginfo_copy_to_user into a plain copy_to_user. As si_code must be massaged before being passed to userspace. So remove these kernel internal si codes and make the kernel code simpler and more maintainable. To replace these kernel internal magic si_codes introduce the helper function siginfo_layout, that takes a signal number and an si_code and computes which union member of siginfo is being used. Have siginfo_layout return an enumeration so that gcc will have enough information to warn if a switch statement does not handle all of union members. A couple of architectures have a messed up ABI that defines signal specific duplications of SI_USER which causes more special cases in siginfo_layout than I would like. The good news is only problem architectures pay the cost. Update all of the code that used the previous magic __SI_ values to use the new SIL_ values and to call siginfo_layout to get those values. Escept where not all of the cases are handled remove the defaults in the switch statements so that if a new case is missed in the future the lack will show up at compile time. Modify the code that copies siginfo si_code to userspace to just copy the value and not cast si_code to a short first. The high bits are no longer used to hold a magic union member. Fixup the siginfo header files to stop including the __SI_ values in their constants and for the headers that were missing it to properly update the number of si_codes for each signal type. The fixes to copy_siginfo_from_user32 implementations has the interesting property that several of them perviously should never have worked as the __SI_ values they depended up where kernel internal. With that dependency gone those implementations should work much better. The idea of not passing the __SI_ values out to userspace and then not reinserting them has been tested with criu and criu worked without changes. Ref: 2.4.0-test1 Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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e2bd64d9 |
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26-Jun-2017 |
Eric W. Biederman <ebiederm@xmission.com> |
signal/alpha: Document a conflict with SI_USER for SIGTRAP Setting si_code to __SI_FAULT results in a userspace seeing an si_code of 0. This is the same si_code as SI_USER. Posix and common sense requires that SI_USER not be a signal specific si_code. As such this use of 0 for the si_code is a pretty horribly broken ABI. Given that alpha is on it's last legs I don't know that it is worth fixing this, but it is worth documenting what is going on so that no one decides to copy this bad decision. This was introduced during the 2.5 development cycle so this mess has had a long time for people to be able to depend upon it. v2: Added FPE_FIXME for alpha as Helge Deller <deller@gmx.de> pointed out with his alternate patch one of the cases is SIGFPE not SIGTRAP. Cc: Helge Deller <deller@gmx.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> Cc: linux-alpha@vger.kernel.org Acked-by: Richard Henderson <rth@twiddle.net> History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git Ref: 0a635c7a84cf ("Fill in siginfo_t.") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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96433f6e |
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17-Dec-2012 |
David Howells <dhowells@redhat.com> |
UAPI: (Scripted) Disintegrate arch/alpha/include/asm Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michael Kerrisk <mtk.manpages@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Dave Jones <davej@redhat.com> Acked-by: Michael Cree <mcree@orcon.net.nz> Acked-by: Matt Turner <mattst88@gmail.com>
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