linux/kernel/signal.c, branch v6.7

Merge tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2023-11-03T06:53:31Z

Pull non-MM updates from Andrew Morton: "As usual, lots of singleton and doubleton patches all over the tree and there's little I can say which isn't in the individual changelogs. The lengthier patch series are - 'kdump: use generic functions to simplify crashkernel reservation in arch', from Baoquan He. This is mainly cleanups and consolidation of the 'crashkernel=' kernel parameter handling - After much discussion, David Laight's 'minmax: Relax type checks in min() and max()' is here. Hopefully reduces some typecasting and the use of min_t() and max_t() - A group of patches from Oleg Nesterov which clean up and slightly fix our handling of reads from /proc/PID/task/... and which remove task_struct.thread_group" * tag 'mm-nonmm-stable-2023-11-02-14-08' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (64 commits) scripts/gdb/vmalloc: disable on no-MMU scripts/gdb: fix usage of MOD_TEXT not defined when CONFIG_MODULES=n .mailmap: add address mapping for Tomeu Vizoso mailmap: update email address for Claudiu Beznea tools/testing/selftests/mm/run_vmtests.sh: lower the ptrace permissions .mailmap: map Benjamin Poirier's address scripts/gdb: add lx_current support for riscv ocfs2: fix a spelling typo in comment proc: test ProtectionKey in proc-empty-vm test proc: fix proc-empty-vm test with vsyscall fs/proc/base.c: remove unneeded semicolon do_io_accounting: use sig->stats_lock do_io_accounting: use __for_each_thread() ocfs2: replace BUG_ON() at ocfs2_num_free_extents() with ocfs2_error() ocfs2: fix a typo in a comment scripts/show_delta: add __main__ judgement before main code treewide: mark stuff as __ro_after_init fs: ocfs2: check status values proc: test /proc/${pid}/statm compiler.h: move __is_constexpr() to compiler.h ...

Merge tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2023-11-02T01:28:33Z

Pull ia64 removal and asm-generic updates from Arnd Bergmann: - The ia64 architecture gets its well-earned retirement as planned, now that there is one last (mostly) working release that will be maintained as an LTS kernel. - The architecture specific system call tables are updated for the added map_shadow_stack() syscall and to remove references to the long-gone sys_lookup_dcookie() syscall. * tag 'asm-generic-6.7' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: hexagon: Remove unusable symbols from the ptrace.h uapi asm-generic: Fix spelling of architecture arch: Reserve map_shadow_stack() syscall number for all architectures syscalls: Cleanup references to sys_lookup_dcookie() Documentation: Drop or replace remaining mentions of IA64 lib/raid6: Drop IA64 support Documentation: Drop IA64 from feature descriptions kernel: Drop IA64 support from sig_fault handlers arch: Remove Itanium (IA-64) architecture

kernel/signal: remove unnecessary NULL values from ucounts

2023-10-18T21:43:22Z

ucounts is assigned first, so it does not need to initialize the assignment. Link: https://lkml.kernel.org/r/20230926022410.4280-1-kunyu@nfschina.com Signed-off-by: Li kunyu Acked-by: Oleg Nesterov Signed-off-by: Andrew Morton

signal: complete_signal: use __for_each_thread()

2023-10-04T17:41:57Z

do/while_each_thread should be avoided when possible. Link: https://lkml.kernel.org/r/20230909164537.GA11633@redhat.com Signed-off-by: Oleg Nesterov Cc: Eric W. Biederman Signed-off-by: Andrew Morton

__kill_pgrp_info: simplify the calculation of return value

2023-10-04T17:41:56Z

No need to calculate/check the "success" variable, we can kill it and update retval in the main loop unless it is zero. Link: https://lkml.kernel.org/r/20230823171455.GA12188@redhat.com Signed-off-by: Oleg Nesterov Suggested-by: David Laight Cc: Eric W. Biederman Signed-off-by: Andrew Morton

signal: Don't disable preemption in ptrace_stop() on PREEMPT_RT

2023-09-19T20:08:29Z

On PREEMPT_RT keeping preemption disabled during the invocation of cgroup_enter_frozen() is a problem because the function acquires css_set_lock which is a sleeping lock on PREEMPT_RT and must not be acquired with disabled preemption. The preempt-disabled section is only for performance optimisation reasons and can be avoided. Extend the comment and don't disable preemption before scheduling on PREEMPT_RT. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Acked-by: Oleg Nesterov Link: https://lore.kernel.org/r/20230803100932.325870-3-bigeasy@linutronix.de

signal: Add a proper comment about preempt_disable() in ptrace_stop()

2023-09-19T20:08:29Z

Commit 53da1d9456fe7 ("fix ptrace slowness") added a preempt-disable section between read_unlock() and the following schedule() invocation without explaining why it is needed. Replace the existing contentless comment with a proper explanation to clarify that it is not needed for correctness but for performance reasons. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Acked-by: Oleg Nesterov Link: https://lore.kernel.org/r/20230803100932.325870-2-bigeasy@linutronix.de

kernel: Drop IA64 support from sig_fault handlers

2023-09-11T08:13:18Z

Signed-off-by: Ard Biesheuvel

signal: print comm and exe name on fatal signals

2023-08-18T17:18:50Z

Make the print-fatal-signals message more useful by printing the comm and the exe name for the process which received the fatal signal: Before: potentially unexpected fatal signal 4 potentially unexpected fatal signal 11 After: buggy-program: pool: potentially unexpected fatal signal 4 some-daemon: gdbus: potentially unexpected fatal signal 11 comm used to be present but was removed in commit 681a90ffe829b8ee25d ("arc, print-fatal-signals: reduce duplicated information") because it's also included as part of the later stack trace. Having the comm as part of the main "unexpected fatal..." print is rather useful though when analysing logs, and the exe name is also valuable as shown in the examples above where the comm ends up having some generic name like "pool". [akpm@linux-foundation.org: don't include linux/file.h twice] Link: https://lkml.kernel.org/r/20230707-fatal-comm-v1-1-400363905d5e@axis.com Signed-off-by: Vincent Whitchurch Cc: Ingo Molnar Cc: Tejun Heo Cc: Vineet Gupta Signed-off-by: Andrew Morton

mm: suppress mm fault logging if fatal signal already pending

2023-07-26T17:51:59Z

Commit eda0047296a1 ("mm: make the page fault mmap locking killable") intentionally made it much easier to trigger the "page fault fails because a fatal signal is pending" situation, by having the mmap locking fail early in that case. We have long aborted page faults in other fatal cases when the actual IO for a page is interrupted by SIGKILL - which is particularly useful for the traditional case of NFS hanging due to network issues, but local filesystems could cause it too if you happened to get the SIGKILL while waiting for a page to be faulted in (eg lock_folio_maybe_drop_mmap()). So aborting the page fault wasn't a new condition - but it now triggers earlier, before we even get to 'handle_mm_fault()'. And as a result the error doesn't go through our 'fault_signal_pending()' logic, and doesn't get filtered away there. Normally you'd never even notice, because if a fatal signal is pending, the new SIGSEGV we send ends up being ignored anyway. But it turns out that there is one very noticeable exception: if you enable 'show_unhandled_signals', the aborted page fault will be logged in the kernel messages, and you'll get a scary line looking something like this in your logs: pverados[2183248]: segfault at 55e5a00f9ae0 ip 000055e5a00f9ae0 sp 00007ffc0720bea8 error 14 in perl[55e5a00d4000+195000] likely on CPU 10 (core 4, socket 0) which is rather misleading. It's not really a segfault at all, it's just "the thread was killed before the page fault completed, so we aborted the page fault". Fix this by just making it clear that a pending fatal signal means that any new signal coming in after that is implicitly handled. This will avoid the misleading logging, since now the signal isn't 'unhandled' any more. Reported-and-tested-by: Fiona Ebner Tested-by: Thomas Lamprecht Link: https://lore.kernel.org/lkml/8d063a26-43f5-0bb7-3203-c6a04dc159f8@proxmox.com/ Acked-by: Oleg Nesterov Fixes: eda0047296a1 ("mm: make the page fault mmap locking killable") Signed-off-by: Linus Torvalds