Re: powerpc: userspace processes crash on abort() from libc.so.6
From: Shivaprasad G Bhat <hidden>
Date: 2026-08-27 14:16:40
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Hi Shrikanth, On 8/27/26 5:08 PM, Shrikanth Hegde wrote:
quoted hunk ↗ jump to hunk
Hi Shivaprasad. On 8/27/26 11:13 AM, Shivaprasad G Bhat wrote:quoted
Hi All, Thomas, On my PPC64 machine, I see the below systemd crash orginating from abort() during boot on top of the tree. Complete dmesg can be seen here [1] abort (libc.so.6 + 0x29484) __libc_message_impl (libc.so.6 + 0x9e00c) __libc_fatal (libc.so.6 + 0x9e06c) start_thread (libc.so.6 + 0xadffc) __clone (libc.so.6 + 0x152d68) __clone (libc.so.6 + 0x152d68) create_thread.constprop.0 (libc.so.6 + 0xad9c8) The git bisect pointed me to commit 3424d8c18a7da "(Merge tag 'core- entry-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/ tip/tip)" Please find the kernel config used to build the kernel at [2]. I have tried applying the pending fixes from Mukesh [3] and Ritesh [4] for the currently outstanding issues and still see the problem. The system is running Fedora 42, with glibc-2.41-7.fc42.ppc64le. The complete list of toolchain and packages can be found here [5] Thanks and Regards, Shivaprasad References: 1 - https://gist.github.com/ shivaprasadbhat/6f166374bab12b4f4c1cd4ac829e562c 2 - https://gist.github.com/shivaprasadbhat/ aa499468e124015eec5932fb13e88e05 3 - https://lore.kernel.org/linuxppc-dev/ lda1jyut.ritesh.list@gmail.com/#t 4 - https://lore.kernel.org/linuxppc-dev/20260820134718.2176411-1- mkchauras@gmail.com/ 5 - https://gist.github.com/shivaprasadbhat/ ae56ca849c3009e8642a6313dc465ea7 ========= Backtrace from dmesg: [ 22.039343][ T1833] systemd-coredump[1833]: Module libsystemd- shared-257.6-1.fc42.so from rpm systemd-257.6-1.fc42.ppc64le [ 22.039378][ T1833] systemd-coredump[1833]: Stack trace of thread 1828: [ 22.039378][ T1833] systemd-coredump[1833]: Stack trace of thread 1828: [ 22.039401][ T1833] systemd-coredump[1833]: #0 0x00007fffa4c29484 abort (libc.so.6 + 0x29484) [ 22.039401][ T1833] systemd-coredump[1833]: #0 0x00007fffa4c29484 abort (libc.so.6 + 0x29484) [ 22.039429][ T1833] systemd-coredump[1833]: #1 0x00007fffa4c9e00c __libc_message_impl (libc.so.6 + 0x9e00c) [ 22.039429][ T1833] systemd-coredump[1833]: #1 0x00007fffa4c9e00c __libc_message_impl (libc.so.6 + 0x9e00c) [ 22.039461][ T1833] systemd-coredump[1833]: #2 0x00007fffa4c9e06c __libc_fatal (libc.so.6 + 0x9e06c) [ 22.039461][ T1833] systemd-coredump[1833]: #2 0x00007fffa4c9e06c __libc_fatal (libc.so.6 + 0x9e06c) [ 22.039491][ T1833] systemd-coredump[1833]: #3 0x00007fffa4cadffc start_thread (libc.so.6 + 0xadffc) [ 22.039491][ T1833] systemd-coredump[1833]: #3 0x00007fffa4cadffc start_thread (libc.so.6 + 0xadffc) [ 22.039521][ T1833] systemd-coredump[1833]: #4 0x00007fffa4d52d68 __clone (libc.so.6 + 0x152d68) [ 22.039521][ T1833] systemd-coredump[1833]: #4 0x00007fffa4d52d68 __clone (libc.so.6 + 0x152d68) [ 22.039551][ T1833] systemd-coredump[1833]: #5 0x00007fffa4d52d68 __clone (libc.so.6 + 0x152d68) [ 22.039551][ T1833] systemd-coredump[1833]: #5 0x00007fffa4d52d68 __clone (libc.so.6 + 0x152d68) [ 22.039580][ T1833] systemd-coredump[1833]: #6 0x00007fffa4cad9c8 create_thread.constprop.0 (libc.so.6 + 0xad9c8) [ 22.039580][ T1833] systemd-coredump[1833]: #6 0x00007fffa4cad9c8 create_thread.constprop.0 (libc.so.6 + 0xad9c8) [ 22.039614][ T1833] systemd-coredump[1833]: #7 0x00000000003af858 n/a (n/a + 0x0) [ 22.039614][ T1833] systemd-coredump[1833]: #7 0x00000000003af858 n/a (n/a + 0x0) [ 22.039639][ T1833] systemd-coredump[1833]: ELF object binary architecture: PowerPC64 [ 22.039639][ T1833] systemd-coredump[1833]: ELF object binary architecture: PowerPC64 [ 22.042109][ T1] systemd[1]: systemd-journald.service: Scheduled restart job, restart counter is at 1.I was looking at merge patch and It is possible that TIF_SYSCALL_RET is still set when it is returned and maybe causing a mismatch. Does below help? ------ a/arch/powerpc/kernel/syscall.c +++ b/arch/powerpc/kernel/syscall.c@@ -19,8 +19,10 @@ notrace long system_call_exception(struct pt_regs*regs, unsigned long r0) long ret; syscall_fn f; - if (unlikely(!syscall_enter_from_user_mode_randomize_stack(regs, &r0))) + if (unlikely(!syscall_enter_from_user_mode_randomize_stack(regs, &r0))) { + clear_thread_flag(TIF_SYSCALL_RET);
Yes. This worked. Thanks, Shivaprasad> return syscall_get_error(current, regs);
+ } if (unlikely(test_and_clear_thread_flag(TIF_SYSCALL_RET))) return syscall_get_error(current, regs);