On 2025-11-03 11:08:35 [+0100], Michal Pecio wrote: > Hi, Hi, > There is a regression report on a distribution forum which involves > an out of tree module on a patched kernel (yes, I know) calling > stack_trace_save() in task context, which arrives here and apparently > calls the various deref_stack_xxx() functions with preemption enabled, > which in turn call stack_access_ok() leading to a BUG: > > Nov 02 21:44:30 ArchBasement kernel: BUG: using smp_processor_id() in > preemptible [00000000] code: Xorg/1183 > Nov 02 21:44:30 ArchBasement kernel: caller is in_entry_stack+0x11/0x60 > Nov 02 21:44:30 ArchBasement kernel: CPU: 0 UID: 1000 PID: 1183 Comm: Xorg > Tainted: P OE 6.16.12-hardened1-1-hardened #1 PREEMPT(full) > 6edb90a7a07fab33bbee72d6d5ef53ba6eec3b9c > Nov 02 21:44:30 ArchBasement kernel: Tainted: [P]=PROPRIETARY_MODULE, > [O]=OOT_MODULE, [E]=UNSIGNED_MODULE > Nov 02 21:44:30 ArchBasement kernel: Hardware name: ASUS All Series/Z97-E, > BIOS 0803 02/23/2016 > Nov 02 21:44:30 ArchBasement kernel: Call Trace: > Nov 02 21:44:30 ArchBasement kernel: <TASK> > Nov 02 21:44:30 ArchBasement kernel: dump_stack_lvl+0x5d/0x80 > Nov 02 21:44:30 ArchBasement kernel: check_preemption_disabled+0xe5/0xf0 > Nov 02 21:44:30 ArchBasement kernel: in_entry_stack+0x11/0x60 > Nov 02 21:44:30 ArchBasement kernel: get_stack_info+0x2c/0x80 > Nov 02 21:44:30 ArchBasement kernel: stack_access_ok+0x51/0xa0 > Nov 02 21:44:30 ArchBasement kernel: unwind_next_frame+0x1cb/0x7b0 > Nov 02 21:44:30 ArchBasement kernel: ? _nv003168kms+0x42/0x50 > [nvidia_modeset 90775ea8a26c5e58b97ef4b3f46eb45efa040eb2] > Nov 02 21:44:30 ArchBasement kernel: ? > __pfx_stack_trace_consume_entry+0x10/0x10 > Nov 02 21:44:30 ArchBasement kernel: arch_stack_walk+0xa6/0x110 > Nov 02 21:44:30 ArchBasement kernel: ? _nv003168kms+0x42/0x50 > [nvidia_modeset 90775ea8a26c5e58b97ef4b3f46eb45efa040eb2] > Nov 02 21:44:30 ArchBasement kernel: stack_trace_save+0x4d/0x70 > > Is this nvidia doing something wrong, or a problem with this commit? > > The removed code suggests that preemption is allowed here, and as far > as I see, this call trace is still possible on vanilla 6.18. Perhaps > preempt_disable() needs to be restored around this code?
Do you have the complete backtrace? Is this SMP or UP build? > Regards, > Michal Sebastian
