On Thu, Jan 19, 2023 at 04:09:44PM -0700, Jens Axboe wrote: > On 1/19/23 2:03?PM, Salvatore Bonaccorso wrote: > > Hi Luis, all, > > > > On Thu, Jan 19, 2023 at 10:16:34AM -0300, Luis Claudio R. Goncalves wrote: > >> On Thu, Jan 19, 2023 at 12:38:25PM +0100, Pavel Machek wrote: > >>> Hi! > >>> > >>>>> I'm pleased to announce the 5.10.162-rt78 stable release. > >>>>> > >>>>> You can get this release via the git tree at: > >>>>> > >>>>> git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git > >>>>> > >>>>> branch: v5.10-rt > >>>>> Head SHA1: 143ef105f40a65f3ddd57121d4b4bc36eb10cc06 > >>>>> > >>>>> Or to build 5.10.162-rt78 directly, the following patches should be applied: > >>> > >>>> I see that vanilla 5.10.162-rt78 fails to build with arm64 defconfig. [0] Full log [1] > >>>> Any pointers on what maybe wrong? > >>> > >>> We see the same failure. > >>> > >>>> AS arch/arm64/kernel/entry.o > >>>> arch/arm64/kernel/entry.S: Assembler messages: > >>>> arch/arm64/kernel/entry.S:763: Error: immediate out of range at operand 3 -- `and x2,x19,#((1<<1)|(1<<0)|(1<<2)|(1<<3)|(1<<4)|(1<<5)|(1<<6)|(1<<13)|(1<<7))' > >>>> make[2]: *** [scripts/Makefile.build:367: arch/arm64/kernel/entry.o] Error 1 > >>>> make[1]: *** [scripts/Makefile.build:503: arch/arm64/kernel] Error 2 > >>>> make: *** [Makefile:1837: arch/arm64] Error 2 > >>> > >>> The line is: > >>> > >>>> and x2, x19, #_TIF_WORK_MASK > >> > >> I believe this is related to the arch/arm64/include/asm/thread_info.h > >> changes in 5.10.162-rt78, specifically: > >> > >> 79a9991e87fe arm64: add support for TIF_NOTIFY_SIGNAL > >> 1ba44dcf789d Merge tag 'v5.10.162' into v5.10-rt > >> > >> The first one is the original change, coming from stable v5.10.162 and the > >> second one has the merge conflict I fixed in that file due to the existence > >> of TIF_NEED_RESCHED_LAZY in PREEMPT_RT. > >> > >> It escaped me that having TIF_NEED_RESCHED_LAZY set to 13 breaks the AND > >> statement reported above. Looking at > >> > >> b5a5a01d8e9a arm64: uaccess: remove addr_limit_user_check() > >> > >> specially this note > >> > >> To ensure that _TIF_WORK_MASK can be used as an immediate value in an > >> AND instruction (as it is in `ret_to_user`), TIF_MTE_ASYNC_FAULT is > >> renumbered to keep the constituent bits of _TIF_WORK_MASK contiguous. > >> > >> I understand that I need to either have to renumber TIF_NEED_RESCHED_LAZY > >> to 8, with the risk of breaking something else, or backport commit > >> b5a5a01d8e9a in order to remove TIF_FSCHECK and then safely renumber > >> TIF_NEED_RESCHED_LAZY. > >> > >> Guidance is welcome here :) > > > > Should we loop in here Jens, as having some overview of the needed > > changes for io_uring rebase in the 5.10.y version? (doing so in the > > mail). > > Huh that's funky, I built and (runtime) tested this on arm64 > specifically. But I do remember some details about the first 8 bits on > arm, but not arm64. > > I guess we need to twiddle that asm to deal with eg 16 bits, rather than > attempt to backport any TIF removal patches. One simple solution, tested with defconfig plus FTRACE options (including FTRACE_SYSCALLS) enabled, is: diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index 6eb36a2126e8..37f19bb49d38 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -70,12 +70,12 @@ void arch_release_task_struct(struct task_struct *tsk); #define TIF_FSCHECK 5 /* Check FS is USER_DS on return */ #define TIF_MTE_ASYNC_FAULT 6 /* MTE Asynchronous Tag Check Fault */ #define TIF_NOTIFY_SIGNAL 7 /* signal notifications exist */ -#define TIF_SYSCALL_TRACE 8 /* syscall trace active */ +#define TIF_NEED_RESCHED_LAZY 8 #define TIF_SYSCALL_AUDIT 9 /* syscall auditing */ #define TIF_SYSCALL_TRACEPOINT 10 /* syscall tracepoint for ftrace */ #define TIF_SECCOMP 11 /* syscall secure computing */ #define TIF_SYSCALL_EMU 12 /* syscall emulation active */ -#define TIF_NEED_RESCHED_LAZY 13 +#define TIF_SYSCALL_TRACE 13 /* syscall trace active */ #define TIF_MEMDIE 18 /* is terminating due to OOM killer */ #define TIF_FREEZE 19 #define TIF_RESTORE_SIGMASK 20 Would that be acceptable? With that we ensure the bits in _TIF_WORK_MASK are contiguous and within the 8 bits limit you mentioned. And TIF_SYSCALL_TRACE did not seem to have any (build) problem with the new value. Luis > > -- > Jens Axboe > ---end quoted text---
