diff options
| author | Christian Lamparter <chunkeey@gmail.com> | 2025-05-09 11:50:39 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-05-18 08:24:57 +0200 |
| commit | 6aac2c54762c4b0b1cbd8c7ffa365283e171bf5d (patch) | |
| tree | 841b3f9afe782a32a1fa14af1e181901cba89108 | |
| parent | cd010271a92b9c5e04901cdf630b0b92d25c3375 (diff) | |
Revert "um: work around sched_yield not yielding in time-travel mode"
This reverts commit da780c4a075ba2deb05ae29f0af4a990578c7901 which is
commit 887c5c12e80c8424bd471122d2e8b6b462e12874 upstream.
Reason being that the patch depends on at least commit 0b8b2668f998
("um: insert scheduler ticks when userspace does not yield") in order to
build. Otherwise it fails with:
| /usr/bin/ld: arch/um/kernel/skas/syscall.o: in function `handle_syscall':
| linux-6.12.27/arch/um/kernel/skas/syscall.c:43:(.text+0xa2): undefined
| reference to `tt_extra_sched_jiffies'
| collect2: error: ld returned 1 exit status
The author Benjamin Berg commented: "I think it is better to just not
backport commit 0b8b2668f998 ("um: insert scheduler ticks when userspace
does not yield")"
Link: https://lore.kernel.org/linux-um/8ce0b6056a9726e540f61bce77311278654219eb.camel@sipsolutions.net/
Cc: <stable@vger.kernel.org> # 6.12.y
Cc: Benjamin Berg <benjamin.berg@intel.com>
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/um/include/linux/time-internal.h | 2 | ||||
| -rw-r--r-- | arch/um/kernel/skas/syscall.c | 11 |
2 files changed, 0 insertions, 13 deletions
diff --git a/arch/um/include/linux/time-internal.h b/arch/um/include/linux/time-internal.h index 138908b999d7..b22226634ff6 100644 --- a/arch/um/include/linux/time-internal.h +++ b/arch/um/include/linux/time-internal.h @@ -83,8 +83,6 @@ extern void time_travel_not_configured(void); #define time_travel_del_event(...) time_travel_not_configured() #endif /* CONFIG_UML_TIME_TRAVEL_SUPPORT */ -extern unsigned long tt_extra_sched_jiffies; - /* * Without CONFIG_UML_TIME_TRAVEL_SUPPORT this is a linker error if used, * which is intentional since we really shouldn't link it in that case. diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c index a5beaea2967e..b09e85279d2b 100644 --- a/arch/um/kernel/skas/syscall.c +++ b/arch/um/kernel/skas/syscall.c @@ -31,17 +31,6 @@ void handle_syscall(struct uml_pt_regs *r) goto out; syscall = UPT_SYSCALL_NR(r); - - /* - * If no time passes, then sched_yield may not actually yield, causing - * broken spinlock implementations in userspace (ASAN) to hang for long - * periods of time. - */ - if ((time_travel_mode == TT_MODE_INFCPU || - time_travel_mode == TT_MODE_EXTERNAL) && - syscall == __NR_sched_yield) - tt_extra_sched_jiffies += 1; - if (syscall >= 0 && syscall < __NR_syscalls) { unsigned long ret = EXECUTE_SYSCALL(syscall, regs); |