From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Date: Tue, 23 Feb 2021 00:34:06 +0000 Subject: Re: 5.11 regression: "ia64: add support for TIF_NOTIFY_SIGNAL" breaks ia64 boot Message-Id: List-Id: References: <20210222230519.73f3e239@sf> <20210222235359.75d1a912@sf> In-Reply-To: <20210222235359.75d1a912@sf> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: Sergei Trofimovich Cc: linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org On 2/22/21 4:53 PM, Sergei Trofimovich wrote: > On Mon, 22 Feb 2021 16:34:50 -0700 > Jens Axboe wrote: >=20 >> On 2/22/21 4:05 PM, Sergei Trofimovich wrote: >>> Hia Jens! >>> >>> Tried 5.11 on rx3600 box and noticed it has >>> a problem handling init (5.10 booted fine): >>> >>> INIT: version 2.98 booting >>> >>> OpenRC 0.42.1 is starting up Gentoo Linux (ia64) >>> >>> mkdir `/run/openrc': Read-only file system >>> mkdir `/run/openrc/starting': No such file or directory >>> mkdir `/run/openrc/started': No such file or directory >>> mkdir `/run/openrc/stopping': No such file or directory >>> mkdir `/run/openrc/inactive': No such file or directory >>> mkdir `/run/openrc/wasinactive': No such file or directory >>> mkdir `/run/openrc/failed': No such file or directory >>> mkdir `/run/openrc/hotplugged': No such file or directory >>> mkdir `/run/openrc/daemons': No such file or directory >>> mkdir `/run[ 14.595059] Kernel panic - not syncing: Attempted to kill= init! exitcode=3D0x0000000b >>> [ 14.599059] ---[ end Kernel panic - not syncing: Attempted to kill i= nit! exitcode=3D0x0000000b ]--- >>> >>> I suspect we build bad signal stack frame for userspace. >>> >>> With a bit of #define DEBUG_SIG 1 enabled the signals are SIGCHLD: >>> >>> [ 34.969771] SIG deliver (gendepends.sh:69): sig=17 sp`000fffff6aeaa0= ip=A000000000040740 handler=000000004b4c59b6 >>> [ 34.969948] SIG deliver (init:1): sig=17 sp`000fffff1ccc50 ip=A00000= 0000040740 handler=000000004638b9e5 >>> [ 34.969948] SIG deliver (gendepends.sh:69): sig=17 sp`000fffff6adf90= ip=A000000000040740 handler=000000004b4c59b6 >>> [ 34.973948] SIG deliver (init:1): sig=17 sp`000fffff1cc140 ip=A00000= 0000040740 handler=000000004638b9e5 >>> [ 34.973948] Kernel panic - not syncing: Attempted to kill init! exit= code=3D0x0000000b >>> [ 34.973948] SIG deliver (gendepends.sh:69): sig=17 sp`000fffff6ad480= ip=A000000000040740 handler=000000004b4c59b6 >>> [ 34.973948] ---[ end Kernel panic - not syncing: Attempted to kill i= nit! exitcode=3D0x0000000b ]--- >>> >>> Bisect points at: >>> >>> commit b269c229b0e89aedb7943c06673b56b6052cf5e5 >>> Author: Jens Axboe >>> Date: Fri Oct 9 14:49:43 2020 -0600 >>> >>> ia64: add support for TIF_NOTIFY_SIGNAL >>> >>> Wire up TIF_NOTIFY_SIGNAL handling for ia64. >>> >>> Cc: linux-ia64@vger.kernel.org >>> [axboe: added fixes from Mike Rapoport ] >>> Signed-off-by: Jens Axboe >>> >>> diff --git a/arch/ia64/include/asm/thread_info.h b/arch/ia64/include/as= m/thread_info.h >>> index 64a1011f6812..51d20cb37706 100644 >>> --- a/arch/ia64/include/asm/thread_info.h >>> +++ b/arch/ia64/include/asm/thread_info.h >>> @@ -103,6 +103,7 @@ struct thread_info { >>> #define TIF_SYSCALL_TRACE 2 /* syscall trace active */ >>> #define TIF_SYSCALL_AUDIT 3 /* syscall auditing active */ >>> #define TIF_SINGLESTEP 4 /* restore singlestep on return= to user mode */ >>> +#define TIF_NOTIFY_SIGNAL 5 /* signal notification exist */ >>> #define TIF_NOTIFY_RESUME 6 /* resumption notification requ= ested */ >>> #define TIF_MEMDIE 17 /* is terminating due to OOM ki= ller */ >>> #define TIF_MCA_INIT 18 /* this task is processing MCA = or INIT */ >>> @@ -115,6 +116,7 @@ struct thread_info { >>> #define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP) >>> #define _TIF_SYSCALL_TRACEAUDIT (_TIF_SYSCALL_TRACE|_TIF_SYSCAL= L_AUDIT|_TIF_SINGLESTEP) >>> #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) >>> +#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) >>> #define _TIF_SIGPENDING (1 << TIF_SIGPENDING) >>> #define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED) >>> #define _TIF_MCA_INIT (1 << TIF_MCA_INIT) >>> @@ -124,7 +126,7 @@ struct thread_info { >>> >>> /* "work to do on user-return" bits */ >>> #define TIF_ALLWORK_MASK (_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TI= F_SYSCALL_AUDIT|\ >>> - _TIF_NEED_RESCHED|_TIF_SYSCALL_TRACE) >>> + _TIF_NEED_RESCHED|_TIF_SYSCALL_TRACE|_= TIF_NOTIFY_SIGNAL) >>> /* like TIF_ALLWORK_BITS but sans TIF_SYSCALL_TRACE or TIF_SYSCALL_AUD= IT */ >>> #define TIF_WORK_MASK (TIF_ALLWORK_MASK&~(_TIF_SYSCALL_TRACE|= _TIF_SYSCALL_AUDIT)) >>> >>> diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c >>> index 6b61a703bcf5..8d4e1cab9190 100644 >>> --- a/arch/ia64/kernel/process.c >>> +++ b/arch/ia64/kernel/process.c >>> @@ -171,7 +171,8 @@ do_notify_resume_user(sigset_t *unused, struct sigs= cratch *scr, long in_syscall) >>> } >>> >>> /* deal with pending signal delivery */ >>> - if (test_thread_flag(TIF_SIGPENDING)) { >>> + if (test_thread_flag(TIF_SIGPENDING) || >>> + test_thread_flag(TIF_NOTIFY_SIGNAL)) { >>> local_irq_enable(); /* force interrupt enable */ >>> ia64_do_signal(scr, in_syscall); >>> >>> which looks benign, but it enables a bit of conditional >>> TIF_NOTIFY_SIGNAL handling I don't understand. >>> >>> Can you help me get what is the interaction between >>> TIF_NOTIFY_SIGNAL and TIF_SIGPENDING for >>> simple processes without io_uring use case? >>> >>> I wonder if it's ia64_do_signal()' generates a signal >>> delivery when it should not. =20 >> >> Can you test: >> >> https://marc.info/?l=3Dlinux-ia64&m=161187407609443&w=3D1 >> >> with the addition mentioned here: >=20 > Not enough: >=20 > mkdir `/run/openrc': Read-only file system > mkdir `/run/openrc/starting': No such file or directory > mkdir `/run/openrc/started': No such file or directory > mkdir `/run/openrc/stopping': No such file or directory > mkdir `/run/openrc/inactive': No such file or directory > mkdir `/run/openrc/wasinactive': No such file or directory > mkdir `/run/openrc/failed': No such file or directory > mkdir `/run/openrc/hotplugged': No such file or directory > mkdir `/run/openrc/daemons': No such file or directory > [ 14.554357] Kernel panic - not syncing: Attempted to kill init! exitco= de=3D0x0000000b > [ 14.554357] ---[ end Kernel panic - not syncing: Attempted to kill ini= t! exitcode=3D0x0000000b ]--- > mkdir `/run/openrc/options': No such file or directory > mkdir `/run/openrc/exclusive': No such file or directory > mkdir `/run/openrc/scheduled': No such file or directory > mkdir `/run/openrc/tmp': No such file or directory >=20 >> https://marc.info/?l=3Dlinux-ia64&m=161187470709706&w=3D1 >> >> if needed? >=20 > Two patches above do fix the boot \o/ But have a lot of spam about > 'signal 0' delivery to a bunch of processes: >=20 > * Mounting /proc ... > [ ok ] > * Mounting /run ... > * /run/openrc: creating directory > * /run/lock: creating directory > * /run/lock: correcting owner > * Caching service dependencies ... > [ ok ] > * Mounting /sys ... > [ ok ] > * Mounting debug filesystem ... > [ ok ] > * Mounting efivarfs filesystem ... > [ ok ] > * sysfs: caught unknown signal 0 > * openrc: caught unknown signal 0 > * Mounting cgroup filesystem ... That's an improvement! Let me take a look at this tonight and see if I can figure out what's going on. But yes, it's the ia64 signal delivery being just different enough from the norm that it apparently triggers some weirdness. --=20 Jens Axboe