* Re: add file system helpers that take kernel pointers for the init code v4 [not found] <20200728163416.556521-1-hch@lst.de> @ 2020-08-03 14:56 ` Qian Cai 2020-08-03 15:08 ` Christoph Hellwig 0 siblings, 1 reply; 2+ messages in thread From: Qian Cai @ 2020-08-03 14:56 UTC (permalink / raw) To: Christoph Hellwig Cc: Al Viro, Linus Torvalds, Greg Kroah-Hartman, Rafael J. Wysocki, linux-kernel, linux-raid, linux-fsdevel, linux-api, sfr, linux-next On Tue, Jul 28, 2020 at 06:33:53PM +0200, Christoph Hellwig wrote: > Hi Al and Linus, > > currently a lot of the file system calls in the early in code (and the > devtmpfs kthread) rely on the implicit set_fs(KERNEL_DS) during boot. > This is one of the few last remaining places we need to deal with to kill > off set_fs entirely, so this series adds new helpers that take kernel > pointers. These helpers are in init/ and marked __init and thus will > be discarded after bootup. A few also need to be duplicated in devtmpfs, > though unfortunately. Reverting this series from next-20200803 fixed the crash below on shutdown. [ 7303.287890][ T1] systemd-shutdown[1]: All loop devices detached. [ 7303.287930][ T1] systemd-shutdown[1]: Detaching DM devices. [ 7303.441674][ T1] printk: shutdown: 9 output lines suppressed due to ratelimiting [ 7303.443999][ T1] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000100 [ 7303.444027][ T1] CPU: 120 PID: 1 Comm: shutdown Not tainted 5.8.0-next-20200803 #2 [ 7303.444053][ T1] Call Trace: [ 7303.444069][ T1] [c000000015d27b70] [c0000000006f3778] dump_stack+0xfc/0x174 (unreliable) [ 7303.444103][ T1] [c000000015d27bc0] [c0000000000c9328] panic+0x214/0x4ac [ 7303.444140][ T1] [c000000015d27c60] [c0000000000d4d28] do_exit+0xda8/0xee0 [ 7303.444178][ T1] [c000000015d27d60] [c0000000000d4f1c] do_group_exit+0x5c/0xd0 list_empty at include/linux/list.h:282 (inlined by) thread_group_empty at include/linux/sched/signal.h:671 (inlined by) do_group_exit at kernel/exit.c:888 [ 7303.444205][ T1] [c000000015d27da0] [c0000000000d4fac] sys_exit_group+0x1c/0x20 sys_exit_group at kernel/exit.c:914 [ 7303.444234][ T1] [c000000015d27dc0] [c00000000002c628] system_call_exception+0xf8/0x1d0 [ 7303.444262][ T1] [c000000015d27e20] [c00000000000d0a8] system_call_common+0xe8/0x218 [ 7304.936912][ T1] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000100 ]--- > > The series sits on top of my previous > > "decruft the early init / initrd / initramfs code v2" > > series. > > > Git tree: > > git://git.infradead.org/users/hch/misc.git init_path > > Gitweb: > > http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/init_path > > > Changes since v3: > - rename fs/for_init.c to fs/init.c > - document the purpose of the routines in fs/init.c with a comment > - don't mark devtmpfs __init as that will cause it to get overwritten > by initmem poisoning > - add an init_dup helper to make Al more happy than with the version > commit to the "decruft the early init / initrd / initramfs code v2" > series > > Changes since v2: > - move to fs/for_init.c > - reuse the init routines in devtmpfs after refactoring devtmpfsd > (and thus the broken error handling in the previous version) > - actually use kern_path in a place where user_path_at sneaked back in > > Changes since v1: > - avoid most core VFS changes > - renamed the functions and move them to init/ and devtmpfs > - drop a bunch of cleanups that can be submitted independently now > > > Diffstat: ^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: add file system helpers that take kernel pointers for the init code v4 2020-08-03 14:56 ` add file system helpers that take kernel pointers for the init code v4 Qian Cai @ 2020-08-03 15:08 ` Christoph Hellwig 0 siblings, 0 replies; 2+ messages in thread From: Christoph Hellwig @ 2020-08-03 15:08 UTC (permalink / raw) To: Qian Cai Cc: Christoph Hellwig, Al Viro, Linus Torvalds, Greg Kroah-Hartman, Rafael J. Wysocki, linux-kernel, linux-raid, linux-fsdevel, linux-api, sfr, linux-next On Mon, Aug 03, 2020 at 10:56:23AM -0400, Qian Cai wrote: > On Tue, Jul 28, 2020 at 06:33:53PM +0200, Christoph Hellwig wrote: > > Hi Al and Linus, > > > > currently a lot of the file system calls in the early in code (and the > > devtmpfs kthread) rely on the implicit set_fs(KERNEL_DS) during boot. > > This is one of the few last remaining places we need to deal with to kill > > off set_fs entirely, so this series adds new helpers that take kernel > > pointers. These helpers are in init/ and marked __init and thus will > > be discarded after bootup. A few also need to be duplicated in devtmpfs, > > though unfortunately. > > Reverting this series from next-20200803 fixed the crash below on shutdown. Please try this patch: --- From 6448eebe2fe7189cedc5136ab3464517956922b7 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig <hch@lst.de> Date: Mon, 3 Aug 2020 15:56:18 +0200 Subject: init: fix init_dup Don't allocate an unused fd for each call. Also drop the extra reference from filp_open after the init_dup calls while we're at it. Fixes: 36e96b411649 ("init: add an init_dup helper") Reported-by Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Christoph Hellwig <hch@lst.de> --- fs/init.c | 2 +- init/main.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/init.c b/fs/init.c index 730e05acda2392..e9c320a48cf157 100644 --- a/fs/init.c +++ b/fs/init.c @@ -260,6 +260,6 @@ int __init init_dup(struct file *file) fd = get_unused_fd_flags(0); if (fd < 0) return fd; - fd_install(get_unused_fd_flags(0), get_file(file)); + fd_install(fd, get_file(file)); return 0; } diff --git a/init/main.c b/init/main.c index 089e21504b1fc1..9dae9c4f806bb9 100644 --- a/init/main.c +++ b/init/main.c @@ -1470,6 +1470,7 @@ void __init console_on_rootfs(void) init_dup(file); init_dup(file); init_dup(file); + fput(file); } static noinline void __init kernel_init_freeable(void) -- 2.27.0 ^ permalink raw reply related [flat|nested] 2+ messages in thread
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2020-08-03 14:56 ` add file system helpers that take kernel pointers for the init code v4 Qian Cai
2020-08-03 15:08 ` Christoph Hellwig
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