Branch: refs/heads/release-15.09
Home: https://github.com/NixOS/nixpkgs
Commit: c5691ed4243e96990ee3510d90aea0f252543c15
https://github.com/NixOS/nixpkgs/commit/c5691ed4243e96990ee3510d90aea0f252543c15
Author: aszlig <[email protected]>
Date: 2016-05-06 (Fri, 06 May 2016)
Changed paths:
M nixos/modules/system/boot/stage-1-init.sh
Log Message:
-----------
nixos/stage-1: Don't kill kernel threads
Unfortunately, pkill doesn't distinguish between kernel and user space
processes, so we need to make sure we don't accidentally kill kernel
threads.
Normally, a kernel thread ignores all signals, but there are a few that
do. A quick grep on the kernel source tree (as of kernel 4.6.0) shows
the following source files which use allow_signal():
drivers/isdn/mISDN/l1oip_core.c
drivers/md/md.c
drivers/misc/mic/cosm/cosm_scif_server.c
drivers/misc/mic/cosm_client/cosm_scif_client.c
drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c
drivers/staging/rtl8188eu/core/rtw_cmd.c
drivers/staging/rtl8712/rtl8712_cmd.c
drivers/target/iscsi/iscsi_target.c
drivers/target/iscsi/iscsi_target_login.c
drivers/target/iscsi/iscsi_target_nego.c
drivers/usb/atm/usbatm.c
drivers/usb/gadget/function/f_mass_storage.c
fs/jffs2/background.c
fs/lockd/clntlock.c
fs/lockd/svc.c
fs/nfs/nfs4state.c
fs/nfsd/nfssvc.c
While not all of these are necessarily kthreads and some functionality
may still be unimpeded, it's still quite harmful and can cause
unexpected side-effects, especially because some of these kthreads are
storage-related (which we obviously don't want to kill during bootup).
During discussion at #15226, @dezgeg suggested the following
implementation:
for pid in $(pgrep -v -f '@'); do
if [ "$(cat /proc/$pid/cmdline)" != "" ]; then
kill -9 "$pid"
fi
done
This has a few downsides:
* User space processes which use an empty string in their command line
won't be killed.
* It results in errors during bootup because some shell-related
processes are already terminated (maybe it's pgrep itself, haven't
checked).
* The @ is searched within the full command line, not just at the
beginning of the string. Of course, we already had this until now, so
it's not a problem of his implementation.
I posted an alternative implementation which doesn't suffer from the
first point, but even that one wasn't sufficient:
for pid in $(pgrep -v -f '^@'); do
readlink "/proc/$pid/exe" &> /dev/null || continue
echo "$pid"
done | xargs kill -9
This one spawns a subshell, which would be included in the processes to
kill and actually kills itself during the process.
So what we have now is even checking whether the shell process itself is
in the list to kill and avoids killing it just to be sure.
Also, we don't spawn a subshell anymore and use /proc/$pid/exe to
distinguish between user space and kernel processes like in the comments
of the following StackOverflow answer:
http://stackoverflow.com/a/12231039
We don't need to take care of terminating processes, because what we
actually want IS to terminate the processes.
The only point where this (and any previous) approach falls short if we
have processes that act like fork bombs, because they might spawn
additional processes between the pgrep and the killing. We can only
address this with process/control groups and this still won't save us
because the root user can escape from that as well.
Signed-off-by: aszlig <[email protected]>
Fixes: #15226
Commit: 263efd476e30a00deb44d9cb59c7e151fc9423a5
https://github.com/NixOS/nixpkgs/commit/263efd476e30a00deb44d9cb59c7e151fc9423a5
Author: aszlig <[email protected]>
Date: 2016-05-06 (Fri, 06 May 2016)
Changed paths:
M nixos/tests/installer.nix
Log Message:
-----------
nixos/tests/installer/swraid: Check for safemode
This is a regression test for #15226, so that the test will fail once we
accidentally kill one or more of the md kthreads (aka: if safe mode is
enabled).
Signed-off-by: aszlig <[email protected]>
Commit: a5b7e1c1b1cf6f96f5efbfe7b724d18ad3cc5c2e
https://github.com/NixOS/nixpkgs/commit/a5b7e1c1b1cf6f96f5efbfe7b724d18ad3cc5c2e
Author: aszlig <[email protected]>
Date: 2016-05-06 (Fri, 06 May 2016)
Changed paths:
M nixos/release.nix
A nixos/tests/boot-stage1.nix
Log Message:
-----------
nixos/tests: Add a test for boot stage 1
We already have a small regression test for #15226 within the swraid
installer test. Unfortunately, we only check there whether the md
kthread got signalled but not whether other rampaging processes are
still alive that *should* have been killed.
So in order to do this we provide multiple canary processes which are
checked after the system has booted up:
* canary1: It's a simple forking daemon which just sleeps until it's
going to be killed. Of course we expect this process to not
be alive anymore after boot up.
* canary2: Similar to canary1, but tries to mimick a kthread to make
sure that it's going to be properly killed at the end of
stage 1.
* canary3: Like canary2, but this time using a @ in front of its
command name to actually prevent it from being killed.
* kcanary: This one is a real kthread and it runs until killed, which
shouldn't be the case.
Tested with and without 67223ee and everything works as expected, at
least on my machine.
Signed-off-by: aszlig <[email protected]>
Commit: 10a671af4525b636c356bb72d4c46713a2f81ba6
https://github.com/NixOS/nixpkgs/commit/10a671af4525b636c356bb72d4c46713a2f81ba6
Author: aszlig <[email protected]>
Date: 2016-05-06 (Fri, 06 May 2016)
Changed paths:
M nixos/release-combined.nix
Log Message:
-----------
nixos/release-combined: Add boot-stage1 test
We don't want to push out a channel update whenever this test fails,
because that might have unexpected and confused side effects and it
*really* means that stage 1 of our boot up is broken.
Signed-off-by: aszlig <[email protected]>
Commit: fc88ff2a90454ed49c31544dbc6f7b6d8b57146c
https://github.com/NixOS/nixpkgs/commit/fc88ff2a90454ed49c31544dbc6f7b6d8b57146c
Author: aszlig <[email protected]>
Date: 2016-05-06 (Fri, 06 May 2016)
Changed paths:
M nixos/tests/boot-stage1.nix
Log Message:
-----------
nixos/tests/boot-stage1: Add myself to maintainers
As @edolstra pointed out that the kernel module might be painful to
maintain. I strongly disagree because it's only a small module and it's
good to have such a canary in the tests no matter how the bootup process
looks like, so I'm going the masochistic route and try to maintain it.
If it *really* becomes too much maintenance burden, we can still drop or
disable kcanary.
Signed-off-by: aszlig <[email protected]>
Commit: 6edbeb8b4723eb1682cac7760ad8cfa6049d9253
https://github.com/NixOS/nixpkgs/commit/6edbeb8b4723eb1682cac7760ad8cfa6049d9253
Author: aszlig <[email protected]>
Date: 2016-05-06 (Fri, 06 May 2016)
Changed paths:
M nixos/modules/system/boot/stage-1-init.sh
M nixos/release-combined.nix
M nixos/release.nix
A nixos/tests/boot-stage1.nix
M nixos/tests/installer.nix
Log Message:
-----------
Merge branch 'stage1-dont-kill-kthreads'
Merges pull request #15275:
This addresses #15226 and fixes killing of processes before
switching from the initrd to the real root.
Right now, the pkill that is issued not only kills user space
processes but also sends a SIGKILL to kernel threads as well.
Usually these threads ignore signals, but some of these processes do
handle signals, like for example the md module, which happened in
#15226.
It also adds a small check for the swraid installer test and a
standalone test which checks on just that problem, so in the future
this shouldn't happen again.
This has been acked by @edolstra on IRC.
The reason I'm merging this to 15.09 is that this branch fixes #15226
and thus also fixes mdraid setups out there.
Tested using the boot-stage1.nix NixOS test against release-15.09.
Compare: https://github.com/NixOS/nixpkgs/compare/8a6b697af6b9...6edbeb8b4723_______________________________________________
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