kern: cpuset: drop the lock to allocate domainsets
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Authored by kevans on Nov 25 2020, 5:58 PM.

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andrew
markj

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rS368116: kern: cpuset: drop the lock to allocate domainsets

Summary

Restructure the loop a little bit to make it a little more clear how it really operates: we never allocate any domains at the beginning of the first iteration, and it will run until we've satisfied the amount we need or we encounter an error.

The lock is now taken outside of the loop to make stuff inside the loop easier to evaluate w.r.t. locking.

This fixes it to not try and allocate any domains for the freelist under the spinlock, which would have happened before if we needed any new domains.

Reported-by: syzbot+6743fa07b9b7528dc561@syzkaller.appspotmail.com

Diff Detail

Repository

rS FreeBSD src repository - subversion

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Build Status

Buildable 35035

Event Timeline

kevans created this revision.Nov 25 2020, 5:58 PM

Herald added a subscriber: imp. · View Herald TranscriptNov 25 2020, 5:58 PM

kevans requested review of this revision.Nov 25 2020, 5:58 PM

Harbormaster completed remote builds in B35035: Diff 79995.Nov 25 2020, 5:58 PM

kevans edited the summary of this revision. (Show Details)Nov 25 2020, 5:59 PM

Thanks. I tested this patch with syzkaller's repro for the bug, seems to be fixed.

Reported-by: syzbot+6743fa07b9b7528dc561@syzkaller.appspotmail.com

It'll still work if you write "Reported by:" as we normally do, i.e. without the dash.

This revision is now accepted and ready to land.Nov 25 2020, 6:13 PM

Closed by commit rS368116: kern: cpuset: drop the lock to allocate domainsets (authored by kevans). · Explain WhyNov 28 2020, 1:21 AM

This revision was automatically updated to reflect the committed changes.

kevans added a commit: rS368116: kern: cpuset: drop the lock to allocate domainsets.

Revision Contents
Changeset List

Path

Size

sys/

kern/

kern_cpuset.c

21 lines

Diff 79995

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sys/kern/kern_cpuset.c

Show First 20 Lines • Show All 81 Lines • ▼ Show 20 Lines	FBSD_1.0 {
fchdir;		fchdir;
fchflags;		fchflags;
fchmod;		fchmod;
fchown;		fchown;
fcntl;		fcntl;
fhopen;		fhopen;
flock;		flock;
fork;		fork;
fpathconf;		fpathconf;
		kibUnsubmitted Done Inline Actions Add context to the diff. Even without the context, I am sure that you put the symbols into the wrong namespace. kib: Add context to the diff. Even without the context, I am sure that you put the symbols into the…
		jack_gandi.netAuthorUnsubmitted Done Inline Actions Should I add a FBSD_1.6 section then? jack_gandi.net: Should I add a FBSD_1.6 section then?
		jack_gandi.netAuthorUnsubmitted Done Inline Actions nevermind, I just realized https://wiki.freebsd.org/AddingSyscalls says to put them in the most recent namespace (FBSD_1.5) jack_gandi.net: nevermind, I just realized https://wiki.freebsd.org/AddingSyscalls says to put them in the most…
fsync;		fsync;
futimes;		futimes;
getaudit;		getaudit;
getaudit_addr;		getaudit_addr;
getauid;		getauid;
getcontext;		getcontext;
getdtablesize;		getdtablesize;
getegid;		getegid;
▲ Show 20 Lines • Show All 285 Lines • ▼ Show 20 Lines	FBSD_1.5 {
fdatasync;		fdatasync;
fhstat;		fhstat;
fhstatfs;		fhstatfs;
fstat;		fstat;
fstatat;		fstatat;
fstatfs;		fstatfs;
getdents;		getdents;
getdirentries;		getdirentries;
getfsstat;		getfsstat;
		kibUnsubmitted Not Done Inline Actions No, FBSD_1.5 is wrong again. New 13-CURRENT symbols must go into FBSD_1.6. kib: No, FBSD_1.5 is wrong again. New 13-CURRENT symbols must go into FBSD_1.6.
getrandom;		getrandom;
kevent;		kevent;
lstat;		lstat;
mknod;		mknod;
mknodat;		mknodat;
stat;		stat;
statfs;		statfs;
cpuset_getdomain;		cpuset_getdomain;
cpuset_setdomain;		cpuset_setdomain;
};		};

		FBSD_1.6 {
		fhlink;
		fhlinkat;
		fhreadlink;
		getfhat;
		};

FBSDprivate_1.0 {		FBSDprivate_1.0 {
___acl_aclcheck_fd;		___acl_aclcheck_fd;
__sys___acl_aclcheck_fd;		__sys___acl_aclcheck_fd;
___acl_aclcheck_file;		___acl_aclcheck_file;
__sys___acl_aclcheck_file;		__sys___acl_aclcheck_file;
___acl_aclcheck_link;		___acl_aclcheck_link;
__sys___acl_aclcheck_link;		__sys___acl_aclcheck_link;
___acl_delete_fd;		___acl_delete_fd;
▲ Show 20 Lines • Show All 153 Lines • ▼ Show 20 Lines	FBSDprivate_1.0 {
__sys_fchown;		__sys_fchown;
_fcntl;		_fcntl;
__sys_fcntl;		__sys_fcntl;
__fcntl_compat;		__fcntl_compat;
_fhopen;		_fhopen;
__sys_fhopen;		__sys_fhopen;
_fhstat;		_fhstat;
__sys_fhstat;		__sys_fhstat;
_fhstatfs;		_fhstatfs;
		brooksUnsubmitted Done Inline Actions I believe it's unnecessary to add these as there are no potential consumers of these symbols. brooks: I believe it's unnecessary to add these as there are no potential consumers of these symbols.
__sys_fhstatfs;		__sys_fhstatfs;
_flock;		_flock;
__sys_flock;		__sys_flock;
_fork;		_fork;
__sys_fork;		__sys_fork;
_fpathconf;		_fpathconf;
__sys_fpathconf;		__sys_fpathconf;
_fstat;		_fstat;
▲ Show 20 Lines • Show All 443 Lines • Show Last 20 Lines

kern: cpuset: drop the lock to allocate domainsetsClosedPublicActions