Signals control #8

l0kod · 2024-01-18T19:10:21Z

A sandboxed process is currently not restricted to send signals (e.g. SIGKILL) to processes outside the sandbox. A simple way to control that would be to scope signals the same way ptrace is restricted (but this time it would be opt-in).

See https://lore.kernel.org/all/20231023.ahphah4Wii4v@digikod.net/

Approach similar to #7

v2: https://lore.kernel.org/all/cover.1722966592.git.fahimitahera@gmail.com/
v1: https://lore.kernel.org/all/36958dbc486e1f975f4d4ecdfa51ae65c2c4ced0.1720213293.git.fahimitahera@gmail.com/

The text was updated successfully, but these errors were encountered:

maryagiamah · 2024-03-06T10:45:37Z

Hello, can I work on this ?

l0kod · 2024-03-06T15:41:15Z

Hi @maryagiamah! Yes, you can start working on signals control.

l0kod · 2024-03-07T08:50:08Z

What is your plan to work on this?

maryagiamah · 2024-03-07T09:53:53Z

I have little idea about what it entails as I have experimented with signals prior but I am still reading up on what the task is all about. Do you have any route or path I should go searching for?

…

On Thu, 7 Mar 2024, 09:50 Mickaël Salaün, ***@***.***> wrote: What is your plan to work on this? — Reply to this email directly, view it on GitHub <#8 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/A2PHWBHPIBGLFDMV6Q62P63YXAS5LAVCNFSM6AAAAABCAZJ4VOVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMYTSOBSHE4DSOJRHE> . You are receiving this because you were assigned.Message ID: ***@***.***>

l0kod · 2024-03-07T16:23:50Z

I have little idea about what it entails as I have experimented with signals prior but I am still reading up on what the task is all about. Do you have any route or path I should go searching for?

You first need to familiarize yourself with the Linux kernel development as explained in the Outreachy documentation. Then, you can start tweaking the code and test it with the test tools. If you have questions about that, please send emails to the Outreachy mailing list (CCing me and @pcmoore).

Before patching the kernel, you can start by thinking about attack scenarios using signals, describing them, and write such tests in a new file here.

About the kernel changes, we need to add a new scoped field to the landlock_ruleset_attr struct. This field will optionally contain a LANDLOCK_RULESET_SCOPED_SIGNAL flag to specify that this ruleset will deny any signal from within the sandbox to its parents (i.e. any parent sandbox or not-sandboxed processes).

This kind of restriction should be pretty similar to the ptrace ones, but we need to keep in mind that not all layers (i.e. nested sandboxes) of a Landlock domain may have this restriction. It could be seen as a roadblock for signals.

There is an LSM hook dedicated to control signals, and the Landlock scope logic is defined in ptrace.c (being renamed to task.c).

This GitHub issue is dedicated to track progress on signal control. As a reminder, no Linux kernel code change nor review should happen on GitHub because kernel reviewers are only following the dedicated mailing lists.

l0kod · 2024-03-27T12:24:21Z

Any news @maryagiamah?

tahifahimi · 2024-07-06T21:21:13Z

V1: https://lore.kernel.org/outreachy/36958dbc486e1f975f4d4ecdfa51ae65c2c4ced0.1720213293.git.fahimitahera@gmail.com/T/#t

[ Upstream commit a699781 ] A sysfs reader can race with a device reset or removal, attempting to read device state when the device is not actually present. eg: [exception RIP: qed_get_current_link+17] #8 [ffffb9e4f2907c48] qede_get_link_ksettings at ffffffffc07a994a [qede] #9 [ffffb9e4f2907cd8] __rh_call_get_link_ksettings at ffffffff992b01a3 #10 [ffffb9e4f2907d38] __ethtool_get_link_ksettings at ffffffff992b04e4 #11 [ffffb9e4f2907d90] duplex_show at ffffffff99260300 #12 [ffffb9e4f2907e38] dev_attr_show at ffffffff9905a01c #13 [ffffb9e4f2907e50] sysfs_kf_seq_show at ffffffff98e0145b #14 [ffffb9e4f2907e68] seq_read at ffffffff98d902e3 #15 [ffffb9e4f2907ec8] vfs_read at ffffffff98d657d1 #16 [ffffb9e4f2907f00] ksys_read at ffffffff98d65c3f #17 [ffffb9e4f2907f38] do_syscall_64 at ffffffff98a052fb crash> struct net_device.state ffff9a9d21336000 state = 5, state 5 is __LINK_STATE_START (0b1) and __LINK_STATE_NOCARRIER (0b100). The device is not present, note lack of __LINK_STATE_PRESENT (0b10). This is the same sort of panic as observed in commit 4224cfd ("net-sysfs: add check for netdevice being present to speed_show"). There are many other callers of __ethtool_get_link_ksettings() which don't have a device presence check. Move this check into ethtool to protect all callers. Fixes: d519e17 ("net: export device speed and duplex via sysfs") Fixes: 4224cfd ("net-sysfs: add check for netdevice being present to speed_show") Signed-off-by: Jamie Bainbridge <jamie.bainbridge@gmail.com> Link: https://patch.msgid.link/8bae218864beaa44ed01628140475b9bf641c5b0.1724393671.git.jamie.bainbridge@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>

Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit 1934b21 ("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit 26f2043 ("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: landlock-lsm#8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>

l0kod · 2024-09-25T15:19:17Z

Merged in e1b061b, but a test is still missing to align with the #7 tests.

l0kod · 2024-09-30T12:27:06Z

Related syzkaller change:

sys/linux: add Landlock scopes for Linux 6.12 google/syzkaller#5350

gnoack · 2024-11-15T10:47:11Z

Related go-landlock PR: landlock-lsm/go-landlock#33

During this PR, I discovered that signal scoping is potentially at odds with the way how Landlock gets enforced in multithreaded applications. Because landlock_restrict_self is inherently a single-threaded operation, in go-landlock, we use libpsx. This library implements the enforcement for all threads, but it does that by registering a special signal handler on all threads and then letting all threads do landlock_restrict_self individually. As a consequence:

Landlock domains on different OS threads are technically speaking enforced separately from each other, and are different Landlock domains as far as the kernel is concerned. ==> When signal scopes are enabled, the separate OS threads of that process can not send each other signals any more.
Because libpsx also in itself uses signals between these threads to enforce Landlock rulesets, libpsx can not be used correctly any more, affecting operations like (a) further landlock enforcement and (b) other psx-based glibc functionality such as setuid(2) and friends (compare setuid(2) VERSIONS section and nptl(7))

l0kod · 2024-12-04T10:37:06Z

This is unfortunate... For now, I think go-landlock should still implement abstract unix socket scoping but not expose the signal scoping with the related Landlock ABI (6). Signal scoping support could be delayed until the implementation of #2.

[ Upstream commit a848c29 ] On the node of an NFS client, some files saved in the mountpoint of the NFS server were copied to another location of the same NFS server. Accidentally, the nfs42_complete_copies() got a NULL-pointer dereference crash with the following syslog: [232064.838881] NFSv4: state recovery failed for open file nfs/pvc-12b5200d-cd0f-46a3-b9f0-af8f4fe0ef64.qcow2, error = -116 [232064.839360] NFSv4: state recovery failed for open file nfs/pvc-12b5200d-cd0f-46a3-b9f0-af8f4fe0ef64.qcow2, error = -116 [232066.588183] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000058 [232066.588586] Mem abort info: [232066.588701] ESR = 0x0000000096000007 [232066.588862] EC = 0x25: DABT (current EL), IL = 32 bits [232066.589084] SET = 0, FnV = 0 [232066.589216] EA = 0, S1PTW = 0 [232066.589340] FSC = 0x07: level 3 translation fault [232066.589559] Data abort info: [232066.589683] ISV = 0, ISS = 0x00000007 [232066.589842] CM = 0, WnR = 0 [232066.589967] user pgtable: 64k pages, 48-bit VAs, pgdp=00002000956ff400 [232066.590231] [0000000000000058] pgd=08001100ae100003, p4d=08001100ae100003, pud=08001100ae100003, pmd=08001100b3c00003, pte=0000000000000000 [232066.590757] Internal error: Oops: 96000007 [#1] SMP [232066.590958] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm vhost_net vhost vhost_iotlb tap tun ipt_rpfilter xt_multiport ip_set_hash_ip ip_set_hash_net xfrm_interface xfrm6_tunnel tunnel4 tunnel6 esp4 ah4 wireguard libcurve25519_generic veth xt_addrtype xt_set nf_conntrack_netlink ip_set_hash_ipportnet ip_set_hash_ipportip ip_set_bitmap_port ip_set_hash_ipport dummy ip_set ip_vs_sh ip_vs_wrr ip_vs_rr ip_vs iptable_filter sch_ingress nfnetlink_cttimeout vport_gre ip_gre ip_tunnel gre vport_geneve geneve vport_vxlan vxlan ip6_udp_tunnel udp_tunnel openvswitch nf_conncount dm_round_robin dm_service_time dm_multipath xt_nat xt_MASQUERADE nft_chain_nat nf_nat xt_mark xt_conntrack xt_comment nft_compat nft_counter nf_tables nfnetlink ocfs2 ocfs2_nodemanager ocfs2_stackglue iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ipmi_ssif nbd overlay 8021q garp mrp bonding tls rfkill sunrpc ext4 mbcache jbd2 [232066.591052] vfat fat cas_cache cas_disk ses enclosure scsi_transport_sas sg acpi_ipmi ipmi_si ipmi_devintf ipmi_msghandler ip_tables vfio_pci vfio_pci_core vfio_virqfd vfio_iommu_type1 vfio dm_mirror dm_region_hash dm_log dm_mod nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter bridge stp llc fuse xfs libcrc32c ast drm_vram_helper qla2xxx drm_kms_helper syscopyarea crct10dif_ce sysfillrect ghash_ce sysimgblt sha2_ce fb_sys_fops cec sha256_arm64 sha1_ce drm_ttm_helper ttm nvme_fc igb sbsa_gwdt nvme_fabrics drm nvme_core i2c_algo_bit i40e scsi_transport_fc megaraid_sas aes_neon_bs [232066.596953] CPU: 6 PID: 4124696 Comm: 10.253.166.125- Kdump: loaded Not tainted 5.15.131-9.cl9_ocfs2.aarch64 #1 [232066.597356] Hardware name: Great Wall .\x93\x8e...RF6260 V5/GWMSSE2GL1T, BIOS T656FBE_V3.0.18 2024-01-06 [232066.597721] pstate: 20400009 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [232066.598034] pc : nfs4_reclaim_open_state+0x220/0x800 [nfsv4] [232066.598327] lr : nfs4_reclaim_open_state+0x12c/0x800 [nfsv4] [232066.598595] sp : ffff8000f568fc70 [232066.598731] x29: ffff8000f568fc70 x28: 0000000000001000 x27: ffff21003db33000 [232066.599030] x26: ffff800005521ae0 x25: ffff0100f98fa3f0 x24: 0000000000000001 [232066.599319] x23: ffff800009920008 x22: ffff21003db33040 x21: ffff21003db33050 [232066.599628] x20: ffff410172fe9e40 x19: ffff410172fe9e00 x18: 0000000000000000 [232066.599914] x17: 0000000000000000 x16: 0000000000000004 x15: 0000000000000000 [232066.600195] x14: 0000000000000000 x13: ffff800008e685a8 x12: 00000000eac0c6e6 [232066.600498] x11: 0000000000000000 x10: 0000000000000008 x9 : ffff8000054e5828 [232066.600784] x8 : 00000000ffffffbf x7 : 0000000000000001 x6 : 000000000a9eb14a [232066.601062] x5 : 0000000000000000 x4 : ffff70ff8a14a800 x3 : 0000000000000058 [232066.601348] x2 : 0000000000000001 x1 : 54dce46366daa6c6 x0 : 0000000000000000 [232066.601636] Call trace: [232066.601749] nfs4_reclaim_open_state+0x220/0x800 [nfsv4] [232066.601998] nfs4_do_reclaim+0x1b8/0x28c [nfsv4] [232066.602218] nfs4_state_manager+0x928/0x10f0 [nfsv4] [232066.602455] nfs4_run_state_manager+0x78/0x1b0 [nfsv4] [232066.602690] kthread+0x110/0x114 [232066.602830] ret_from_fork+0x10/0x20 [232066.602985] Code: 1400000d f9403f20 f9402e61 91016003 (f9402c00) [232066.603284] SMP: stopping secondary CPUs [232066.606936] Starting crashdump kernel... [232066.607146] Bye! Analysing the vmcore, we know that nfs4_copy_state listed by destination nfs_server->ss_copies was added by the field copies in handle_async_copy(), and we found a waiting copy process with the stack as: PID: 3511963 TASK: ffff710028b47e00 CPU: 0 COMMAND: "cp" #0 [ffff8001116ef740] __switch_to at ffff8000081b92f4 #1 [ffff8001116ef760] __schedule at ffff800008dd0650 #2 [ffff8001116ef7c0] schedule at ffff800008dd0a00 #3 [ffff8001116ef7e0] schedule_timeout at ffff800008dd6aa0 #4 [ffff8001116ef860] __wait_for_common at ffff800008dd166c #5 [ffff8001116ef8e0] wait_for_completion_interruptible at ffff800008dd1898 #6 [ffff8001116ef8f0] handle_async_copy at ffff8000055142f4 [nfsv4] #7 [ffff8001116ef970] _nfs42_proc_copy at ffff8000055147c8 [nfsv4] #8 [ffff8001116efa80] nfs42_proc_copy at ffff800005514cf0 [nfsv4] #9 [ffff8001116efc50] __nfs4_copy_file_range.constprop.0 at ffff8000054ed694 [nfsv4] The NULL-pointer dereference was due to nfs42_complete_copies() listed the nfs_server->ss_copies by the field ss_copies of nfs4_copy_state. So the nfs4_copy_state address ffff0100f98fa3f0 was offset by 0x10 and the data accessed through this pointer was also incorrect. Generally, the ordered list nfs4_state_owner->so_states indicate open(O_RDWR) or open(O_WRITE) states are reclaimed firstly by nfs4_reclaim_open_state(). When destination state reclaim is failed with NFS_STATE_RECOVERY_FAILED and copies are not deleted in nfs_server->ss_copies, the source state may be passed to the nfs42_complete_copies() process earlier, resulting in this crash scene finally. To solve this issue, we add a list_head nfs_server->ss_src_copies for a server-to-server copy specially. Fixes: 0e65a32 ("NFS: handle source server reboot") Signed-off-by: Yanjun Zhang <zhangyanjun@cestc.cn> Reviewed-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>

commit cf96b8e upstream. ASan reports a memory leak caused by evlist not being deleted on exit in perf-report, perf-script and perf-data. The problem is caused by evlist->session not being deleted, which is allocated in perf_session__read_header, called in perf_session__new if perf_data is in read mode. In case of write mode, the session->evlist is filled by the caller. This patch solves the problem by calling evlist__delete in perf_session__delete if perf_data is in read mode. Changes in v2: - call evlist__delete from within perf_session__delete v1: https://lore.kernel.org/lkml/20210621234317.235545-1-rickyman7@gmail.com/ ASan report follows: $ ./perf script report flamegraph ================================================================= ==227640==ERROR: LeakSanitizer: detected memory leaks <SNIP unrelated> Indirect leak of 2704 byte(s) in 1 object(s) allocated from: #0 0x4f4137 in calloc (/home/user/linux/tools/perf/perf+0x4f4137) #1 0xbe3d56 in zalloc /home/user/linux/tools/lib/perf/../../lib/zalloc.c:8:9 #2 0x7f999e in evlist__new /home/user/linux/tools/perf/util/evlist.c:77:26 #3 0x8ad938 in perf_session__read_header /home/user/linux/tools/perf/util/header.c:3797:20 #4 0x8ec714 in perf_session__open /home/user/linux/tools/perf/util/session.c:109:6 #5 0x8ebe83 in perf_session__new /home/user/linux/tools/perf/util/session.c:213:10 #6 0x60c6de in cmd_script /home/user/linux/tools/perf/builtin-script.c:3856:12 #7 0x7b2930 in run_builtin /home/user/linux/tools/perf/perf.c:313:11 #8 0x7b120f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8 #9 0x7b2493 in run_argv /home/user/linux/tools/perf/perf.c:409:2 #10 0x7b0c89 in main /home/user/linux/tools/perf/perf.c:539:3 #11 0x7f5260654b74 (/lib64/libc.so.6+0x27b74) Indirect leak of 568 byte(s) in 1 object(s) allocated from: #0 0x4f4137 in calloc (/home/user/linux/tools/perf/perf+0x4f4137) #1 0xbe3d56 in zalloc /home/user/linux/tools/lib/perf/../../lib/zalloc.c:8:9 #2 0x80ce88 in evsel__new_idx /home/user/linux/tools/perf/util/evsel.c:268:24 #3 0x8aed93 in evsel__new /home/user/linux/tools/perf/util/evsel.h:210:9 #4 0x8ae07e in perf_session__read_header /home/user/linux/tools/perf/util/header.c:3853:11 #5 0x8ec714 in perf_session__open /home/user/linux/tools/perf/util/session.c:109:6 #6 0x8ebe83 in perf_session__new /home/user/linux/tools/perf/util/session.c:213:10 #7 0x60c6de in cmd_script /home/user/linux/tools/perf/builtin-script.c:3856:12 #8 0x7b2930 in run_builtin /home/user/linux/tools/perf/perf.c:313:11 #9 0x7b120f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8 #10 0x7b2493 in run_argv /home/user/linux/tools/perf/perf.c:409:2 #11 0x7b0c89 in main /home/user/linux/tools/perf/perf.c:539:3 #12 0x7f5260654b74 (/lib64/libc.so.6+0x27b74) Indirect leak of 264 byte(s) in 1 object(s) allocated from: #0 0x4f4137 in calloc (/home/user/linux/tools/perf/perf+0x4f4137) #1 0xbe3d56 in zalloc /home/user/linux/tools/lib/perf/../../lib/zalloc.c:8:9 #2 0xbe3e70 in xyarray__new /home/user/linux/tools/lib/perf/xyarray.c:10:23 #3 0xbd7754 in perf_evsel__alloc_id /home/user/linux/tools/lib/perf/evsel.c:361:21 #4 0x8ae201 in perf_session__read_header /home/user/linux/tools/perf/util/header.c:3871:7 #5 0x8ec714 in perf_session__open /home/user/linux/tools/perf/util/session.c:109:6 #6 0x8ebe83 in perf_session__new /home/user/linux/tools/perf/util/session.c:213:10 #7 0x60c6de in cmd_script /home/user/linux/tools/perf/builtin-script.c:3856:12 #8 0x7b2930 in run_builtin /home/user/linux/tools/perf/perf.c:313:11 #9 0x7b120f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8 #10 0x7b2493 in run_argv /home/user/linux/tools/perf/perf.c:409:2 #11 0x7b0c89 in main /home/user/linux/tools/perf/perf.c:539:3 #12 0x7f5260654b74 (/lib64/libc.so.6+0x27b74) Indirect leak of 32 byte(s) in 1 object(s) allocated from: #0 0x4f4137 in calloc (/home/user/linux/tools/perf/perf+0x4f4137) #1 0xbe3d56 in zalloc /home/user/linux/tools/lib/perf/../../lib/zalloc.c:8:9 #2 0xbd77e0 in perf_evsel__alloc_id /home/user/linux/tools/lib/perf/evsel.c:365:14 #3 0x8ae201 in perf_session__read_header /home/user/linux/tools/perf/util/header.c:3871:7 #4 0x8ec714 in perf_session__open /home/user/linux/tools/perf/util/session.c:109:6 #5 0x8ebe83 in perf_session__new /home/user/linux/tools/perf/util/session.c:213:10 #6 0x60c6de in cmd_script /home/user/linux/tools/perf/builtin-script.c:3856:12 #7 0x7b2930 in run_builtin /home/user/linux/tools/perf/perf.c:313:11 #8 0x7b120f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8 #9 0x7b2493 in run_argv /home/user/linux/tools/perf/perf.c:409:2 #10 0x7b0c89 in main /home/user/linux/tools/perf/perf.c:539:3 #11 0x7f5260654b74 (/lib64/libc.so.6+0x27b74) Indirect leak of 7 byte(s) in 1 object(s) allocated from: #0 0x4b8207 in strdup (/home/user/linux/tools/perf/perf+0x4b8207) #1 0x8b4459 in evlist__set_event_name /home/user/linux/tools/perf/util/header.c:2292:16 #2 0x89d862 in process_event_desc /home/user/linux/tools/perf/util/header.c:2313:3 #3 0x8af319 in perf_file_section__process /home/user/linux/tools/perf/util/header.c:3651:9 #4 0x8aa6e9 in perf_header__process_sections /home/user/linux/tools/perf/util/header.c:3427:9 #5 0x8ae3e7 in perf_session__read_header /home/user/linux/tools/perf/util/header.c:3886:2 #6 0x8ec714 in perf_session__open /home/user/linux/tools/perf/util/session.c:109:6 #7 0x8ebe83 in perf_session__new /home/user/linux/tools/perf/util/session.c:213:10 #8 0x60c6de in cmd_script /home/user/linux/tools/perf/builtin-script.c:3856:12 #9 0x7b2930 in run_builtin /home/user/linux/tools/perf/perf.c:313:11 #10 0x7b120f in handle_internal_command /home/user/linux/tools/perf/perf.c:365:8 #11 0x7b2493 in run_argv /home/user/linux/tools/perf/perf.c:409:2 #12 0x7b0c89 in main /home/user/linux/tools/perf/perf.c:539:3 #13 0x7f5260654b74 (/lib64/libc.so.6+0x27b74) SUMMARY: AddressSanitizer: 3728 byte(s) leaked in 7 allocation(s). Signed-off-by: Riccardo Mancini <rickyman7@gmail.com> Acked-by: Ian Rogers <irogers@google.com> Acked-by: Jiri Olsa <jolsa@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Leo Yan <leo.yan@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lore.kernel.org/lkml/20210624231926.212208-1-rickyman7@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: stable@vger.kernel.org # 5.10.228 Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit 9ca3144 ] The referenced commits introduced a two-step process for deleting FTEs: - Lock the FTE, delete it from hardware, set the hardware deletion function to NULL and unlock the FTE. - Lock the parent flow group, delete the software copy of the FTE, and remove it from the xarray. However, this approach encounters a race condition if a rule with the same match value is added simultaneously. In this scenario, fs_core may set the hardware deletion function to NULL prematurely, causing a panic during subsequent rule deletions. To prevent this, ensure the active flag of the FTE is checked under a lock, which will prevent the fs_core layer from attaching a new steering rule to an FTE that is in the process of deletion. [ 438.967589] MOSHE: 2496 mlx5_del_flow_rules del_hw_func [ 438.968205] ------------[ cut here ]------------ [ 438.968654] refcount_t: decrement hit 0; leaking memory. [ 438.969249] WARNING: CPU: 0 PID: 8957 at lib/refcount.c:31 refcount_warn_saturate+0xfb/0x110 [ 438.970054] Modules linked in: act_mirred cls_flower act_gact sch_ingress openvswitch nsh mlx5_vdpa vringh vhost_iotlb vdpa mlx5_ib mlx5_core xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm ib_uverbs ib_core zram zsmalloc fuse [last unloaded: cls_flower] [ 438.973288] CPU: 0 UID: 0 PID: 8957 Comm: tc Not tainted 6.12.0-rc1+ #8 [ 438.973888] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 438.974874] RIP: 0010:refcount_warn_saturate+0xfb/0x110 [ 438.975363] Code: 40 66 3b 82 c6 05 16 e9 4d 01 01 e8 1f 7c a0 ff 0f 0b c3 cc cc cc cc 48 c7 c7 10 66 3b 82 c6 05 fd e8 4d 01 01 e8 05 7c a0 ff <0f> 0b c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 [ 438.976947] RSP: 0018:ffff888124a53610 EFLAGS: 00010286 [ 438.977446] RAX: 0000000000000000 RBX: ffff888119d56de0 RCX: 0000000000000000 [ 438.978090] RDX: ffff88852c828700 RSI: ffff88852c81b3c0 RDI: ffff88852c81b3c0 [ 438.978721] RBP: ffff888120fa0e88 R08: 0000000000000000 R09: ffff888124a534b0 [ 438.979353] R10: 0000000000000001 R11: 0000000000000001 R12: ffff888119d56de0 [ 438.979979] R13: ffff888120fa0ec0 R14: ffff888120fa0ee8 R15: ffff888119d56de0 [ 438.980607] FS: 00007fe6dcc0f800(0000) GS:ffff88852c800000(0000) knlGS:0000000000000000 [ 438.983984] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 438.984544] CR2: 00000000004275e0 CR3: 0000000186982001 CR4: 0000000000372eb0 [ 438.985205] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 438.985842] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 438.986507] Call Trace: [ 438.986799] <TASK> [ 438.987070] ? __warn+0x7d/0x110 [ 438.987426] ? refcount_warn_saturate+0xfb/0x110 [ 438.987877] ? report_bug+0x17d/0x190 [ 438.988261] ? prb_read_valid+0x17/0x20 [ 438.988659] ? handle_bug+0x53/0x90 [ 438.989054] ? exc_invalid_op+0x14/0x70 [ 438.989458] ? asm_exc_invalid_op+0x16/0x20 [ 438.989883] ? refcount_warn_saturate+0xfb/0x110 [ 438.990348] mlx5_del_flow_rules+0x2f7/0x340 [mlx5_core] [ 438.990932] __mlx5_eswitch_del_rule+0x49/0x170 [mlx5_core] [ 438.991519] ? mlx5_lag_is_sriov+0x3c/0x50 [mlx5_core] [ 438.992054] ? xas_load+0x9/0xb0 [ 438.992407] mlx5e_tc_rule_unoffload+0x45/0xe0 [mlx5_core] [ 438.993037] mlx5e_tc_del_fdb_flow+0x2a6/0x2e0 [mlx5_core] [ 438.993623] mlx5e_flow_put+0x29/0x60 [mlx5_core] [ 438.994161] mlx5e_delete_flower+0x261/0x390 [mlx5_core] [ 438.994728] tc_setup_cb_destroy+0xb9/0x190 [ 438.995150] fl_hw_destroy_filter+0x94/0xc0 [cls_flower] [ 438.995650] fl_change+0x11a4/0x13c0 [cls_flower] [ 438.996105] tc_new_tfilter+0x347/0xbc0 [ 438.996503] ? ___slab_alloc+0x70/0x8c0 [ 438.996929] rtnetlink_rcv_msg+0xf9/0x3e0 [ 438.997339] ? __netlink_sendskb+0x4c/0x70 [ 438.997751] ? netlink_unicast+0x286/0x2d0 [ 438.998171] ? __pfx_rtnetlink_rcv_msg+0x10/0x10 [ 438.998625] netlink_rcv_skb+0x54/0x100 [ 438.999020] netlink_unicast+0x203/0x2d0 [ 438.999421] netlink_sendmsg+0x1e4/0x420 [ 438.999820] __sock_sendmsg+0xa1/0xb0 [ 439.000203] ____sys_sendmsg+0x207/0x2a0 [ 439.000600] ? copy_msghdr_from_user+0x6d/0xa0 [ 439.001072] ___sys_sendmsg+0x80/0xc0 [ 439.001459] ? ___sys_recvmsg+0x8b/0xc0 [ 439.001848] ? generic_update_time+0x4d/0x60 [ 439.002282] __sys_sendmsg+0x51/0x90 [ 439.002658] do_syscall_64+0x50/0x110 [ 439.003040] entry_SYSCALL_64_after_hwframe+0x76/0x7e Fixes: 718ce4d ("net/mlx5: Consolidate update FTE for all removal changes") Fixes: cefc235 ("net/mlx5: Fix FTE cleanup") Signed-off-by: Mark Bloch <mbloch@nvidia.com> Reviewed-by: Maor Gottlieb <maorg@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107183527.676877-4-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit a848c29 ] On the node of an NFS client, some files saved in the mountpoint of the NFS server were copied to another location of the same NFS server. Accidentally, the nfs42_complete_copies() got a NULL-pointer dereference crash with the following syslog: [232064.838881] NFSv4: state recovery failed for open file nfs/pvc-12b5200d-cd0f-46a3-b9f0-af8f4fe0ef64.qcow2, error = -116 [232064.839360] NFSv4: state recovery failed for open file nfs/pvc-12b5200d-cd0f-46a3-b9f0-af8f4fe0ef64.qcow2, error = -116 [232066.588183] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000058 [232066.588586] Mem abort info: [232066.588701] ESR = 0x0000000096000007 [232066.588862] EC = 0x25: DABT (current EL), IL = 32 bits [232066.589084] SET = 0, FnV = 0 [232066.589216] EA = 0, S1PTW = 0 [232066.589340] FSC = 0x07: level 3 translation fault [232066.589559] Data abort info: [232066.589683] ISV = 0, ISS = 0x00000007 [232066.589842] CM = 0, WnR = 0 [232066.589967] user pgtable: 64k pages, 48-bit VAs, pgdp=00002000956ff400 [232066.590231] [0000000000000058] pgd=08001100ae100003, p4d=08001100ae100003, pud=08001100ae100003, pmd=08001100b3c00003, pte=0000000000000000 [232066.590757] Internal error: Oops: 96000007 [#1] SMP [232066.590958] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs ocfs2_dlmfs ocfs2_stack_o2cb ocfs2_dlm vhost_net vhost vhost_iotlb tap tun ipt_rpfilter xt_multiport ip_set_hash_ip ip_set_hash_net xfrm_interface xfrm6_tunnel tunnel4 tunnel6 esp4 ah4 wireguard libcurve25519_generic veth xt_addrtype xt_set nf_conntrack_netlink ip_set_hash_ipportnet ip_set_hash_ipportip ip_set_bitmap_port ip_set_hash_ipport dummy ip_set ip_vs_sh ip_vs_wrr ip_vs_rr ip_vs iptable_filter sch_ingress nfnetlink_cttimeout vport_gre ip_gre ip_tunnel gre vport_geneve geneve vport_vxlan vxlan ip6_udp_tunnel udp_tunnel openvswitch nf_conncount dm_round_robin dm_service_time dm_multipath xt_nat xt_MASQUERADE nft_chain_nat nf_nat xt_mark xt_conntrack xt_comment nft_compat nft_counter nf_tables nfnetlink ocfs2 ocfs2_nodemanager ocfs2_stackglue iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi ipmi_ssif nbd overlay 8021q garp mrp bonding tls rfkill sunrpc ext4 mbcache jbd2 [232066.591052] vfat fat cas_cache cas_disk ses enclosure scsi_transport_sas sg acpi_ipmi ipmi_si ipmi_devintf ipmi_msghandler ip_tables vfio_pci vfio_pci_core vfio_virqfd vfio_iommu_type1 vfio dm_mirror dm_region_hash dm_log dm_mod nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter bridge stp llc fuse xfs libcrc32c ast drm_vram_helper qla2xxx drm_kms_helper syscopyarea crct10dif_ce sysfillrect ghash_ce sysimgblt sha2_ce fb_sys_fops cec sha256_arm64 sha1_ce drm_ttm_helper ttm nvme_fc igb sbsa_gwdt nvme_fabrics drm nvme_core i2c_algo_bit i40e scsi_transport_fc megaraid_sas aes_neon_bs [232066.596953] CPU: 6 PID: 4124696 Comm: 10.253.166.125- Kdump: loaded Not tainted 5.15.131-9.cl9_ocfs2.aarch64 #1 [232066.597356] Hardware name: Great Wall .\x93\x8e...RF6260 V5/GWMSSE2GL1T, BIOS T656FBE_V3.0.18 2024-01-06 [232066.597721] pstate: 20400009 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [232066.598034] pc : nfs4_reclaim_open_state+0x220/0x800 [nfsv4] [232066.598327] lr : nfs4_reclaim_open_state+0x12c/0x800 [nfsv4] [232066.598595] sp : ffff8000f568fc70 [232066.598731] x29: ffff8000f568fc70 x28: 0000000000001000 x27: ffff21003db33000 [232066.599030] x26: ffff800005521ae0 x25: ffff0100f98fa3f0 x24: 0000000000000001 [232066.599319] x23: ffff800009920008 x22: ffff21003db33040 x21: ffff21003db33050 [232066.599628] x20: ffff410172fe9e40 x19: ffff410172fe9e00 x18: 0000000000000000 [232066.599914] x17: 0000000000000000 x16: 0000000000000004 x15: 0000000000000000 [232066.600195] x14: 0000000000000000 x13: ffff800008e685a8 x12: 00000000eac0c6e6 [232066.600498] x11: 0000000000000000 x10: 0000000000000008 x9 : ffff8000054e5828 [232066.600784] x8 : 00000000ffffffbf x7 : 0000000000000001 x6 : 000000000a9eb14a [232066.601062] x5 : 0000000000000000 x4 : ffff70ff8a14a800 x3 : 0000000000000058 [232066.601348] x2 : 0000000000000001 x1 : 54dce46366daa6c6 x0 : 0000000000000000 [232066.601636] Call trace: [232066.601749] nfs4_reclaim_open_state+0x220/0x800 [nfsv4] [232066.601998] nfs4_do_reclaim+0x1b8/0x28c [nfsv4] [232066.602218] nfs4_state_manager+0x928/0x10f0 [nfsv4] [232066.602455] nfs4_run_state_manager+0x78/0x1b0 [nfsv4] [232066.602690] kthread+0x110/0x114 [232066.602830] ret_from_fork+0x10/0x20 [232066.602985] Code: 1400000d f9403f20 f9402e61 91016003 (f9402c00) [232066.603284] SMP: stopping secondary CPUs [232066.606936] Starting crashdump kernel... [232066.607146] Bye! Analysing the vmcore, we know that nfs4_copy_state listed by destination nfs_server->ss_copies was added by the field copies in handle_async_copy(), and we found a waiting copy process with the stack as: PID: 3511963 TASK: ffff710028b47e00 CPU: 0 COMMAND: "cp" #0 [ffff8001116ef740] __switch_to at ffff8000081b92f4 #1 [ffff8001116ef760] __schedule at ffff800008dd0650 #2 [ffff8001116ef7c0] schedule at ffff800008dd0a00 #3 [ffff8001116ef7e0] schedule_timeout at ffff800008dd6aa0 #4 [ffff8001116ef860] __wait_for_common at ffff800008dd166c #5 [ffff8001116ef8e0] wait_for_completion_interruptible at ffff800008dd1898 #6 [ffff8001116ef8f0] handle_async_copy at ffff8000055142f4 [nfsv4] #7 [ffff8001116ef970] _nfs42_proc_copy at ffff8000055147c8 [nfsv4] #8 [ffff8001116efa80] nfs42_proc_copy at ffff800005514cf0 [nfsv4] #9 [ffff8001116efc50] __nfs4_copy_file_range.constprop.0 at ffff8000054ed694 [nfsv4] The NULL-pointer dereference was due to nfs42_complete_copies() listed the nfs_server->ss_copies by the field ss_copies of nfs4_copy_state. So the nfs4_copy_state address ffff0100f98fa3f0 was offset by 0x10 and the data accessed through this pointer was also incorrect. Generally, the ordered list nfs4_state_owner->so_states indicate open(O_RDWR) or open(O_WRITE) states are reclaimed firstly by nfs4_reclaim_open_state(). When destination state reclaim is failed with NFS_STATE_RECOVERY_FAILED and copies are not deleted in nfs_server->ss_copies, the source state may be passed to the nfs42_complete_copies() process earlier, resulting in this crash scene finally. To solve this issue, we add a list_head nfs_server->ss_src_copies for a server-to-server copy specially. Fixes: 0e65a32 ("NFS: handle source server reboot") Signed-off-by: Yanjun Zhang <zhangyanjun@cestc.cn> Reviewed-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 9ca3144 ] The referenced commits introduced a two-step process for deleting FTEs: - Lock the FTE, delete it from hardware, set the hardware deletion function to NULL and unlock the FTE. - Lock the parent flow group, delete the software copy of the FTE, and remove it from the xarray. However, this approach encounters a race condition if a rule with the same match value is added simultaneously. In this scenario, fs_core may set the hardware deletion function to NULL prematurely, causing a panic during subsequent rule deletions. To prevent this, ensure the active flag of the FTE is checked under a lock, which will prevent the fs_core layer from attaching a new steering rule to an FTE that is in the process of deletion. [ 438.967589] MOSHE: 2496 mlx5_del_flow_rules del_hw_func [ 438.968205] ------------[ cut here ]------------ [ 438.968654] refcount_t: decrement hit 0; leaking memory. [ 438.969249] WARNING: CPU: 0 PID: 8957 at lib/refcount.c:31 refcount_warn_saturate+0xfb/0x110 [ 438.970054] Modules linked in: act_mirred cls_flower act_gact sch_ingress openvswitch nsh mlx5_vdpa vringh vhost_iotlb vdpa mlx5_ib mlx5_core xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat br_netfilter rpcsec_gss_krb5 auth_rpcgss oid_registry overlay rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi ib_umad rdma_cm ib_ipoib iw_cm ib_cm ib_uverbs ib_core zram zsmalloc fuse [last unloaded: cls_flower] [ 438.973288] CPU: 0 UID: 0 PID: 8957 Comm: tc Not tainted 6.12.0-rc1+ #8 [ 438.973888] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 438.974874] RIP: 0010:refcount_warn_saturate+0xfb/0x110 [ 438.975363] Code: 40 66 3b 82 c6 05 16 e9 4d 01 01 e8 1f 7c a0 ff 0f 0b c3 cc cc cc cc 48 c7 c7 10 66 3b 82 c6 05 fd e8 4d 01 01 e8 05 7c a0 ff <0f> 0b c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 90 [ 438.976947] RSP: 0018:ffff888124a53610 EFLAGS: 00010286 [ 438.977446] RAX: 0000000000000000 RBX: ffff888119d56de0 RCX: 0000000000000000 [ 438.978090] RDX: ffff88852c828700 RSI: ffff88852c81b3c0 RDI: ffff88852c81b3c0 [ 438.978721] RBP: ffff888120fa0e88 R08: 0000000000000000 R09: ffff888124a534b0 [ 438.979353] R10: 0000000000000001 R11: 0000000000000001 R12: ffff888119d56de0 [ 438.979979] R13: ffff888120fa0ec0 R14: ffff888120fa0ee8 R15: ffff888119d56de0 [ 438.980607] FS: 00007fe6dcc0f800(0000) GS:ffff88852c800000(0000) knlGS:0000000000000000 [ 438.983984] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 438.984544] CR2: 00000000004275e0 CR3: 0000000186982001 CR4: 0000000000372eb0 [ 438.985205] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 438.985842] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 438.986507] Call Trace: [ 438.986799] <TASK> [ 438.987070] ? __warn+0x7d/0x110 [ 438.987426] ? refcount_warn_saturate+0xfb/0x110 [ 438.987877] ? report_bug+0x17d/0x190 [ 438.988261] ? prb_read_valid+0x17/0x20 [ 438.988659] ? handle_bug+0x53/0x90 [ 438.989054] ? exc_invalid_op+0x14/0x70 [ 438.989458] ? asm_exc_invalid_op+0x16/0x20 [ 438.989883] ? refcount_warn_saturate+0xfb/0x110 [ 438.990348] mlx5_del_flow_rules+0x2f7/0x340 [mlx5_core] [ 438.990932] __mlx5_eswitch_del_rule+0x49/0x170 [mlx5_core] [ 438.991519] ? mlx5_lag_is_sriov+0x3c/0x50 [mlx5_core] [ 438.992054] ? xas_load+0x9/0xb0 [ 438.992407] mlx5e_tc_rule_unoffload+0x45/0xe0 [mlx5_core] [ 438.993037] mlx5e_tc_del_fdb_flow+0x2a6/0x2e0 [mlx5_core] [ 438.993623] mlx5e_flow_put+0x29/0x60 [mlx5_core] [ 438.994161] mlx5e_delete_flower+0x261/0x390 [mlx5_core] [ 438.994728] tc_setup_cb_destroy+0xb9/0x190 [ 438.995150] fl_hw_destroy_filter+0x94/0xc0 [cls_flower] [ 438.995650] fl_change+0x11a4/0x13c0 [cls_flower] [ 438.996105] tc_new_tfilter+0x347/0xbc0 [ 438.996503] ? ___slab_alloc+0x70/0x8c0 [ 438.996929] rtnetlink_rcv_msg+0xf9/0x3e0 [ 438.997339] ? __netlink_sendskb+0x4c/0x70 [ 438.997751] ? netlink_unicast+0x286/0x2d0 [ 438.998171] ? __pfx_rtnetlink_rcv_msg+0x10/0x10 [ 438.998625] netlink_rcv_skb+0x54/0x100 [ 438.999020] netlink_unicast+0x203/0x2d0 [ 438.999421] netlink_sendmsg+0x1e4/0x420 [ 438.999820] __sock_sendmsg+0xa1/0xb0 [ 439.000203] ____sys_sendmsg+0x207/0x2a0 [ 439.000600] ? copy_msghdr_from_user+0x6d/0xa0 [ 439.001072] ___sys_sendmsg+0x80/0xc0 [ 439.001459] ? ___sys_recvmsg+0x8b/0xc0 [ 439.001848] ? generic_update_time+0x4d/0x60 [ 439.002282] __sys_sendmsg+0x51/0x90 [ 439.002658] do_syscall_64+0x50/0x110 [ 439.003040] entry_SYSCALL_64_after_hwframe+0x76/0x7e Fixes: 718ce4d ("net/mlx5: Consolidate update FTE for all removal changes") Fixes: cefc235 ("net/mlx5: Fix FTE cleanup") Signed-off-by: Mark Bloch <mbloch@nvidia.com> Reviewed-by: Maor Gottlieb <maorg@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/20241107183527.676877-4-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>

commit 44d1745 upstream. Use a dedicated mutex to guard kvm_usage_count to fix a potential deadlock on x86 due to a chain of locks and SRCU synchronizations. Translating the below lockdep splat, CPU1 #6 will wait on CPU0 #1, CPU0 #8 will wait on CPU2 #3, and CPU2 #7 will wait on CPU1 #4 (if there's a writer, due to the fairness of r/w semaphores). CPU0 CPU1 CPU2 1 lock(&kvm->slots_lock); 2 lock(&vcpu->mutex); 3 lock(&kvm->srcu); 4 lock(cpu_hotplug_lock); 5 lock(kvm_lock); 6 lock(&kvm->slots_lock); 7 lock(cpu_hotplug_lock); 8 sync(&kvm->srcu); Note, there are likely more potential deadlocks in KVM x86, e.g. the same pattern of taking cpu_hotplug_lock outside of kvm_lock likely exists with __kvmclock_cpufreq_notifier(): cpuhp_cpufreq_online() | -> cpufreq_online() | -> cpufreq_gov_performance_limits() | -> __cpufreq_driver_target() | -> __target_index() | -> cpufreq_freq_transition_begin() | -> cpufreq_notify_transition() | -> ... __kvmclock_cpufreq_notifier() But, actually triggering such deadlocks is beyond rare due to the combination of dependencies and timings involved. E.g. the cpufreq notifier is only used on older CPUs without a constant TSC, mucking with the NX hugepage mitigation while VMs are running is very uncommon, and doing so while also onlining/offlining a CPU (necessary to generate contention on cpu_hotplug_lock) would be even more unusual. The most robust solution to the general cpu_hotplug_lock issue is likely to switch vm_list to be an RCU-protected list, e.g. so that x86's cpufreq notifier doesn't to take kvm_lock. For now, settle for fixing the most blatant deadlock, as switching to an RCU-protected list is a much more involved change, but add a comment in locking.rst to call out that care needs to be taken when walking holding kvm_lock and walking vm_list. ====================================================== WARNING: possible circular locking dependency detected 6.10.0-smp--c257535a0c9d-pip torvalds#330 Tainted: G S O ------------------------------------------------------ tee/35048 is trying to acquire lock: ff6a80eced71e0a8 (&kvm->slots_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x179/0x1e0 [kvm] but task is already holding lock: ffffffffc07abb08 (kvm_lock){+.+.}-{3:3}, at: set_nx_huge_pages+0x14a/0x1e0 [kvm] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (kvm_lock){+.+.}-{3:3}: __mutex_lock+0x6a/0xb40 mutex_lock_nested+0x1f/0x30 kvm_dev_ioctl+0x4fb/0xe50 [kvm] __se_sys_ioctl+0x7b/0xd0 __x64_sys_ioctl+0x21/0x30 x64_sys_call+0x15d0/0x2e60 do_syscall_64+0x83/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e -> #2 (cpu_hotplug_lock){++++}-{0:0}: cpus_read_lock+0x2e/0xb0 static_key_slow_inc+0x16/0x30 kvm_lapic_set_base+0x6a/0x1c0 [kvm] kvm_set_apic_base+0x8f/0xe0 [kvm] kvm_set_msr_common+0x9ae/0xf80 [kvm] vmx_set_msr+0xa54/0xbe0 [kvm_intel] __kvm_set_msr+0xb6/0x1a0 [kvm] kvm_arch_vcpu_ioctl+0xeca/0x10c0 [kvm] kvm_vcpu_ioctl+0x485/0x5b0 [kvm] __se_sys_ioctl+0x7b/0xd0 __x64_sys_ioctl+0x21/0x30 x64_sys_call+0x15d0/0x2e60 do_syscall_64+0x83/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e -> #1 (&kvm->srcu){.+.+}-{0:0}: __synchronize_srcu+0x44/0x1a0 synchronize_srcu_expedited+0x21/0x30 kvm_swap_active_memslots+0x110/0x1c0 [kvm] kvm_set_memslot+0x360/0x620 [kvm] __kvm_set_memory_region+0x27b/0x300 [kvm] kvm_vm_ioctl_set_memory_region+0x43/0x60 [kvm] kvm_vm_ioctl+0x295/0x650 [kvm] __se_sys_ioctl+0x7b/0xd0 __x64_sys_ioctl+0x21/0x30 x64_sys_call+0x15d0/0x2e60 do_syscall_64+0x83/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e -> #0 (&kvm->slots_lock){+.+.}-{3:3}: __lock_acquire+0x15ef/0x2e30 lock_acquire+0xe0/0x260 __mutex_lock+0x6a/0xb40 mutex_lock_nested+0x1f/0x30 set_nx_huge_pages+0x179/0x1e0 [kvm] param_attr_store+0x93/0x100 module_attr_store+0x22/0x40 sysfs_kf_write+0x81/0xb0 kernfs_fop_write_iter+0x133/0x1d0 vfs_write+0x28d/0x380 ksys_write+0x70/0xe0 __x64_sys_write+0x1f/0x30 x64_sys_call+0x281b/0x2e60 do_syscall_64+0x83/0x160 entry_SYSCALL_64_after_hwframe+0x76/0x7e Cc: Chao Gao <chao.gao@intel.com> Fixes: 0bf5049 ("KVM: Drop kvm_count_lock and instead protect kvm_usage_count with kvm_lock") Cc: stable@vger.kernel.org Reviewed-by: Kai Huang <kai.huang@intel.com> Acked-by: Kai Huang <kai.huang@intel.com> Tested-by: Farrah Chen <farrah.chen@intel.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-ID: <20240830043600.127750-2-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit ac01c8c upstream. AddressSanitizer found a use-after-free bug in the symbol code which manifested as 'perf top' segfaulting. ==1238389==ERROR: AddressSanitizer: heap-use-after-free on address 0x60b00c48844b at pc 0x5650d8035961 bp 0x7f751aaecc90 sp 0x7f751aaecc80 READ of size 1 at 0x60b00c48844b thread T193 #0 0x5650d8035960 in _sort__sym_cmp util/sort.c:310 #1 0x5650d8043744 in hist_entry__cmp util/hist.c:1286 #2 0x5650d8043951 in hists__findnew_entry util/hist.c:614 #3 0x5650d804568f in __hists__add_entry util/hist.c:754 #4 0x5650d8045bf9 in hists__add_entry util/hist.c:772 #5 0x5650d8045df1 in iter_add_single_normal_entry util/hist.c:997 #6 0x5650d8043326 in hist_entry_iter__add util/hist.c:1242 #7 0x5650d7ceeefe in perf_event__process_sample /home/matt/src/linux/tools/perf/builtin-top.c:845 #8 0x5650d7ceeefe in deliver_event /home/matt/src/linux/tools/perf/builtin-top.c:1208 #9 0x5650d7fdb51b in do_flush util/ordered-events.c:245 #10 0x5650d7fdb51b in __ordered_events__flush util/ordered-events.c:324 #11 0x5650d7ced743 in process_thread /home/matt/src/linux/tools/perf/builtin-top.c:1120 #12 0x7f757ef1f133 in start_thread nptl/pthread_create.c:442 #13 0x7f757ef9f7db in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81 When updating hist maps it's also necessary to update the hist symbol reference because the old one gets freed in map__put(). While this bug was probably introduced with 5c24b67 ("perf tools: Replace map->referenced & maps->removed_maps with map->refcnt"), the symbol objects were leaked until c087e94 ("perf machine: Fix refcount usage when processing PERF_RECORD_KSYMBOL") was merged so the bug was masked. Fixes: c087e94 ("perf machine: Fix refcount usage when processing PERF_RECORD_KSYMBOL") Reported-by: Yunzhao Li <yunzhao@cloudflare.com> Signed-off-by: Matt Fleming (Cloudflare) <matt@readmodwrite.com> Cc: Ian Rogers <irogers@google.com> Cc: kernel-team@cloudflare.com Cc: Namhyung Kim <namhyung@kernel.org> Cc: Riccardo Mancini <rickyman7@gmail.com> Cc: stable@vger.kernel.org # v5.13+ Link: https://lore.kernel.org/r/20240815142212.3834625-1-matt@readmodwrite.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 9af2efe upstream. The fields in the hist_entry are filled on-demand which means they only have meaningful values when relevant sort keys are used. So if neither of 'dso' nor 'sym' sort keys are used, the map/symbols in the hist entry can be garbage. So it shouldn't access it unconditionally. I got a segfault, when I wanted to see cgroup profiles. $ sudo perf record -a --all-cgroups --synth=cgroup true $ sudo perf report -s cgroup Program received signal SIGSEGV, Segmentation fault. 0x00005555557a8d90 in map__dso (map=0x0) at util/map.h:48 48 return RC_CHK_ACCESS(map)->dso; (gdb) bt #0 0x00005555557a8d90 in map__dso (map=0x0) at util/map.h:48 #1 0x00005555557aa39b in map__load (map=0x0) at util/map.c:344 #2 0x00005555557aa592 in map__find_symbol (map=0x0, addr=140736115941088) at util/map.c:385 #3 0x00005555557ef000 in hists__findnew_entry (hists=0x555556039d60, entry=0x7fffffffa4c0, al=0x7fffffffa8c0, sample_self=true) at util/hist.c:644 #4 0x00005555557ef61c in __hists__add_entry (hists=0x555556039d60, al=0x7fffffffa8c0, sym_parent=0x0, bi=0x0, mi=0x0, ki=0x0, block_info=0x0, sample=0x7fffffffaa90, sample_self=true, ops=0x0) at util/hist.c:761 #5 0x00005555557ef71f in hists__add_entry (hists=0x555556039d60, al=0x7fffffffa8c0, sym_parent=0x0, bi=0x0, mi=0x0, ki=0x0, sample=0x7fffffffaa90, sample_self=true) at util/hist.c:779 #6 0x00005555557f00fb in iter_add_single_normal_entry (iter=0x7fffffffa900, al=0x7fffffffa8c0) at util/hist.c:1015 #7 0x00005555557f09a7 in hist_entry_iter__add (iter=0x7fffffffa900, al=0x7fffffffa8c0, max_stack_depth=127, arg=0x7fffffffbce0) at util/hist.c:1260 #8 0x00005555555ba7ce in process_sample_event (tool=0x7fffffffbce0, event=0x7ffff7c14128, sample=0x7fffffffaa90, evsel=0x555556039ad0, machine=0x5555560388e8) at builtin-report.c:334 #9 0x00005555557b30c8 in evlist__deliver_sample (evlist=0x555556039010, tool=0x7fffffffbce0, event=0x7ffff7c14128, sample=0x7fffffffaa90, evsel=0x555556039ad0, machine=0x5555560388e8) at util/session.c:1232 #10 0x00005555557b32bc in machines__deliver_event (machines=0x5555560388e8, evlist=0x555556039010, event=0x7ffff7c14128, sample=0x7fffffffaa90, tool=0x7fffffffbce0, file_offset=110888, file_path=0x555556038ff0 "perf.data") at util/session.c:1271 #11 0x00005555557b3848 in perf_session__deliver_event (session=0x5555560386d0, event=0x7ffff7c14128, tool=0x7fffffffbce0, file_offset=110888, file_path=0x555556038ff0 "perf.data") at util/session.c:1354 #12 0x00005555557affaf in ordered_events__deliver_event (oe=0x555556038e60, event=0x555556135aa0) at util/session.c:132 #13 0x00005555557bb605 in do_flush (oe=0x555556038e60, show_progress=false) at util/ordered-events.c:245 #14 0x00005555557bb95c in __ordered_events__flush (oe=0x555556038e60, how=OE_FLUSH__ROUND, timestamp=0) at util/ordered-events.c:324 #15 0x00005555557bba46 in ordered_events__flush (oe=0x555556038e60, how=OE_FLUSH__ROUND) at util/ordered-events.c:342 #16 0x00005555557b1b3b in perf_event__process_finished_round (tool=0x7fffffffbce0, event=0x7ffff7c15bb8, oe=0x555556038e60) at util/session.c:780 #17 0x00005555557b3b27 in perf_session__process_user_event (session=0x5555560386d0, event=0x7ffff7c15bb8, file_offset=117688, file_path=0x555556038ff0 "perf.data") at util/session.c:1406 As you can see the entry->ms.map was NULL even if he->ms.map has a value. This is because 'sym' sort key is not given, so it cannot assume whether he->ms.sym and entry->ms.sym is the same. I only checked the 'sym' sort key here as it implies 'dso' behavior (so maps are the same). Fixes: ac01c8c ("perf hist: Update hist symbol when updating maps") Signed-off-by: Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Matt Fleming <matt@readmodwrite.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: https://lore.kernel.org/r/20240826221045.1202305-2-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

l0kod added the enhancement New feature or request label Jan 18, 2024

l0kod changed the title ~~Signal control~~ Signals control Jan 18, 2024

l0kod mentioned this issue Jan 18, 2024

Abstract unix socket control #7

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l0kod added the good first issue Good for newcomers label Jan 30, 2024

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l0kod moved this to Ready in Landlock Feb 1, 2024

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l0kod moved this from Ready to In Progress in Landlock Mar 6, 2024

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This was referenced Apr 11, 2024

Restrict use of SYSV message queues #30

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Restrict use of POSIX message queues #29

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l0kod assigned tahifahimi Jul 15, 2024

l0kod moved this from Ready to In review in Landlock Aug 8, 2024

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Signals control #8

Signals control #8

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l0kod commented Dec 4, 2024

Signals control #8

Signals control #8

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