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Rebase 4.13-rc6 patches onto 4.13-rc7 #83
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UEFI machines can be booted in Secure Boot mode. Add a EFI_SECURE_BOOT bit that can be passed to efi_enabled() to find out whether secure boot is enabled. This will be used by the SysRq+x handler, registered by the x86 arch, to find out whether secure boot mode is enabled so that it can be disabled. Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org> Signed-off-by: David Howells <dhowells@redhat.com>
Provide a single call to allow kernel code to determine whether the system should be locked down, thereby disallowing various accesses that might allow the running kernel image to be changed including the loading of modules that aren't validly signed with a key we recognise, fiddling with MSR registers and disallowing hibernation, Signed-off-by: David Howells <dhowells@redhat.com>
UEFI Secure Boot provides a mechanism for ensuring that the firmware will only load signed bootloaders and kernels. Certain use cases may also require that all kernel modules also be signed. Add a configuration option that to lock down the kernel - which includes requiring validly signed modules - if the kernel is secure-booted. Signed-off-by: David Howells <dhowells@redhat.com>
If the kernel is locked down, require that all modules have valid signatures that we can verify. Signed-off-by: David Howells <dhowells@redhat.com>
Allowing users to write to address space makes it possible for the kernel to be subverted, avoiding module loading restrictions. Prevent this when the kernel has been locked down. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: David Howells <dhowells@redhat.com>
kexec permits the loading and execution of arbitrary code in ring 0, which is something that lock-down is meant to prevent. It makes sense to disable kexec in this situation. This does not affect kexec_file_load() which can check for a signature on the image to be booted. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: David Howells <dhowells@redhat.com>
Kexec reboot in case secure boot being enabled does not keep the secure boot mode in new kernel, so later one can load unsigned kernel via legacy kexec_load. In this state, the system is missing the protections provided by secure boot. Adding a patch to fix this by retain the secure_boot flag in original kernel. secure_boot flag in boot_params is set in EFI stub, but kexec bypasses the stub. Fixing this issue by copying secure_boot flag across kexec reboot. Signed-off-by: Dave Young <dyoung@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com>
When KEXEC_VERIFY_SIG is not enabled, kernel should not loads image through kexec_file systemcall if securelevel has been set. This code was showed in Matthew's patch but not in git: https://lkml.org/lkml/2015/3/13/778 Cc: Matthew Garrett <mjg59@srcf.ucam.org> Signed-off-by: Lee, Chun-Yi <jlee@suse.com> Signed-off-by: David Howells <dhowells@redhat.com>
There is currently no way to verify the resume image when returning from hibernate. This might compromise the signed modules trust model, so until we can work with signed hibernate images we disable it when the kernel is locked down. Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org> Signed-off-by: David Howells <dhowells@redhat.com>
uswsusp allows a user process to dump and then restore kernel state, which makes it possible to modify the running kernel. Disable this if the kernel is locked down. Signed-off-by: Matthew Garrett <mjg59@srcf.ucam.org> Signed-off-by: David Howells <dhowells@redhat.com>
Any hardware that can potentially generate DMA has to be locked down in order to avoid it being possible for an attacker to modify kernel code, allowing them to circumvent disabled module loading or module signing. Default to paranoid - in future we can potentially relax this for sufficiently IOMMU-isolated devices. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: David Howells <dhowells@redhat.com>
IO port access would permit users to gain access to PCI configuration registers, which in turn (on a lot of hardware) give access to MMIO register space. This would potentially permit root to trigger arbitrary DMA, so lock it down by default. This also implicitly locks down the KDADDIO, KDDELIO, KDENABIO and KDDISABIO console ioctls. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: David Howells <dhowells@redhat.com>
Writing to MSRs should not be allowed if the kernel is locked down, since it could lead to execution of arbitrary code in kernel mode. Based on a patch by Kees Cook. Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: David Howells <dhowells@redhat.com>
We have no way of validating what all of the Asus WMI methods do on a given machine - and there's a risk that some will allow hardware state to be manipulated in such a way that arbitrary code can be executed in the kernel, circumventing module loading restrictions. Prevent that if the kernel is locked down. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: David Howells <dhowells@redhat.com>
custom_method effectively allows arbitrary access to system memory, making it possible for an attacker to circumvent restrictions on module loading. Disable it if the kernel is locked down. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: David Howells <dhowells@redhat.com>
This option allows userspace to pass the RSDP address to the kernel, which makes it possible for a user to circumvent any restrictions imposed on loading modules. Ignore the option when the kernel is locked down. Signed-off-by: Josh Boyer <jwboyer@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com>
From the kernel documentation (initrd_table_override.txt): If the ACPI_INITRD_TABLE_OVERRIDE compile option is true, it is possible to override nearly any ACPI table provided by the BIOS with an instrumented, modified one. When securelevel is set, the kernel should disallow any unauthenticated changes to kernel space. ACPI tables contain code invoked by the kernel, so do not allow ACPI tables to be overridden if the kernel is locked down. Signed-off-by: Linn Crosetto <linn@hpe.com> Signed-off-by: David Howells <dhowells@redhat.com>
ACPI provides an error injection mechanism, EINJ, for debugging and testing the ACPI Platform Error Interface (APEI) and other RAS features. If supported by the firmware, ACPI specification 5.0 and later provide for a way to specify a physical memory address to which to inject the error. Injecting errors through EINJ can produce errors which to the platform are indistinguishable from real hardware errors. This can have undesirable side-effects, such as causing the platform to mark hardware as needing replacement. While it does not provide a method to load unauthenticated privileged code, the effect of these errors may persist across reboots and affect trust in the underlying hardware, so disable error injection through EINJ if the kernel is locked down. Signed-off-by: Linn Crosetto <linn@hpe.com> Signed-off-by: David Howells <dhowells@redhat.com>
… down There are some bpf functions can be used to read kernel memory: bpf_probe_read, bpf_probe_write_user and bpf_trace_printk. These allow private keys in kernel memory (e.g. the hibernation image signing key) to be read by an eBPF program. Prohibit those functions when the kernel is locked down. Signed-off-by: Lee, Chun-Yi <jlee@suse.com> Signed-off-by: David Howells <dhowells@redhat.com>
When the kernel is running in secure boot mode, we lock down the kernel to prevent userspace from modifying the running kernel image. Whilst this includes prohibiting access to things like /dev/mem, it must also prevent access by means of configuring driver modules in such a way as to cause a device to access or modify the kernel image. The eata driver takes a single string parameter that contains a slew of settings, including hardware resource configuration. Prohibit use of the parameter if the kernel is locked down. Suggested-by: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> cc: Dario Ballabio <ballabio_dario@emc.com> cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com> cc: "Martin K. Petersen" <martin.petersen@oracle.com> cc: linux-scsi@vger.kernel.org
Prohibit replacement of the PCMCIA Card Information Structure when the kernel is locked down. Signed-off-by: David Howells <dhowells@redhat.com>
Lock down TIOCSSERIAL as that can be used to change the ioport and irq settings on a serial port. This only appears to be an issue for the serial drivers that use the core serial code. All other drivers seem to either ignore attempts to change port/irq or give an error. Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: David Howells <dhowells@redhat.com>
This enables relocating source and build trees to different roots, provided they stay reachable relative to one another. Useful for builds done within a sandbox where the eventual root is prefixed by some undesirable path component.
Signed-off-by: Geoff Levand <geoff@infradead.org>
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[ Upstream commit 5171b37 ] In order to remove the race caught by syzbot [1], we need to lock the socket before using po->tp_version as this could change under us otherwise. This means lock_sock() and release_sock() must be done by packet_set_ring() callers. [1] : BUG: KMSAN: uninit-value in packet_set_ring+0x1254/0x3870 net/packet/af_packet.c:4249 CPU: 0 PID: 20195 Comm: syzkaller707632 Not tainted 4.16.0+ #83 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676 packet_set_ring+0x1254/0x3870 net/packet/af_packet.c:4249 packet_setsockopt+0x12c6/0x5a90 net/packet/af_packet.c:3662 SYSC_setsockopt+0x4b8/0x570 net/socket.c:1849 SyS_setsockopt+0x76/0xa0 net/socket.c:1828 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x449099 RSP: 002b:00007f42b5307ce8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 000000000070003c RCX: 0000000000449099 RDX: 0000000000000005 RSI: 0000000000000107 RDI: 0000000000000003 RBP: 0000000000700038 R08: 000000000000001c R09: 0000000000000000 R10: 00000000200000c0 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000080eecf R14: 00007f42b53089c0 R15: 0000000000000001 Local variable description: ----req_u@packet_setsockopt Variable was created at: packet_setsockopt+0x13f/0x5a90 net/packet/af_packet.c:3612 SYSC_setsockopt+0x4b8/0x570 net/socket.c:1849 Fixes: f6fb8f1 ("af-packet: TPACKET_V3 flexible buffer implementation.") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 7212303 ] syzbot/KMSAN reported an uninit-value in tcp_parse_options() [1] I believe this was caused by a TCP_MD5SIG being set on live flow. This is highly unexpected, since TCP option space is limited. For instance, presence of TCP MD5 option automatically disables TCP TimeStamp option at SYN/SYNACK time, which we can not do once flow has been established. Really, adding/deleting an MD5 key only makes sense on sockets in CLOSE or LISTEN state. [1] BUG: KMSAN: uninit-value in tcp_parse_options+0xd74/0x1a30 net/ipv4/tcp_input.c:3720 CPU: 1 PID: 6177 Comm: syzkaller192004 Not tainted 4.16.0+ #83 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676 tcp_parse_options+0xd74/0x1a30 net/ipv4/tcp_input.c:3720 tcp_fast_parse_options net/ipv4/tcp_input.c:3858 [inline] tcp_validate_incoming+0x4f1/0x2790 net/ipv4/tcp_input.c:5184 tcp_rcv_established+0xf60/0x2bb0 net/ipv4/tcp_input.c:5453 tcp_v4_do_rcv+0x6cd/0xd90 net/ipv4/tcp_ipv4.c:1469 sk_backlog_rcv include/net/sock.h:908 [inline] __release_sock+0x2d6/0x680 net/core/sock.c:2271 release_sock+0x97/0x2a0 net/core/sock.c:2786 tcp_sendmsg+0xd6/0x100 net/ipv4/tcp.c:1464 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] SYSC_sendto+0x6c3/0x7e0 net/socket.c:1747 SyS_sendto+0x8a/0xb0 net/socket.c:1715 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x448fe9 RSP: 002b:00007fd472c64d38 EFLAGS: 00000216 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00000000006e5a30 RCX: 0000000000448fe9 RDX: 000000000000029f RSI: 0000000020a88f88 RDI: 0000000000000004 RBP: 00000000006e5a34 R08: 0000000020e68000 R09: 0000000000000010 R10: 00000000200007fd R11: 0000000000000216 R12: 0000000000000000 R13: 00007fff074899ef R14: 00007fd472c659c0 R15: 0000000000000009 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline] kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321 slab_post_alloc_hook mm/slab.h:445 [inline] slab_alloc_node mm/slub.c:2737 [inline] __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369 __kmalloc_reserve net/core/skbuff.c:138 [inline] __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206 alloc_skb include/linux/skbuff.h:984 [inline] tcp_send_ack+0x18c/0x910 net/ipv4/tcp_output.c:3624 __tcp_ack_snd_check net/ipv4/tcp_input.c:5040 [inline] tcp_ack_snd_check net/ipv4/tcp_input.c:5053 [inline] tcp_rcv_established+0x2103/0x2bb0 net/ipv4/tcp_input.c:5469 tcp_v4_do_rcv+0x6cd/0xd90 net/ipv4/tcp_ipv4.c:1469 sk_backlog_rcv include/net/sock.h:908 [inline] __release_sock+0x2d6/0x680 net/core/sock.c:2271 release_sock+0x97/0x2a0 net/core/sock.c:2786 tcp_sendmsg+0xd6/0x100 net/ipv4/tcp.c:1464 inet_sendmsg+0x48d/0x740 net/ipv4/af_inet.c:764 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] SYSC_sendto+0x6c3/0x7e0 net/socket.c:1747 SyS_sendto+0x8a/0xb0 net/socket.c:1715 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Fixes: cfb6eeb ("[TCP]: MD5 Signature Option (RFC2385) support.") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 7dd07c1 ] Since neigh_dump_table() calls nlmsg_parse() without giving policy constraints, attributes can have arbirary size that we must validate Reported by syzbot/KMSAN : BUG: KMSAN: uninit-value in neigh_master_filtered net/core/neighbour.c:2292 [inline] BUG: KMSAN: uninit-value in neigh_dump_table net/core/neighbour.c:2348 [inline] BUG: KMSAN: uninit-value in neigh_dump_info+0x1af0/0x2250 net/core/neighbour.c:2438 CPU: 1 PID: 3575 Comm: syzkaller268891 Not tainted 4.16.0+ #83 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676 neigh_master_filtered net/core/neighbour.c:2292 [inline] neigh_dump_table net/core/neighbour.c:2348 [inline] neigh_dump_info+0x1af0/0x2250 net/core/neighbour.c:2438 netlink_dump+0x9ad/0x1540 net/netlink/af_netlink.c:2225 __netlink_dump_start+0x1167/0x12a0 net/netlink/af_netlink.c:2322 netlink_dump_start include/linux/netlink.h:214 [inline] rtnetlink_rcv_msg+0x1435/0x1560 net/core/rtnetlink.c:4598 netlink_rcv_skb+0x355/0x5f0 net/netlink/af_netlink.c:2447 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:4653 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline] netlink_unicast+0x1672/0x1750 net/netlink/af_netlink.c:1337 netlink_sendmsg+0x1048/0x1310 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046 __sys_sendmsg net/socket.c:2080 [inline] SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091 SyS_sendmsg+0x54/0x80 net/socket.c:2087 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x43fed9 RSP: 002b:00007ffddbee2798 EFLAGS: 00000213 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fed9 RDX: 0000000000000000 RSI: 0000000020005000 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000004002c8 R11: 0000000000000213 R12: 0000000000401800 R13: 0000000000401890 R14: 0000000000000000 R15: 0000000000000000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline] kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321 slab_post_alloc_hook mm/slab.h:445 [inline] slab_alloc_node mm/slub.c:2737 [inline] __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369 __kmalloc_reserve net/core/skbuff.c:138 [inline] __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206 alloc_skb include/linux/skbuff.h:984 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1183 [inline] netlink_sendmsg+0x9a6/0x1310 net/netlink/af_netlink.c:1875 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046 __sys_sendmsg net/socket.c:2080 [inline] SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091 SyS_sendmsg+0x54/0x80 net/socket.c:2087 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Fixes: 21fdd09 ("net: Add support for filtering neigh dump by master device") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: David Ahern <dsa@cumulusnetworks.com> Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Oct 7, 2019
[ Upstream commit 232219b ] When the kernel is build with lockdep support and the i2c-cht-wc driver is used, the following warning is shown: [ 66.674334] ====================================================== [ 66.674337] WARNING: possible circular locking dependency detected [ 66.674340] 5.3.0-rc4+ #83 Not tainted [ 66.674342] ------------------------------------------------------ [ 66.674345] systemd-udevd/1232 is trying to acquire lock: [ 66.674349] 00000000a74dab07 (intel_soc_pmic_chtwc:167:(&cht_wc_regmap_cfg)->lock){+.+.}, at: regmap_write+0x31/0x70 [ 66.674360] but task is already holding lock: [ 66.674362] 00000000d44a85b7 (i2c_register_adapter){+.+.}, at: i2c_smbus_xfer+0x49/0xf0 [ 66.674370] which lock already depends on the new lock. [ 66.674371] the existing dependency chain (in reverse order) is: [ 66.674374] -> #1 (i2c_register_adapter){+.+.}: [ 66.674381] rt_mutex_lock_nested+0x46/0x60 [ 66.674384] i2c_smbus_xfer+0x49/0xf0 [ 66.674387] i2c_smbus_read_byte_data+0x45/0x70 [ 66.674391] cht_wc_byte_reg_read+0x35/0x50 [ 66.674394] _regmap_read+0x63/0x1a0 [ 66.674396] _regmap_update_bits+0xa8/0xe0 [ 66.674399] regmap_update_bits_base+0x63/0xa0 [ 66.674403] regmap_irq_update_bits.isra.0+0x3b/0x50 [ 66.674406] regmap_add_irq_chip+0x592/0x7a0 [ 66.674409] devm_regmap_add_irq_chip+0x89/0xed [ 66.674412] cht_wc_probe+0x102/0x158 [ 66.674415] i2c_device_probe+0x95/0x250 [ 66.674419] really_probe+0xf3/0x380 [ 66.674422] driver_probe_device+0x59/0xd0 [ 66.674425] device_driver_attach+0x53/0x60 [ 66.674428] __driver_attach+0x92/0x150 [ 66.674431] bus_for_each_dev+0x7d/0xc0 [ 66.674434] bus_add_driver+0x14d/0x1f0 [ 66.674437] driver_register+0x6d/0xb0 [ 66.674440] i2c_register_driver+0x45/0x80 [ 66.674445] do_one_initcall+0x60/0x2f4 [ 66.674450] kernel_init_freeable+0x20d/0x2b4 [ 66.674453] kernel_init+0xa/0x10c [ 66.674457] ret_from_fork+0x3a/0x50 [ 66.674459] -> #0 (intel_soc_pmic_chtwc:167:(&cht_wc_regmap_cfg)->lock){+.+.}: [ 66.674465] __lock_acquire+0xe07/0x1930 [ 66.674468] lock_acquire+0x9d/0x1a0 [ 66.674472] __mutex_lock+0xa8/0x9a0 [ 66.674474] regmap_write+0x31/0x70 [ 66.674480] cht_wc_i2c_adap_smbus_xfer+0x72/0x240 [i2c_cht_wc] [ 66.674483] __i2c_smbus_xfer+0x1a3/0x640 [ 66.674486] i2c_smbus_xfer+0x67/0xf0 [ 66.674489] i2c_smbus_read_byte_data+0x45/0x70 [ 66.674494] bq24190_probe+0x26b/0x410 [bq24190_charger] [ 66.674497] i2c_device_probe+0x189/0x250 [ 66.674500] really_probe+0xf3/0x380 [ 66.674503] driver_probe_device+0x59/0xd0 [ 66.674506] device_driver_attach+0x53/0x60 [ 66.674509] __driver_attach+0x92/0x150 [ 66.674512] bus_for_each_dev+0x7d/0xc0 [ 66.674515] bus_add_driver+0x14d/0x1f0 [ 66.674518] driver_register+0x6d/0xb0 [ 66.674521] i2c_register_driver+0x45/0x80 [ 66.674524] do_one_initcall+0x60/0x2f4 [ 66.674528] do_init_module+0x5c/0x230 [ 66.674531] load_module+0x2707/0x2a20 [ 66.674534] __do_sys_init_module+0x188/0x1b0 [ 66.674537] do_syscall_64+0x5c/0xb0 [ 66.674541] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 66.674543] other info that might help us debug this: [ 66.674545] Possible unsafe locking scenario: [ 66.674547] CPU0 CPU1 [ 66.674548] ---- ---- [ 66.674550] lock(i2c_register_adapter); [ 66.674553] lock(intel_soc_pmic_chtwc:167:(&cht_wc_regmap_cfg)->lock); [ 66.674556] lock(i2c_register_adapter); [ 66.674559] lock(intel_soc_pmic_chtwc:167:(&cht_wc_regmap_cfg)->lock); [ 66.674561] *** DEADLOCK *** The problem is that the CHT Whiskey Cove PMIC's builtin i2c-adapter is itself a part of an i2c-client (the PMIC). This means that transfers done through it take adapter->bus_lock twice, once for the parent i2c-adapter and once for its own bus_lock. Lockdep does not like this nested locking. To make lockdep happy in the case of busses with muxes, the i2c-core's i2c_adapter_lock_bus function calls: rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter)); But i2c_adapter_depth only works when the direct parent of the adapter is another adapter, as it is only meant for muxes. In this case there is an i2c-client and MFD instantiated platform_device in the parent->child chain between the 2 devices. This commit overrides the default i2c_lock_operations, passing a hardcoded depth of 1 to rt_mutex_lock_nested, making lockdep happy. Note that if there were to be a mux attached to the i2c-wc-cht adapter, this would break things again since the i2c-mux code expects the root-adapter to have a locking depth of 0. But the i2c-wc-cht adapter always has only 1 client directly attached in the form of the charger IC paired with the CHT Whiskey Cove PMIC. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Sasha Levin <sashal@kernel.org>
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