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Seiji Nishikawa 0a2ed70a54 ACPI: PAD: fix crash in exit_round_robin()
The kernel occasionally crashes in cpumask_clear_cpu(), which is called
within exit_round_robin(), because when executing clear_bit(nr, addr) with
nr set to 0xffffffff, the address calculation may cause misalignment within
the memory, leading to access to an invalid memory address.

----------
BUG: unable to handle kernel paging request at ffffffffe0740618
        ...
CPU: 3 PID: 2919323 Comm: acpi_pad/14 Kdump: loaded Tainted: G           OE  X --------- -  - 4.18.0-425.19.2.el8_7.x86_64 #1
        ...
RIP: 0010:power_saving_thread+0x313/0x411 [acpi_pad]
Code: 89 cd 48 89 d3 eb d1 48 c7 c7 55 70 72 c0 e8 64 86 b0 e4 c6 05 0d a1 02 00 01 e9 bc fd ff ff 45 89 e4 42 8b 04 a5 20 82 72 c0 <f0> 48 0f b3 05 f4 9c 01 00 42 c7 04 a5 20 82 72 c0 ff ff ff ff 31
RSP: 0018:ff72a5d51fa77ec8 EFLAGS: 00010202
RAX: 00000000ffffffff RBX: ff462981e5d8cb80 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000246
RBP: ff46297556959d80 R08: 0000000000000382 R09: ff46297c8d0f38d8
R10: 0000000000000000 R11: 0000000000000001 R12: 000000000000000e
R13: 0000000000000000 R14: ffffffffffffffff R15: 000000000000000e
FS:  0000000000000000(0000) GS:ff46297a800c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffe0740618 CR3: 0000007e20410004 CR4: 0000000000771ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 ? acpi_pad_add+0x120/0x120 [acpi_pad]
 kthread+0x10b/0x130
 ? set_kthread_struct+0x50/0x50
 ret_from_fork+0x1f/0x40
        ...
CR2: ffffffffe0740618

crash> dis -lr ffffffffc0726923
        ...
/usr/src/debug/kernel-4.18.0-425.19.2.el8_7/linux-4.18.0-425.19.2.el8_7.x86_64/./include/linux/cpumask.h: 114
0xffffffffc0726918 <power_saving_thread+776>:	mov    %r12d,%r12d
/usr/src/debug/kernel-4.18.0-425.19.2.el8_7/linux-4.18.0-425.19.2.el8_7.x86_64/./include/linux/cpumask.h: 325
0xffffffffc072691b <power_saving_thread+779>:	mov    -0x3f8d7de0(,%r12,4),%eax
/usr/src/debug/kernel-4.18.0-425.19.2.el8_7/linux-4.18.0-425.19.2.el8_7.x86_64/./arch/x86/include/asm/bitops.h: 80
0xffffffffc0726923 <power_saving_thread+787>:	lock btr %rax,0x19cf4(%rip)        # 0xffffffffc0740620 <pad_busy_cpus_bits>

crash> px tsk_in_cpu[14]
$66 = 0xffffffff

crash> px 0xffffffffc072692c+0x19cf4
$99 = 0xffffffffc0740620

crash> sym 0xffffffffc0740620
ffffffffc0740620 (b) pad_busy_cpus_bits [acpi_pad]

crash> px pad_busy_cpus_bits[0]
$42 = 0xfffc0
----------

To fix this, ensure that tsk_in_cpu[tsk_index] != -1 before calling
cpumask_clear_cpu() in exit_round_robin(), just as it is done in
round_robin_cpu().

Signed-off-by: Seiji Nishikawa <snishika@redhat.com>
Link: https://patch.msgid.link/20240825141352.25280-1-snishika@redhat.com
[ rjw: Subject edit, avoid updates to the same value ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2024-08-29 12:59:21 +02:00
arch s390 updates for 6.11-rc5 2024-08-25 12:05:23 +12:00
block block: Read max write zeroes once for __blkdev_issue_write_zeroes() 2024-08-19 09:48:59 -06:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto crypto: testmgr - generate power-of-2 lengths more often 2024-07-13 11:50:28 +12:00
Documentation workqueue: Fixes for v6.11-rc4 2024-08-24 10:35:57 +08:00
drivers ACPI: PAD: fix crash in exit_round_robin() 2024-08-29 12:59:21 +02:00
fs bcachefs fixes for 6.11-rc5, v2 2024-08-25 17:20:48 +12:00
include SCSI fixes on 20240824 2024-08-25 12:00:16 +12:00
init Rust fixes for v6.11 2024-08-16 11:24:06 -07:00
io_uring io_uring/kbuf: sanitize peek buffer setup 2024-08-21 07:16:38 -06:00
ipc sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
kernel cgroup: Fixes for v6.11-rc4 2024-08-24 10:39:18 +08:00
lib bcachefs fixes for 6.11-rc4 2024-08-17 09:46:10 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm 16 hotfixes. All except one are for MM. 10 of these are cc:stable and 2024-08-17 19:50:16 -07:00
net NFS Client Bugfixes for Linux 6.11-rc 2024-08-24 09:03:25 +08:00
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samples treewide: remove unnecessary <linux/version.h> inclusion 2024-08-12 18:36:44 +09:00
scripts Kbuild fixes for v6.11 (2nd) 2024-08-23 07:43:15 +08:00
security KEYS: trusted: dcp: fix leak of blob encryption key 2024-08-15 22:01:14 +03:00
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tools Including fixes from bluetooth and netfilter. 2024-08-23 07:47:01 +08:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: x86: Disallow read-only memslots for SEV-ES and SEV-SNP (and TDX) 2024-08-14 12:28:24 -04:00
.clang-format Docs: Move clang-format from process/ to dev-tools/ 2024-06-26 16:36:00 -06:00
.cocciconfig
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.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
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.rustfmt.toml
COPYING
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Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig
MAINTAINERS SCSI fixes on 20240824 2024-08-25 12:00:16 +12:00
Makefile Linux 6.11-rc5 2024-08-25 19:07:11 +12:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.