| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: btintel_pcie: Allocate memory for driver private data
Fix driver not allocating memory for struct btintel_data which is used
to store internal data. |
| In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: SHAMPO, Fix incorrect page release
Under the following conditions:
1) No skb created yet
2) header_size == 0 (no SHAMPO header)
3) header_index + 1 % MLX5E_SHAMPO_WQ_HEADER_PER_PAGE == 0 (this is the
last page fragment of a SHAMPO header page)
a new skb is formed with a page that is NOT a SHAMPO header page (it
is a regular data page). Further down in the same function
(mlx5e_handle_rx_cqe_mpwrq_shampo()), a SHAMPO header page from
header_index is released. This is wrong and it leads to SHAMPO header
pages being released more than once. |
| In the Linux kernel, the following vulnerability has been resolved:
memcg_write_event_control(): fix a user-triggerable oops
we are *not* guaranteed that anything past the terminating NUL
is mapped (let alone initialized with anything sane). |
| In the Linux kernel, the following vulnerability has been resolved:
xfrm: Fix input error path memory access
When there is a misconfiguration of input state slow path
KASAN report error. Fix this error.
west login:
[ 52.987278] eth1: renamed from veth11
[ 53.078814] eth1: renamed from veth21
[ 53.181355] eth1: renamed from veth31
[ 54.921702] ==================================================================
[ 54.922602] BUG: KASAN: wild-memory-access in xfrmi_rcv_cb+0x2d/0x295
[ 54.923393] Read of size 8 at addr 6b6b6b6b00000000 by task ping/512
[ 54.924169]
[ 54.924386] CPU: 0 PID: 512 Comm: ping Not tainted 6.9.0-08574-gcd29a4313a1b #25
[ 54.925290] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 54.926401] Call Trace:
[ 54.926731] <IRQ>
[ 54.927009] dump_stack_lvl+0x2a/0x3b
[ 54.927478] kasan_report+0x84/0xa6
[ 54.927930] ? xfrmi_rcv_cb+0x2d/0x295
[ 54.928410] xfrmi_rcv_cb+0x2d/0x295
[ 54.928872] ? xfrm4_rcv_cb+0x3d/0x5e
[ 54.929354] xfrm4_rcv_cb+0x46/0x5e
[ 54.929804] xfrm_rcv_cb+0x7e/0xa1
[ 54.930240] xfrm_input+0x1b3a/0x1b96
[ 54.930715] ? xfrm_offload+0x41/0x41
[ 54.931182] ? raw_rcv+0x292/0x292
[ 54.931617] ? nf_conntrack_confirm+0xa2/0xa2
[ 54.932158] ? skb_sec_path+0xd/0x3f
[ 54.932610] ? xfrmi_input+0x90/0xce
[ 54.933066] xfrm4_esp_rcv+0x33/0x54
[ 54.933521] ip_protocol_deliver_rcu+0xd7/0x1b2
[ 54.934089] ip_local_deliver_finish+0x110/0x120
[ 54.934659] ? ip_protocol_deliver_rcu+0x1b2/0x1b2
[ 54.935248] NF_HOOK.constprop.0+0xf8/0x138
[ 54.935767] ? ip_sublist_rcv_finish+0x68/0x68
[ 54.936317] ? secure_tcpv6_ts_off+0x23/0x168
[ 54.936859] ? ip_protocol_deliver_rcu+0x1b2/0x1b2
[ 54.937454] ? __xfrm_policy_check2.constprop.0+0x18d/0x18d
[ 54.938135] NF_HOOK.constprop.0+0xf8/0x138
[ 54.938663] ? ip_sublist_rcv_finish+0x68/0x68
[ 54.939220] ? __xfrm_policy_check2.constprop.0+0x18d/0x18d
[ 54.939904] ? ip_local_deliver_finish+0x120/0x120
[ 54.940497] __netif_receive_skb_one_core+0xc9/0x107
[ 54.941121] ? __netif_receive_skb_list_core+0x1c2/0x1c2
[ 54.941771] ? blk_mq_start_stopped_hw_queues+0xc7/0xf9
[ 54.942413] ? blk_mq_start_stopped_hw_queue+0x38/0x38
[ 54.943044] ? virtqueue_get_buf_ctx+0x295/0x46b
[ 54.943618] process_backlog+0xb3/0x187
[ 54.944102] __napi_poll.constprop.0+0x57/0x1a7
[ 54.944669] net_rx_action+0x1cb/0x380
[ 54.945150] ? __napi_poll.constprop.0+0x1a7/0x1a7
[ 54.945744] ? vring_new_virtqueue+0x17a/0x17a
[ 54.946300] ? note_interrupt+0x2cd/0x367
[ 54.946805] handle_softirqs+0x13c/0x2c9
[ 54.947300] do_softirq+0x5f/0x7d
[ 54.947727] </IRQ>
[ 54.948014] <TASK>
[ 54.948300] __local_bh_enable_ip+0x48/0x62
[ 54.948832] __neigh_event_send+0x3fd/0x4ca
[ 54.949361] neigh_resolve_output+0x1e/0x210
[ 54.949896] ip_finish_output2+0x4bf/0x4f0
[ 54.950410] ? __ip_finish_output+0x171/0x1b8
[ 54.950956] ip_send_skb+0x25/0x57
[ 54.951390] raw_sendmsg+0xf95/0x10c0
[ 54.951850] ? check_new_pages+0x45/0x71
[ 54.952343] ? raw_hash_sk+0x21b/0x21b
[ 54.952815] ? kernel_init_pages+0x42/0x51
[ 54.953337] ? prep_new_page+0x44/0x51
[ 54.953811] ? get_page_from_freelist+0x72b/0x915
[ 54.954390] ? signal_pending_state+0x77/0x77
[ 54.954936] ? preempt_count_sub+0x14/0xb3
[ 54.955450] ? __might_resched+0x8a/0x240
[ 54.955951] ? __might_sleep+0x25/0xa0
[ 54.956424] ? first_zones_zonelist+0x2c/0x43
[ 54.956977] ? __rcu_read_lock+0x2d/0x3a
[ 54.957476] ? __pte_offset_map+0x32/0xa4
[ 54.957980] ? __might_resched+0x8a/0x240
[ 54.958483] ? __might_sleep+0x25/0xa0
[ 54.958963] ? inet_send_prepare+0x54/0x54
[ 54.959478] ? sock_sendmsg_nosec+0x42/0x6c
[ 54.960000] sock_sendmsg_nosec+0x42/0x6c
[ 54.960502] __sys_sendto+0x15d/0x1cc
[ 54.960966] ? __x64_sys_getpeername+0x44/0x44
[ 54.961522] ? __handle_mm_fault+0x679/0xae4
[ 54.962068] ? find_vma+0x6b/0x
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
RDMA/hns: Fix soft lockup under heavy CEQE load
CEQEs are handled in interrupt handler currently. This may cause the
CPU core staying in interrupt context too long and lead to soft lockup
under heavy load.
Handle CEQEs in BH workqueue and set an upper limit for the number of
CEQE handled by a single call of work handler. |
| In the Linux kernel, the following vulnerability has been resolved:
landlock: Don't lose track of restrictions on cred_transfer
When a process' cred struct is replaced, this _almost_ always invokes
the cred_prepare LSM hook; but in one special case (when
KEYCTL_SESSION_TO_PARENT updates the parent's credentials), the
cred_transfer LSM hook is used instead. Landlock only implements the
cred_prepare hook, not cred_transfer, so KEYCTL_SESSION_TO_PARENT causes
all information on Landlock restrictions to be lost.
This basically means that a process with the ability to use the fork()
and keyctl() syscalls can get rid of all Landlock restrictions on
itself.
Fix it by adding a cred_transfer hook that does the same thing as the
existing cred_prepare hook. (Implemented by having hook_cred_prepare()
call hook_cred_transfer() so that the two functions are less likely to
accidentally diverge in the future.) |
| In the Linux kernel, the following vulnerability has been resolved:
spi: don't unoptimize message in spi_async()
Calling spi_maybe_unoptimize_message() in spi_async() is wrong because
the message is likely to be in the queue and not transferred yet. This
can corrupt the message while it is being used by the controller driver.
spi_maybe_unoptimize_message() is already called in the correct place
in spi_finalize_current_message() to balance the call to
spi_maybe_optimize_message() in spi_async(). |
| In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: configfs: Prevent OOB read/write in usb_string_copy()
Userspace provided string 's' could trivially have the length zero. Left
unchecked this will firstly result in an OOB read in the form
`if (str[0 - 1] == '\n') followed closely by an OOB write in the form
`str[0 - 1] = '\0'`.
There is already a validating check to catch strings that are too long.
Let's supply an additional check for invalid strings that are too short. |
| In the Linux kernel, the following vulnerability has been resolved:
s390/mm: Add NULL pointer check to crst_table_free() base_crst_free()
crst_table_free() used to work with NULL pointers before the conversion
to ptdescs. Since crst_table_free() can be called with a NULL pointer
(error handling in crst_table_upgrade() add an explicit check.
Also add the same check to base_crst_free() for consistency reasons.
In real life this should not happen, since order two GFP_KERNEL
allocations will not fail, unless FAIL_PAGE_ALLOC is enabled and used. |
| In the Linux kernel, the following vulnerability has been resolved:
filemap: replace pte_offset_map() with pte_offset_map_nolock()
The vmf->ptl in filemap_fault_recheck_pte_none() is still set from
handle_pte_fault(). But at the same time, we did a pte_unmap(vmf->pte).
After a pte_unmap(vmf->pte) unmap and rcu_read_unlock(), the page table
may be racily changed and vmf->ptl maybe fails to protect the actual page
table. Fix this by replacing pte_offset_map() with
pte_offset_map_nolock().
As David said, the PTL pointer might be stale so if we continue to use
it infilemap_fault_recheck_pte_none(), it might trigger UAF. Also, if
the PTL fails, the issue fixed by commit 58f327f2ce80 ("filemap: avoid
unnecessary major faults in filemap_fault()") might reappear. |
| In the Linux kernel, the following vulnerability has been resolved:
cachefiles: add consistency check for copen/cread
This prevents malicious processes from completing random copen/cread
requests and crashing the system. Added checks are listed below:
* Generic, copen can only complete open requests, and cread can only
complete read requests.
* For copen, ondemand_id must not be 0, because this indicates that the
request has not been read by the daemon.
* For cread, the object corresponding to fd and req should be the same. |
| In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix kernel bug on rename operation of broken directory
Syzbot reported that in rename directory operation on broken directory on
nilfs2, __block_write_begin_int() called to prepare block write may fail
BUG_ON check for access exceeding the folio/page size.
This is because nilfs_dotdot(), which gets parent directory reference
entry ("..") of the directory to be moved or renamed, does not check
consistency enough, and may return location exceeding folio/page size for
broken directories.
Fix this issue by checking required directory entries ("." and "..") in
the first chunk of the directory in nilfs_dotdot(). |
| In the Linux kernel, the following vulnerability has been resolved:
mm: vmalloc: check if a hash-index is in cpu_possible_mask
The problem is that there are systems where cpu_possible_mask has gaps
between set CPUs, for example SPARC. In this scenario addr_to_vb_xa()
hash function can return an index which accesses to not-possible and not
setup CPU area using per_cpu() macro. This results in an oops on SPARC.
A per-cpu vmap_block_queue is also used as hash table, incorrectly
assuming the cpu_possible_mask has no gaps. Fix it by adjusting an index
to a next possible CPU. |
| In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu: change vm->task_info handling
This patch changes the handling and lifecycle of vm->task_info object.
The major changes are:
- vm->task_info is a dynamically allocated ptr now, and its uasge is
reference counted.
- introducing two new helper funcs for task_info lifecycle management
- amdgpu_vm_get_task_info: reference counts up task_info before
returning this info
- amdgpu_vm_put_task_info: reference counts down task_info
- last put to task_info() frees task_info from the vm.
This patch also does logistical changes required for existing usage
of vm->task_info.
V2: Do not block all the prints when task_info not found (Felix)
V3: Fixed review comments from Felix
- Fix wrong indentation
- No debug message for -ENOMEM
- Add NULL check for task_info
- Do not duplicate the debug messages (ti vs no ti)
- Get first reference of task_info in vm_init(), put last
in vm_fini()
V4: Fixed review comments from Felix
- fix double reference increment in create_task_info
- change amdgpu_vm_get_task_info_pasid
- additional changes in amdgpu_gem.c while porting |
| In the Linux kernel, the following vulnerability has been resolved:
tcp: avoid too many retransmit packets
If a TCP socket is using TCP_USER_TIMEOUT, and the other peer
retracted its window to zero, tcp_retransmit_timer() can
retransmit a packet every two jiffies (2 ms for HZ=1000),
for about 4 minutes after TCP_USER_TIMEOUT has 'expired'.
The fix is to make sure tcp_rtx_probe0_timed_out() takes
icsk->icsk_user_timeout into account.
Before blamed commit, the socket would not timeout after
icsk->icsk_user_timeout, but would use standard exponential
backoff for the retransmits.
Also worth noting that before commit e89688e3e978 ("net: tcp:
fix unexcepted socket die when snd_wnd is 0"), the issue
would last 2 minutes instead of 4. |
| In the Linux kernel, the following vulnerability has been resolved:
net: ena: Add validation for completion descriptors consistency
Validate that `first` flag is set only for the first
descriptor in multi-buffer packets.
In case of an invalid descriptor, a reset will occur.
A new reset reason for RX data corruption has been added. |
| In the Linux kernel, the following vulnerability has been resolved:
mm: shmem: fix getting incorrect lruvec when replacing a shmem folio
When testing shmem swapin, I encountered the warning below on my machine.
The reason is that replacing an old shmem folio with a new one causes
mem_cgroup_migrate() to clear the old folio's memcg data. As a result,
the old folio cannot get the correct memcg's lruvec needed to remove
itself from the LRU list when it is being freed. This could lead to
possible serious problems, such as LRU list crashes due to holding the
wrong LRU lock, and incorrect LRU statistics.
To fix this issue, we can fallback to use the mem_cgroup_replace_folio()
to replace the old shmem folio.
[ 5241.100311] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5d9960
[ 5241.100317] head: order:4 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
[ 5241.100319] flags: 0x17fffe0000040068(uptodate|lru|head|swapbacked|node=0|zone=2|lastcpupid=0x3ffff)
[ 5241.100323] raw: 17fffe0000040068 fffffdffd6687948 fffffdffd69ae008 0000000000000000
[ 5241.100325] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[ 5241.100326] head: 17fffe0000040068 fffffdffd6687948 fffffdffd69ae008 0000000000000000
[ 5241.100327] head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[ 5241.100328] head: 17fffe0000000204 fffffdffd6665801 ffffffffffffffff 0000000000000000
[ 5241.100329] head: 0000000a00000010 0000000000000000 00000000ffffffff 0000000000000000
[ 5241.100330] page dumped because: VM_WARN_ON_ONCE_FOLIO(!memcg && !mem_cgroup_disabled())
[ 5241.100338] ------------[ cut here ]------------
[ 5241.100339] WARNING: CPU: 19 PID: 78402 at include/linux/memcontrol.h:775 folio_lruvec_lock_irqsave+0x140/0x150
[...]
[ 5241.100374] pc : folio_lruvec_lock_irqsave+0x140/0x150
[ 5241.100375] lr : folio_lruvec_lock_irqsave+0x138/0x150
[ 5241.100376] sp : ffff80008b38b930
[...]
[ 5241.100398] Call trace:
[ 5241.100399] folio_lruvec_lock_irqsave+0x140/0x150
[ 5241.100401] __page_cache_release+0x90/0x300
[ 5241.100404] __folio_put+0x50/0x108
[ 5241.100406] shmem_replace_folio+0x1b4/0x240
[ 5241.100409] shmem_swapin_folio+0x314/0x528
[ 5241.100411] shmem_get_folio_gfp+0x3b4/0x930
[ 5241.100412] shmem_fault+0x74/0x160
[ 5241.100414] __do_fault+0x40/0x218
[ 5241.100417] do_shared_fault+0x34/0x1b0
[ 5241.100419] do_fault+0x40/0x168
[ 5241.100420] handle_pte_fault+0x80/0x228
[ 5241.100422] __handle_mm_fault+0x1c4/0x440
[ 5241.100424] handle_mm_fault+0x60/0x1f0
[ 5241.100426] do_page_fault+0x120/0x488
[ 5241.100429] do_translation_fault+0x4c/0x68
[ 5241.100431] do_mem_abort+0x48/0xa0
[ 5241.100434] el0_da+0x38/0xc0
[ 5241.100436] el0t_64_sync_handler+0x68/0xc0
[ 5241.100437] el0t_64_sync+0x14c/0x150
[ 5241.100439] ---[ end trace 0000000000000000 ]---
[baolin.wang@linux.alibaba.com: remove less helpful comments, per Matthew] |
| In the Linux kernel, the following vulnerability has been resolved:
drm/i915/dpt: Make DPT object unshrinkable
In some scenarios, the DPT object gets shrunk but
the actual framebuffer did not and thus its still
there on the DPT's vm->bound_list. Then it tries to
rewrite the PTEs via a stale CPU mapping. This causes panic.
[vsyrjala: Add TODO comment]
(cherry picked from commit 51064d471c53dcc8eddd2333c3f1c1d9131ba36c) |
| In the Linux kernel, the following vulnerability has been resolved:
vmxnet3: disable rx data ring on dma allocation failure
When vmxnet3_rq_create() fails to allocate memory for rq->data_ring.base,
the subsequent call to vmxnet3_rq_destroy_all_rxdataring does not reset
rq->data_ring.desc_size for the data ring that failed, which presumably
causes the hypervisor to reference it on packet reception.
To fix this bug, rq->data_ring.desc_size needs to be set to 0 to tell
the hypervisor to disable this feature.
[ 95.436876] kernel BUG at net/core/skbuff.c:207!
[ 95.439074] invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
[ 95.440411] CPU: 7 PID: 0 Comm: swapper/7 Not tainted 6.9.3-dirty #1
[ 95.441558] Hardware name: VMware, Inc. VMware Virtual
Platform/440BX Desktop Reference Platform, BIOS 6.00 12/12/2018
[ 95.443481] RIP: 0010:skb_panic+0x4d/0x4f
[ 95.444404] Code: 4f 70 50 8b 87 c0 00 00 00 50 8b 87 bc 00 00 00 50
ff b7 d0 00 00 00 4c 8b 8f c8 00 00 00 48 c7 c7 68 e8 be 9f e8 63 58 f9
ff <0f> 0b 48 8b 14 24 48 c7 c1 d0 73 65 9f e8 a1 ff ff ff 48 8b 14 24
[ 95.447684] RSP: 0018:ffffa13340274dd0 EFLAGS: 00010246
[ 95.448762] RAX: 0000000000000089 RBX: ffff8fbbc72b02d0 RCX: 000000000000083f
[ 95.450148] RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000083f
[ 95.451520] RBP: 000000000000002d R08: 0000000000000000 R09: ffffa13340274c60
[ 95.452886] R10: ffffffffa04ed468 R11: 0000000000000002 R12: 0000000000000000
[ 95.454293] R13: ffff8fbbdab3c2d0 R14: ffff8fbbdbd829e0 R15: ffff8fbbdbd809e0
[ 95.455682] FS: 0000000000000000(0000) GS:ffff8fbeefd80000(0000) knlGS:0000000000000000
[ 95.457178] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 95.458340] CR2: 00007fd0d1f650c8 CR3: 0000000115f28000 CR4: 00000000000406f0
[ 95.459791] Call Trace:
[ 95.460515] <IRQ>
[ 95.461180] ? __die_body.cold+0x19/0x27
[ 95.462150] ? die+0x2e/0x50
[ 95.462976] ? do_trap+0xca/0x110
[ 95.463973] ? do_error_trap+0x6a/0x90
[ 95.464966] ? skb_panic+0x4d/0x4f
[ 95.465901] ? exc_invalid_op+0x50/0x70
[ 95.466849] ? skb_panic+0x4d/0x4f
[ 95.467718] ? asm_exc_invalid_op+0x1a/0x20
[ 95.468758] ? skb_panic+0x4d/0x4f
[ 95.469655] skb_put.cold+0x10/0x10
[ 95.470573] vmxnet3_rq_rx_complete+0x862/0x11e0 [vmxnet3]
[ 95.471853] vmxnet3_poll_rx_only+0x36/0xb0 [vmxnet3]
[ 95.473185] __napi_poll+0x2b/0x160
[ 95.474145] net_rx_action+0x2c6/0x3b0
[ 95.475115] handle_softirqs+0xe7/0x2a0
[ 95.476122] __irq_exit_rcu+0x97/0xb0
[ 95.477109] common_interrupt+0x85/0xa0
[ 95.478102] </IRQ>
[ 95.478846] <TASK>
[ 95.479603] asm_common_interrupt+0x26/0x40
[ 95.480657] RIP: 0010:pv_native_safe_halt+0xf/0x20
[ 95.481801] Code: 22 d7 e9 54 87 01 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d 93 ba 3b 00 fb f4 <e9> 2c 87 01 00 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90
[ 95.485563] RSP: 0018:ffffa133400ffe58 EFLAGS: 00000246
[ 95.486882] RAX: 0000000000004000 RBX: ffff8fbbc1d14064 RCX: 0000000000000000
[ 95.488477] RDX: ffff8fbeefd80000 RSI: ffff8fbbc1d14000 RDI: 0000000000000001
[ 95.490067] RBP: ffff8fbbc1d14064 R08: ffffffffa0652260 R09: 00000000000010d3
[ 95.491683] R10: 0000000000000018 R11: ffff8fbeefdb4764 R12: ffffffffa0652260
[ 95.493389] R13: ffffffffa06522e0 R14: 0000000000000001 R15: 0000000000000000
[ 95.495035] acpi_safe_halt+0x14/0x20
[ 95.496127] acpi_idle_do_entry+0x2f/0x50
[ 95.497221] acpi_idle_enter+0x7f/0xd0
[ 95.498272] cpuidle_enter_state+0x81/0x420
[ 95.499375] cpuidle_enter+0x2d/0x40
[ 95.500400] do_idle+0x1e5/0x240
[ 95.501385] cpu_startup_entry+0x29/0x30
[ 95.502422] start_secondary+0x11c/0x140
[ 95.503454] common_startup_64+0x13e/0x141
[ 95.504466] </TASK>
[ 95.505197] Modules linked in: nft_fib_inet nft_fib_ipv4
nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6
nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ip
---truncated--- |
| In the Linux kernel, the following vulnerability has been resolved:
parisc: Try to fix random segmentation faults in package builds
PA-RISC systems with PA8800 and PA8900 processors have had problems
with random segmentation faults for many years. Systems with earlier
processors are much more stable.
Systems with PA8800 and PA8900 processors have a large L2 cache which
needs per page flushing for decent performance when a large range is
flushed. The combined cache in these systems is also more sensitive to
non-equivalent aliases than the caches in earlier systems.
The majority of random segmentation faults that I have looked at
appear to be memory corruption in memory allocated using mmap and
malloc.
My first attempt at fixing the random faults didn't work. On
reviewing the cache code, I realized that there were two issues
which the existing code didn't handle correctly. Both relate
to cache move-in. Another issue is that the present bit in PTEs
is racy.
1) PA-RISC caches have a mind of their own and they can speculatively
load data and instructions for a page as long as there is a entry in
the TLB for the page which allows move-in. TLBs are local to each
CPU. Thus, the TLB entry for a page must be purged before flushing
the page. This is particularly important on SMP systems.
In some of the flush routines, the flush routine would be called
and then the TLB entry would be purged. This was because the flush
routine needed the TLB entry to do the flush.
2) My initial approach to trying the fix the random faults was to
try and use flush_cache_page_if_present for all flush operations.
This actually made things worse and led to a couple of hardware
lockups. It finally dawned on me that some lines weren't being
flushed because the pte check code was racy. This resulted in
random inequivalent mappings to physical pages.
The __flush_cache_page tmpalias flush sets up its own TLB entry
and it doesn't need the existing TLB entry. As long as we can find
the pte pointer for the vm page, we can get the pfn and physical
address of the page. We can also purge the TLB entry for the page
before doing the flush. Further, __flush_cache_page uses a special
TLB entry that inhibits cache move-in.
When switching page mappings, we need to ensure that lines are
removed from the cache. It is not sufficient to just flush the
lines to memory as they may come back.
This made it clear that we needed to implement all the required
flush operations using tmpalias routines. This includes flushes
for user and kernel pages.
After modifying the code to use tmpalias flushes, it became clear
that the random segmentation faults were not fully resolved. The
frequency of faults was worse on systems with a 64 MB L2 (PA8900)
and systems with more CPUs (rp4440).
The warning that I added to flush_cache_page_if_present to detect
pages that couldn't be flushed triggered frequently on some systems.
Helge and I looked at the pages that couldn't be flushed and found
that the PTE was either cleared or for a swap page. Ignoring pages
that were swapped out seemed okay but pages with cleared PTEs seemed
problematic.
I looked at routines related to pte_clear and noticed ptep_clear_flush.
The default implementation just flushes the TLB entry. However, it was
obvious that on parisc we need to flush the cache page as well. If
we don't flush the cache page, stale lines will be left in the cache
and cause random corruption. Once a PTE is cleared, there is no way
to find the physical address associated with the PTE and flush the
associated page at a later time.
I implemented an updated change with a parisc specific version of
ptep_clear_flush. It fixed the random data corruption on Helge's rp4440
and rp3440, as well as on my c8000.
At this point, I realized that I could restore the code where we only
flush in flush_cache_page_if_present if the page has been accessed.
However, for this, we also need to flush the cache when the accessed
bit is cleared in
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