In the Linux kernel, the following vulnerability has been resolved:
qed: allow sleep in qed_mcp_trace_dump()
By default, qed_mcp_cmd_and_union() delays 10us at a time in a loop
that can run 500K times, so calls to qed_mcp_nvm_rd_cmd()
may block the current thread for over 5s.
We observed thread scheduling delays over 700ms in production,
with stacktraces pointing to this code as the culprit.
qed_mcp_trace_dump() is called from ethtool, so sleeping is permitted.
It already can sleep in qed_mcp_halt(), which calls qed_mcp_cmd().
Add a "can sleep" parameter to qed_find_nvram_image() and
qed_nvram_read() so they can sleep during qed_mcp_trace_dump().
qed_mcp_trace_get_meta_info() and qed_mcp_trace_read_meta(),
called only by qed_mcp_trace_dump(), allow these functions to sleep.
I can't tell if the other caller (qed_grc_dump_mcp_hw_dump()) can sleep,
so keep b_can_sleep set to false when it calls these functions.
An example stacktrace from a custom warning we added to the kernel
showing a thread that has not scheduled despite long needing resched:
[ 2745.362925,17] ------------[ cut here ]------------
[ 2745.362941,17] WARNING: CPU: 23 PID: 5640 at arch/x86/kernel/irq.c:233 do_IRQ+0x15e/0x1a0()
[ 2745.362946,17] Thread not rescheduled for 744 ms after irq 99
[ 2745.362956,17] Modules linked in: ...
[ 2745.363339,17] CPU: 23 PID: 5640 Comm: lldpd Tainted: P O 4.4.182+ #202104120910+6d1da174272d.61x
[ 2745.363343,17] Hardware name: FOXCONN MercuryB/Quicksilver Controller, BIOS H11P1N09 07/08/2020
[ 2745.363346,17] 0000000000000000 ffff885ec07c3ed8 ffffffff8131eb2f ffff885ec07c3f20
[ 2745.363358,17] ffffffff81d14f64 ffff885ec07c3f10 ffffffff81072ac2 ffff88be98ed0000
[ 2745.363369,17] 0000000000000063 0000000000000174 0000000000000074 0000000000000000
[ 2745.363379,17] Call Trace:
[ 2745.363382,17] <IRQ> [<ffffffff8131eb2f>] dump_stack+0x8e/0xcf
[ 2745.363393,17] [<ffffffff81072ac2>] warn_slowpath_common+0x82/0xc0
[ 2745.363398,17] [<ffffffff81072b4c>] warn_slowpath_fmt+0x4c/0x50
[ 2745.363404,17] [<ffffffff810d5a8e>] ? rcu_irq_exit+0xae/0xc0
[ 2745.363408,17] [<ffffffff817c99fe>] do_IRQ+0x15e/0x1a0
[ 2745.363413,17] [<ffffffff817c7ac9>] common_interrupt+0x89/0x89
[ 2745.363416,17] <EOI> [<ffffffff8132aa74>] ? delay_tsc+0x24/0x50
[ 2745.363425,17] [<ffffffff8132aa04>] __udelay+0x34/0x40
[ 2745.363457,17] [<ffffffffa04d45ff>] qed_mcp_cmd_and_union+0x36f/0x7d0 [qed]
[ 2745.363473,17] [<ffffffffa04d5ced>] qed_mcp_nvm_rd_cmd+0x4d/0x90 [qed]
[ 2745.363490,17] [<ffffffffa04e1dc7>] qed_mcp_trace_dump+0x4a7/0x630 [qed]
[ 2745.363504,17] [<ffffffffa04e2556>] ? qed_fw_asserts_dump+0x1d6/0x1f0 [qed]
[ 2745.363520,17] [<ffffffffa04e4ea7>] qed_dbg_mcp_trace_get_dump_buf_size+0x37/0x80 [qed]
[ 2745.363536,17] [<ffffffffa04ea881>] qed_dbg_feature_size+0x61/0xa0 [qed]
[ 2745.363551,17] [<ffffffffa04eb427>] qed_dbg_all_data_size+0x247/0x260 [qed]
[ 2745.363560,17] [<ffffffffa0482c10>] qede_get_regs_len+0x30/0x40 [qede]
[ 2745.363566,17] [<ffffffff816c9783>] ethtool_get_drvinfo+0xe3/0x190
[ 2745.363570,17] [<ffffffff816cc152>] dev_ethtool+0x1362/0x2140
[ 2745.363575,17] [<ffffffff8109bcc6>] ? finish_task_switch+0x76/0x260
[ 2745.363580,17] [<ffffffff817c2116>] ? __schedule+0x3c6/0x9d0
[ 2745.363585,17] [<ffffffff810dbd50>] ? hrtimer_start_range_ns+0x1d0/0x370
[ 2745.363589,17] [<ffffffff816c1e5b>] ? dev_get_by_name_rcu+0x6b/0x90
[ 2745.363594,17] [<ffffffff816de6a8>] dev_ioctl+0xe8/0x710
[ 2745.363599,17] [<ffffffff816a58a8>] sock_do_ioctl+0x48/0x60
[ 2745.363603,17] [<ffffffff816a5d87>] sock_ioctl+0x1c7/0x280
[ 2745.363608,17] [<ffffffff8111f393>] ? seccomp_phase1+0x83/0x220
[ 2745.363612,17] [<ffffffff811e3503>] do_vfs_ioctl+0x2b3/0x4e0
[ 2745.363616,17] [<ffffffff811e3771>] SyS_ioctl+0x41/0x70
[ 2745.363619,17] [<ffffffff817c6ffe>] entry_SYSCALL_64_fastpath+0x1e/0x79
[ 2745.363622,17] ---[ end trace f6954aa440266421 ]---
In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: core: Fix handling of lrbp->cmd
ufshcd_queuecommand() may be called two times in a row for a SCSI command
before it is completed. Hence make the following changes:
- In the functions that submit a command, do not check the old value of
lrbp->cmd nor clear lrbp->cmd in error paths.
- In ufshcd_release_scsi_cmd(), do not clear lrbp->cmd.
See also scsi_send_eh_cmnd().
This commit prevents that the following appears if a command times out:
WARNING: at drivers/ufs/core/ufshcd.c:2965 ufshcd_queuecommand+0x6f8/0x9a8
Call trace:
ufshcd_queuecommand+0x6f8/0x9a8
scsi_send_eh_cmnd+0x2c0/0x960
scsi_eh_test_devices+0x100/0x314
scsi_eh_ready_devs+0xd90/0x114c
scsi_error_handler+0x2b4/0xb70
kthread+0x16c/0x1e0
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix potential null dereference
The adev->dm.dc pointer can be NULL and dereferenced in amdgpu_dm_fini()
without checking.
Add a NULL pointer check before calling dc_dmub_srv_destroy().
Found by Linux Verification Center (linuxtesting.org) with SVACE.
In the Linux kernel, the following vulnerability has been resolved:
virtio_net: Fix error unwinding of XDP initialization
When initializing XDP in virtnet_open(), some rq xdp initialization
may hit an error causing net device open failed. However, previous
rqs have already initialized XDP and enabled NAPI, which is not the
expected behavior. Need to roll back the previous rq initialization
to avoid leaks in error unwinding of init code.
Also extract helper functions of disable and enable queue pairs.
Use newly introduced disable helper function in error unwinding and
virtnet_close. Use enable helper function in virtnet_open.
In the Linux kernel, the following vulnerability has been resolved:
start_kernel: Add __no_stack_protector function attribute
Back during the discussion of
commit a9a3ed1eff36 ("x86: Fix early boot crash on gcc-10, third try")
we discussed the need for a function attribute to control the omission
of stack protectors on a per-function basis; at the time Clang had
support for no_stack_protector but GCC did not. This was fixed in
gcc-11. Now that the function attribute is available, let's start using
it.
Callers of boot_init_stack_canary need to use this function attribute
unless they're compiled with -fno-stack-protector, otherwise the canary
stored in the stack slot of the caller will differ upon the call to
boot_init_stack_canary. This will lead to a call to __stack_chk_fail()
then panic.
In the Linux kernel, the following vulnerability has been resolved:
kobject: Add sanity check for kset->kobj.ktype in kset_register()
When I register a kset in the following way:
static struct kset my_kset;
kobject_set_name(&my_kset.kobj, "my_kset");
ret = kset_register(&my_kset);
A null pointer dereference exception is occurred:
[ 4453.568337] Unable to handle kernel NULL pointer dereference at \
virtual address 0000000000000028
... ...
[ 4453.810361] Call trace:
[ 4453.813062] kobject_get_ownership+0xc/0x34
[ 4453.817493] kobject_add_internal+0x98/0x274
[ 4453.822005] kset_register+0x5c/0xb4
[ 4453.825820] my_kobj_init+0x44/0x1000 [my_kset]
... ...
Because I didn't initialize my_kset.kobj.ktype.
According to the description in Documentation/core-api/kobject.rst:
- A ktype is the type of object that embeds a kobject. Every structure
that embeds a kobject needs a corresponding ktype.
So add sanity check to make sure kset->kobj.ktype is not NULL.
In the Linux kernel, the following vulnerability has been resolved:
iommu: Fix error unwind in iommu_group_alloc()
If either iommu_group_grate_file() fails then the
iommu_group is leaked.
Destroy it on these error paths.
Found by kselftest/iommu/iommufd_fail_nth
In the Linux kernel, the following vulnerability has been resolved:
ionic: catch failure from devlink_alloc
Add a check for NULL on the alloc return. If devlink_alloc() fails and
we try to use devlink_priv() on the NULL return, the kernel gets very
unhappy and panics. With this fix, the driver load will still fail,
but at least it won't panic the kernel.
In the Linux kernel, the following vulnerability has been resolved:
ext4: improve error handling from ext4_dirhash()
The ext4_dirhash() will *almost* never fail, especially when the hash
tree feature was first introduced. However, with the addition of
support of encrypted, casefolded file names, that function can most
certainly fail today.
So make sure the callers of ext4_dirhash() properly check for
failures, and reflect the errors back up to their callers.
In the Linux kernel, the following vulnerability has been resolved:
iw_cxgb4: Fix potential NULL dereference in c4iw_fill_res_cm_id_entry()
This condition needs to match the previous "if (epcp->state == LISTEN) {"
exactly to avoid a NULL dereference of either "listen_ep" or "ep". The
problem is that "epcp" has been re-assigned so just testing
"if (epcp->state == LISTEN) {" a second time is not sufficient.