Add an usage for kernel submissions. Waiting for those are mandatory for
dynamic DMA-bufs.
As a precaution this patch also changes all occurrences where fences are
added as part of memory management in TTM, VMWGFX and i915 to use the
new value because it now becomes possible for drivers to ignore fences
with the WRITE usage.
v2: use "must" in documentation, fix whitespaces
v3: separate out some driver changes and better document why some
changes should still be part of this patch.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-5-christian.koenig@amd.com
Instead of distingting between shared and exclusive fences specify
the fence usage while adding fences.
Rework all drivers to use this interface instead and deprecate the old one.
v2: some kerneldoc comments suggested by Daniel
v3: fix a missing case in radeon
v4: rebase on nouveau changes, fix lockdep and temporary disable warning
v5: more documentation updates
v6: separate internal dma_resv changes from this patch, avoids to
disable warning temporary, rebase on upstream changes
v7: fix missed case in lima driver, minimize changes to i915_gem_busy_ioctl
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-3-christian.koenig@amd.com
This change adds the dma_resv_usage enum and allows us to specify why a
dma_resv object is queried for its containing fences.
Additional to that a dma_resv_usage_rw() helper function is added to aid
retrieving the fences for a read or write userspace submission.
This is then deployed to the different query functions of the dma_resv
object and all of their users. When the write paratermer was previously
true we now use DMA_RESV_USAGE_WRITE and DMA_RESV_USAGE_READ otherwise.
v2: add KERNEL/OTHER in separate patch
v3: some kerneldoc suggestions by Daniel
v4: some more kerneldoc suggestions by Daniel, fix missing cases lost in
the rebase pointed out by Bas.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-2-christian.koenig@amd.com
Just use absolute_pointer() like e.g. in commit 545c272232 ("alpha:
Silence -Warray-bounds warnings") to get rid of this warning:
arch/s390/kernel/machine_kexec.c:59:9: warning: ‘memcpy’ offset [0, 511] is out of the bounds [0, 0] [-Warray-bounds]
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
There are more kernel-doc build warnings as below than the ones reported
by kernel test robot recently for this file.
| arch/arm/mach-vexpress/spc.c:125: warning: missing initial short description on line:
| * ve_spc_global_wakeup_irq()
| arch/arm/mach-vexpress/spc.c:131: warning: contents before sections
| arch/arm/mach-vexpress/spc.c:148: warning: missing initial short description on line:
| * ve_spc_cpu_wakeup_irq()
| arch/arm/mach-vexpress/spc.c:154: warning: contents before sections
| arch/arm/mach-vexpress/spc.c:203: warning: missing initial short description on line:
| * ve_spc_powerdown()
| arch/arm/mach-vexpress/spc.c:209: warning: contents before sections
| arch/arm/mach-vexpress/spc.c:231: warning: missing initial short description on line:
| * ve_spc_cpu_in_wfi()
| 7 warnings
Fix all these warnings.
Link: https://lore.kernel.org/r/20220404130207.1162445-2-sudeep.holla@arm.com
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Bernardo reported an error that Nathan bisected down to
(x86_64) defconfig+LTO_CLANG_FULL+X86_PMEM_LEGACY.
LTO vmlinux.o
ld.lld: error: <instantiation>:1:13: redefinition of 'found'
.set found, 0
^
<inline asm>:29:1: while in macro instantiation
extable_type_reg reg=%eax, type=(17 | ((0) << 16))
^
This appears to be another LTO specific issue similar to what was folded
into commit 4b5305decc ("x86/extable: Extend extable functionality"),
where the `.set found, 0` in DEFINE_EXTABLE_TYPE_REG in
arch/x86/include/asm/asm.h conflicts with the symbol for the static
function `found` in arch/x86/kernel/pmem.c.
Assembler .set directive declare symbols with global visibility, so the
assembler may not rename such symbols in the event of a conflict. LTO
could rename static functions if there was a conflict in C sources, but
it cannot see into symbols defined in inline asm.
The symbols are also retained in the symbol table, regardless of LTO.
Give the symbols .L prefixes making them locally visible, so that they
may be renamed for LTO to avoid conflicts, and to drop them from the
symbol table regardless of LTO.
Fixes: 4b5305decc ("x86/extable: Extend extable functionality")
Reported-by: Bernardo Meurer Costa <beme@google.com>
Debugged-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20220329202148.2379697-1-ndesaulniers@google.com
Clang can inline emit_indirect_jump() and then folds constants, which
results in:
| vmlinux.o: warning: objtool: emit_bpf_dispatcher()+0x6a4: relocation to !ENDBR: .text.__x86.indirect_thunk+0x40
| vmlinux.o: warning: objtool: emit_bpf_dispatcher()+0x67d: relocation to !ENDBR: .text.__x86.indirect_thunk+0x40
| vmlinux.o: warning: objtool: emit_bpf_tail_call_indirect()+0x386: relocation to !ENDBR: .text.__x86.indirect_thunk+0x20
| vmlinux.o: warning: objtool: emit_bpf_tail_call_indirect()+0x35d: relocation to !ENDBR: .text.__x86.indirect_thunk+0x20
Suppress the optimization such that it must emit a code reference to
the __x86_indirect_thunk_array[] base.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lkml.kernel.org/r/20220405075531.GB30877@worktop.programming.kicks-ass.net
Don't mark static functions as kernel-doc.
Prevents multiple kernel-doc build warnings:
drivers/gpu/drm/sti/sti_hdmi.c:187: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* HDMI interrupt handler threaded
drivers/gpu/drm/sti/sti_hdmi.c:219: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* HDMI interrupt handler
drivers/gpu/drm/sti/sti_hdmi.c:241: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* Set hdmi active area depending on the drm display mode selected
drivers/gpu/drm/sti/sti_hdmi.c:262: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* Overall hdmi configuration
drivers/gpu/drm/sti/sti_hdmi.c:340: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* Helper to concatenate infoframe in 32 bits word
drivers/gpu/drm/sti/sti_hdmi.c:357: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* Helper to write info frame
drivers/gpu/drm/sti/sti_hdmi.c:427: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* Prepare and configure the AVI infoframe
drivers/gpu/drm/sti/sti_hdmi.c:470: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* Prepare and configure the AUDIO infoframe
drivers/gpu/drm/sti/sti_hdmi.c:555: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst
* Software reset of the hdmi subsystem
Fixes: 5402626c83 ("drm: sti: add HDMI driver")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Aditya Srivastava <yashsri421@gmail.com>
Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Cc: Alain Volmat <alain.volmat@foss.st.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Acked-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Philippe Cornu <philippe.cornu@foss.st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220326235132.25192-1-rdunlap@infradead.org
The two bugs are here:
if (encoder) {
if (bridge && bridge->timings)
The list iterator value 'encoder/bridge' will *always* be set and
non-NULL by drm_for_each_encoder()/list_for_each_entry(), so it is
incorrect to assume that the iterator value will be NULL if the
list is empty or no element is found.
To fix the bug, use a new variable '*_iter' as the list iterator,
while use the old variable 'encoder/bridge' as a dedicated pointer
to point to the found element.
Cc: stable@vger.kernel.org
Fixes: 99e360442f ("drm/stm: Fix bus_flags handling")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
Acked-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
Signed-off-by: Philippe Cornu <philippe.cornu@foss.st.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220327055355.3808-1-xiam0nd.tong@gmail.com
dirty_log_perf_test instantiates a VGICv3 for the guest (if supported by
hardware) to reduce the overhead of guest exits. However, the test does
not actually close the GIC fd when cleaning up the VM between test
iterations, meaning that the VM is never actually destroyed in the
kernel.
While this is generally a bad idea, the bug was detected from the kernel
spewing about duplicate debugfs entries as subsequent VMs happen to
reuse the same FD even though the debugfs directory is still present.
Abstract away the notion of setup/cleanup of the GIC FD from the test
by creating arch-specific helpers for test setup/cleanup. Close the GIC
FD on VM cleanup and do nothing for the other architectures.
Fixes: c340f7899a ("KVM: selftests: Add vgic initialization for dirty log perf test for ARM")
Reviewed-by: Jing Zhang <jingzhangos@google.com>
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220406235615.1447180-3-oupton@google.com
Unfortunately, there is no guarantee that KVM was able to instantiate a
debugfs directory for a particular VM. To that end, KVM shouldn't even
attempt to create new debugfs files in this case. If the specified
parent dentry is NULL, debugfs_create_file() will instantiate files at
the root of debugfs.
For arm64, it is possible to create the vgic-state file outside of a
VM directory, the file is not cleaned up when a VM is destroyed.
Nonetheless, the corresponding struct kvm is freed when the VM is
destroyed.
Nip the problem in the bud for all possible errant debugfs file
creations by initializing kvm->debugfs_dentry to -ENOENT. In so doing,
debugfs_create_file() will fail instead of creating the file in the root
directory.
Cc: stable@kernel.org
Fixes: 929f45e324 ("kvm: no need to check return value of debugfs_create functions")
Signed-off-by: Oliver Upton <oupton@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220406235615.1447180-2-oupton@google.com
When testing a kernel with commit a5905d6af4 ("KVM: arm64:
Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated")
get-reg-list output
vregs: Number blessed registers: 234
vregs: Number registers: 238
vregs: There are 1 new registers.
Consider adding them to the blessed reg list with the following lines:
KVM_REG_ARM_FW_REG(3),
vregs: PASS
...
That output inspired two changes: 1) add the new register to the
blessed list and 2) explain why "Number registers" is actually four
larger than "Number blessed registers" (on the system used for
testing), even though only one register is being stated as new.
The reason is that some registers are host dependent and they get
filtered out when comparing with the blessed list. The system
used for the test apparently had three filtered registers.
Signed-off-by: Andrew Jones <drjones@redhat.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220316125129.392128-1-drjones@redhat.com
When a slip driver is detaching, the slip_close() will act to
cleanup necessary resources and sl->tty is set to NULL in
slip_close(). Meanwhile, the packet we transmit is blocked,
sl_tx_timeout() will be called. Although slip_close() and
sl_tx_timeout() use sl->lock to synchronize, we don`t judge
whether sl->tty equals to NULL in sl_tx_timeout() and the
null pointer dereference bug will happen.
(Thread 1) | (Thread 2)
| slip_close()
| spin_lock_bh(&sl->lock)
| ...
... | sl->tty = NULL //(1)
sl_tx_timeout() | spin_unlock_bh(&sl->lock)
spin_lock(&sl->lock); |
... | ...
tty_chars_in_buffer(sl->tty)|
if (tty->ops->..) //(2) |
... | synchronize_rcu()
We set NULL to sl->tty in position (1) and dereference sl->tty
in position (2).
This patch adds check in sl_tx_timeout(). If sl->tty equals to
NULL, sl_tx_timeout() will goto out.
Signed-off-by: Duoming Zhou <duoming@zju.edu.cn>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20220405132206.55291-1-duoming@zju.edu.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Alexei Starovoitov says:
====================
pull-request: bpf 2022-04-06
We've added 8 non-merge commits during the last 8 day(s) which contain
a total of 9 files changed, 139 insertions(+), 36 deletions(-).
The main changes are:
1) rethook related fixes, from Jiri and Masami.
2) Fix the case when tracing bpf prog is attached to struct_ops, from Martin.
3) Support dual-stack sockets in bpf_tcp_check_syncookie, from Maxim.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf: Adjust bpf_tcp_check_syncookie selftest to test dual-stack sockets
bpf: Support dual-stack sockets in bpf_tcp_check_syncookie
bpf: selftests: Test fentry tracing a struct_ops program
bpf: Resolve to prog->aux->dst_prog->type only for BPF_PROG_TYPE_EXT
rethook: Fix to use WRITE_ONCE() for rethook:: Handler
selftests/bpf: Fix warning comparing pointer to 0
bpf: Fix sparse warnings in kprobe_multi_resolve_syms
bpftool: Explicit errno handling in skeletons
====================
Link: https://lore.kernel.org/r/20220407031245.73026-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Variable dmp is being assigned a value that is never read, the variable is
redundant and can be removed.
Cleans up clang scan build warning:
drivers/message/fusion/mptbase.c:6667:39: warning: Although
the value stored to 'dmp' is used in the enclosing expression,
the value is never actually read from 'dmp' [deadcode.DeadStores]
Link: https://lore.kernel.org/r/20220318003927.81471-1-colin.i.king@gmail.com
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The start_addres argument of mpt3sas_check_same_4gb_region() was misnamed
in the function kdoc comment, resulting in the following warning when
compiling with W=1.
drivers/scsi/mpt3sas/mpt3sas_base.c:5728: warning: Function parameter or
member 'start_address' not described in 'mpt3sas_check_same_4gb_region'
drivers/scsi/mpt3sas/mpt3sas_base.c:5728: warning: Excess function
parameter 'reply_pool_start_address' description in
'mpt3sas_check_same_4gb_region'
Fix the argument name in the function kdoc comment to avoid it. While at
it, remove a useless blank line between the kdoc and function code.
Link: https://lore.kernel.org/r/20220404050041.594774-1-damien.lemoal@opensource.wdc.com
Acked-by: Sreekanth Reddy <sreekanth.reddy@broadcom.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
In 1448769c9c ("random: check for signal_pending() outside of
need_resched() check"), Jann pointed out that we previously were only
checking the TIF_NOTIFY_SIGNAL and TIF_SIGPENDING flags if the process
had TIF_NEED_RESCHED set, which meant in practice, super long reads to
/dev/[u]random would delay signal handling by a long time. I tried this
using the below program, and indeed I wasn't able to interrupt a
/dev/urandom read until after several megabytes had been read. The bug
he fixed has always been there, and so code that reads from /dev/urandom
without checking the return value of read() has mostly worked for a long
time, for most sizes, not just for <= 256.
Maybe it makes sense to keep that code working. The reason it was so
small prior, ignoring the fact that it didn't work anyway, was likely
because /dev/random used to block, and that could happen for pretty
large lengths of time while entropy was gathered. But now, it's just a
chacha20 call, which is extremely fast and is just operating on pure
data, without having to wait for some external event. In that sense,
/dev/[u]random is a lot more like /dev/zero.
Taking a page out of /dev/zero's read_zero() function, it always returns
at least one chunk, and then checks for signals after each chunk. Chunk
sizes there are of length PAGE_SIZE. Let's just copy the same thing for
/dev/[u]random, and check for signals and cond_resched() for every
PAGE_SIZE amount of data. This makes the behavior more consistent with
expectations, and should mitigate the impact of Jann's fix for the
age-old signal check bug.
---- test program ----
#include <unistd.h>
#include <signal.h>
#include <stdio.h>
#include <sys/random.h>
static unsigned char x[~0U];
static void handle(int) { }
int main(int argc, char *argv[])
{
pid_t pid = getpid(), child;
signal(SIGUSR1, handle);
if (!(child = fork())) {
for (;;)
kill(pid, SIGUSR1);
}
pause();
printf("interrupted after reading %zd bytes\n", getrandom(x, sizeof(x), 0));
kill(child, SIGTERM);
return 0;
}
Cc: Jann Horn <jannh@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This reverts commit 602946ec2f.
If CONFIG_HIGHMEM is enabled, no highmem will be added with max_mapnr
set to max_low_pfn, see mem_init():
for (pfn = highmem_mapnr; pfn < max_mapnr; ++pfn) {
...
free_highmem_page();
}
Now that virt_addr_valid() has been fixed in the previous commit, we can
revert the change to max_mapnr.
Fixes: 602946ec2f ("powerpc: Set max_mapnr correctly")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reported-by: Erhard F. <erhard_f@mailbox.org>
[mpe: Update change log to reflect series reordering]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220406145802.538416-2-mpe@ellerman.id.au
mpe: On 64-bit Book3E vmalloc space starts at 0x8000000000000000.
Because of the way __pa() works we have:
__pa(0x8000000000000000) == 0, and therefore
virt_to_pfn(0x8000000000000000) == 0, and therefore
virt_addr_valid(0x8000000000000000) == true
Which is wrong, virt_addr_valid() should be false for vmalloc space.
In fact all vmalloc addresses that alias with a valid PFN will return
true from virt_addr_valid(). That can cause bugs with hardened usercopy
as described below by Kefeng Wang:
When running ethtool eth0 on 64-bit Book3E, a BUG occurred:
usercopy: Kernel memory exposure attempt detected from SLUB object not in SLUB page?! (offset 0, size 1048)!
kernel BUG at mm/usercopy.c:99
...
usercopy_abort+0x64/0xa0 (unreliable)
__check_heap_object+0x168/0x190
__check_object_size+0x1a0/0x200
dev_ethtool+0x2494/0x2b20
dev_ioctl+0x5d0/0x770
sock_do_ioctl+0xf0/0x1d0
sock_ioctl+0x3ec/0x5a0
__se_sys_ioctl+0xf0/0x160
system_call_exception+0xfc/0x1f0
system_call_common+0xf8/0x200
The code shows below,
data = vzalloc(array_size(gstrings.len, ETH_GSTRING_LEN));
copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN))
The data is alloced by vmalloc(), virt_addr_valid(ptr) will return true
on 64-bit Book3E, which leads to the panic.
As commit 4dd7554a64 ("powerpc/64: Add VIRTUAL_BUG_ON checks for __va
and __pa addresses") does, make sure the virt addr above PAGE_OFFSET in
the virt_addr_valid() for 64-bit, also add upper limit check to make
sure the virt is below high_memory.
Meanwhile, for 32-bit PAGE_OFFSET is the virtual address of the start
of lowmem, high_memory is the upper low virtual address, the check is
suitable for 32-bit, this will fix the issue mentioned in commit
602946ec2f ("powerpc: Set max_mapnr correctly") too.
On 32-bit there is a similar problem with high memory, that was fixed in
commit 602946ec2f ("powerpc: Set max_mapnr correctly"), but that
commit breaks highmem and needs to be reverted.
We can't easily fix __pa(), we have code that relies on its current
behaviour. So for now add extra checks to virt_addr_valid().
For 64-bit Book3S the extra checks are not necessary, the combination of
virt_to_pfn() and pfn_valid() should yield the correct result, but they
are harmless.
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
[mpe: Add additional change log detail]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220406145802.538416-1-mpe@ellerman.id.au
Since gen6 we use FPGA_DBG register to detect unclaimed MMIO registers.
This register is in the display engine IP and can only ever detect
unclaimed accesses to registers in this area. However sometimes there
are reports of this triggering for registers in other areas, which
should not be possible.
Right now we always warn after the read/write of registers going through
unclaimed_reg_debug(). However places using __raw_uncore_* may be
triggering the unclaimed access and those being later accounted to a
different register. Let's warn both before and after the read/write
with a slightly different message, so it's clear if the register
reported in the warning is actually the culprit.
Commit dda960335e ("drm/i915: Just clear the mmiodebug before a
register access") attempted to solve the same issue by removing the
warning when if FPGA_DBG flags before the mmio read/write. However, it
doesn't solve it completely as FPGA_DBG may remain set when reading
registers outside display. So in the end the check after the mmio
read/write triggers the warning pointing to the wrong register.
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220405001149.2675226-1-lucas.demarchi@intel.com
OF framebuffers do not have an underlying device in the Linux
device hierarchy. Do a regular unregister call instead of hot
unplugging such a non-existing device. Fixes a NULL dereference.
An example error message on ppc64le is shown below.
BUG: Kernel NULL pointer dereference on read at 0x00000060
Faulting instruction address: 0xc00000000080dfa4
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
[...]
CPU: 2 PID: 139 Comm: systemd-udevd Not tainted 5.17.0-ae085d7f9365 #1
NIP: c00000000080dfa4 LR: c00000000080df9c CTR: c000000000797430
REGS: c000000004132fe0 TRAP: 0300 Not tainted (5.17.0-ae085d7f9365)
MSR: 8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE> CR: 28228282 XER: 20000000
CFAR: c00000000000c80c DAR: 0000000000000060 DSISR: 40000000 IRQMASK: 0
GPR00: c00000000080df9c c000000004133280 c00000000169d200 0000000000000029
GPR04: 00000000ffffefff c000000004132f90 c000000004132f88 0000000000000000
GPR08: c0000000015658f8 c0000000015cd200 c0000000014f57d0 0000000048228283
GPR12: 0000000000000000 c00000003fffe300 0000000020000000 0000000000000000
GPR16: 0000000000000000 0000000113fc4a40 0000000000000005 0000000113fcfb80
GPR20: 000001000f7283b0 0000000000000000 c000000000e4a588 c000000000e4a5b0
GPR24: 0000000000000001 00000000000a0000 c008000000db0168 c0000000021f6ec0
GPR28: c0000000016d65a8 c000000004b36460 0000000000000000 c0000000016d64b0
NIP [c00000000080dfa4] do_remove_conflicting_framebuffers+0x184/0x1d0
[c000000004133280] [c00000000080df9c] do_remove_conflicting_framebuffers+0x17c/0x1d0 (unreliable)
[c000000004133350] [c00000000080e4d0] remove_conflicting_framebuffers+0x60/0x150
[c0000000041333a0] [c00000000080e6f4] remove_conflicting_pci_framebuffers+0x134/0x1b0
[c000000004133450] [c008000000e70438] drm_aperture_remove_conflicting_pci_framebuffers+0x90/0x100 [drm]
[c000000004133490] [c008000000da0ce4] bochs_pci_probe+0x6c/0xa64 [bochs]
[...]
[c000000004133db0] [c00000000002aaa0] system_call_exception+0x170/0x2d0
[c000000004133e10] [c00000000000c3cc] system_call_common+0xec/0x250
The bug [1] was introduced by commit 27599aacba ("fbdev: Hot-unplug
firmware fb devices on forced removal"). Most firmware framebuffers
have an underlying platform device, which can be hot-unplugged
before loading the native graphics driver. OF framebuffers do not
(yet) have that device. Fix the code by unregistering the framebuffer
as before without a hot unplug.
Tested with 5.17 on qemu ppc64le emulation.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 27599aacba ("fbdev: Hot-unplug firmware fb devices on forced removal")
Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Cc: Zack Rusin <zackr@vmware.com>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: stable@vger.kernel.org # v5.11+
Cc: Helge Deller <deller@gmx.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Zheyu Ma <zheyuma97@gmail.com>
Cc: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Link: https://lore.kernel.org/all/YkHXO6LGHAN0p1pq@debian/ # [1]
Link: https://patchwork.freedesktop.org/patch/msgid/20220404194402.29974-1-tzimmermann@suse.de
