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[PATCH] nommu: pass NULL argument to vma_iter_prealloc()

by Hajime Tazaki

When deleting a vma entry from a maple tree, it has to pass NULL to vma_iter_prealloc() in order to calculate internal state of the tree, but it passed a wrong argument. As a result, nommu kernels crashed upon accessing a vma iterator, such as acct_collect() reading the size of vma entries after do_munmap(). This commit fixes this issue by passing a right argument to the preallocation call. Fixes: b5df09226450 ("mm: set up vma iterator for vma_iter_prealloc() calls") Cc: stable(a)vger.kernel.org Reviewed-by: Liam R. Howlett <Liam.Howlett(a)Oracle.com> Signed-off-by: Hajime Tazaki <thehajime(a)gmail.com> --- mm/nommu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/nommu.c b/mm/nommu.c index 385b0c15add8..0c708f85408d 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -573,7 +573,7 @@ static int delete_vma_from_mm(struct vm_area_struct *vma) VMA_ITERATOR(vmi, vma->vm_mm, vma->vm_start); vma_iter_config(&vmi, vma->vm_start, vma->vm_end); - if (vma_iter_prealloc(&vmi, vma)) { + if (vma_iter_prealloc(&vmi, NULL)) { pr_warn("Allocation of vma tree for process %d failed\n", current->pid); return -ENOMEM; -- 2.43.0

3 months, 1 week

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[PATCH] amba: Fix atomicity violation in amba_match()

by Qiu-ji Chen

Atomicity violation occurs during consecutive reads of pcdev->driver_override. Consider a scenario: after pvdev->driver_override passes the if statement, due to possible concurrency, pvdev->driver_override may change. This leads to pvdev->driver_override passing the condition with an old value, but entering the return !strcmp(pcdev->driver_override, drv->name); statement with a new value. This causes the function to return an unexpected result. Since pvdev->driver_override is a string that is modified byte by byte, without considering atomicity, data races may cause a partially modified pvdev->driver_override to enter both the condition and return statements, resulting in an error. To fix this, we suggest protecting all reads of pvdev->driver_override with a lock, and storing the result of the strcmp() function in a new variable retval. This ensures that pvdev->driver_override does not change during the entire operation, allowing the function to return the expected result. This possible bug is found by an experimental static analysis tool developed by our team. This tool analyzes the locking APIs to extract function pairs that can be concurrently executed, and then analyzes the instructions in the paired functions to identify possible concurrency bugs including data races and atomicity violations. Fixes: 5150a8f07f6c ("amba: reorder functions") Cc: stable(a)vger.kernel.org Signed-off-by: Qiu-ji Chen <chenqiuji666(a)gmail.com> --- drivers/amba/bus.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c index 34bc880ca20b..e310f4f83b27 100644 --- a/drivers/amba/bus.c +++ b/drivers/amba/bus.c @@ -209,6 +209,7 @@ static int amba_match(struct device *dev, const struct device_driver *drv) { struct amba_device *pcdev = to_amba_device(dev); const struct amba_driver *pcdrv = to_amba_driver(drv); + int retval; mutex_lock(&pcdev->periphid_lock); if (!pcdev->periphid) { @@ -230,8 +231,14 @@ static int amba_match(struct device *dev, const struct device_driver *drv) mutex_unlock(&pcdev->periphid_lock); /* When driver_override is set, only bind to the matching driver */ - if (pcdev->driver_override) - return !strcmp(pcdev->driver_override, drv->name); + + device_lock(dev); + if (pcdev->driver_override) { + retval = !strcmp(pcdev->driver_override, drv->name); + device_unlock(dev); + return retval; + } + device_unlock(dev); return amba_lookup(pcdrv->id_table, pcdev) != NULL; } -- 2.34.1

3 months, 1 week

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[PATCH] cdx: Fix atomicity violation in cdx_bus_match() and cdx_probe()

by Qiu-ji Chen

An atomicity violation occurs during consecutive reads of the variable cdx_dev->driver_override. Imagine a scenario: while evaluating the statement if (cdx_dev->driver_override && strcmp(cdx_dev->driver_override, drv->name)), the value of cdx_dev->driver_override changes, leading to an inconsistency where the value of cdx_dev->driver_override is the old value when passing the non-null check, but the new value when evaluated by strcmp(). This causes an inconsistency. The second error occurs during the validation of cdx_dev->driver_override. The logic of this error is similar to the first one, as the entire process is not protected by a lock, leading to an inconsistency in the values of cdx_dev->driver_override before and after the reads. The third error occurs in driver_override_show() when executing the statement return sysfs_emit(buf, "%s\n", cdx_dev->driver_override);. Since the string changes byte by byte, it is possible for a partially modified cdx_dev->driver_override value to be used in this statement, leading to an incorrect return value from the program. To fix these issues, for the first and second problems, since we need to protect the entire process of reading the variable cdx_dev->driver_override with a lock, we introduced a variable ret and an out block. For each branch in this section, we replaced the return statements with assignments to the variable ret, and then used a goto statement to directly execute the out block, making the code overall more concise. For the third problem, we adopted a similar approach to the one used in the modalias_show() function, protecting the process of reading cdx_dev->driver_override with a lock, ensuring that the program runs correctly. This possible bug is found by an experimental static analysis tool developed by our team. This tool analyzes the locking APIs to extract function pairs that can be concurrently executed, and then analyzes the instructions in the paired functions to identify possible concurrency bugs including data races and atomicity violations. Fixes: 2959ab247061 ("cdx: add the cdx bus driver") Fixes: 48a6c7bced2a ("cdx: add device attributes") Cc: stable(a)vger.kernel.org Signed-off-by: Qiu-ji Chen <chenqiuji666(a)gmail.com> --- drivers/cdx/cdx.c | 37 +++++++++++++++++++++++++++---------- 1 file changed, 27 insertions(+), 10 deletions(-) diff --git a/drivers/cdx/cdx.c b/drivers/cdx/cdx.c index 07371cb653d3..fae03c89f818 100644 --- a/drivers/cdx/cdx.c +++ b/drivers/cdx/cdx.c @@ -268,6 +268,7 @@ static int cdx_bus_match(struct device *dev, const struct device_driver *drv) const struct cdx_driver *cdx_drv = to_cdx_driver(drv); const struct cdx_device_id *found_id = NULL; const struct cdx_device_id *ids; + int ret = false; if (cdx_dev->is_bus) return false; @@ -275,28 +276,40 @@ static int cdx_bus_match(struct device *dev, const struct device_driver *drv) ids = cdx_drv->match_id_table; /* When driver_override is set, only bind to the matching driver */ - if (cdx_dev->driver_override && strcmp(cdx_dev->driver_override, drv->name)) - return false; + device_lock(dev); + if (cdx_dev->driver_override && strcmp(cdx_dev->driver_override, drv->name)) { + ret = false; + goto out; + } found_id = cdx_match_id(ids, cdx_dev); - if (!found_id) - return false; + if (!found_id) { + ret = false; + goto out; + } do { /* * In case override_only was set, enforce driver_override * matching. */ - if (!found_id->override_only) - return true; - if (cdx_dev->driver_override) - return true; + if (!found_id->override_only) { + ret = true; + goto out; + } + if (cdx_dev->driver_override) { + ret = true; + goto out; + } ids = found_id + 1; found_id = cdx_match_id(ids, cdx_dev); } while (found_id); - return false; + ret = false; +out: + device_unlock(dev); + return ret; } static int cdx_probe(struct device *dev) @@ -470,8 +483,12 @@ static ssize_t driver_override_show(struct device *dev, struct device_attribute *attr, char *buf) { struct cdx_device *cdx_dev = to_cdx_device(dev); + ssize_t len; - return sysfs_emit(buf, "%s\n", cdx_dev->driver_override); + device_lock(dev); + len = sysfs_emit(buf, "%s\n", cdx_dev->driver_override); + device_unlock(dev); + return len; } static DEVICE_ATTR_RW(driver_override); -- 2.34.1

3 months, 1 week

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[PATCH] bus/fls-mc: Fix possible UAF error in driver_override_show()

by Qiu-ji Chen

There is a data race between the functions driver_override_show() and driver_override_store(). In the driver_override_store() function, the assignment to ret calls driver_set_override(), which frees the old value while writing the new value to dev. If a race occurs, it may cause a use-after-free (UAF) error in driver_override_show(). To fix this issue, we adopted a logic similar to the driver_override_show() function in vmbus_drv.c, where the dev is protected by a lock to prevent its value from changing. This possible bug is found by an experimental static analysis tool developed by our team. This tool analyzes the locking APIs to extract function pairs that can be concurrently executed, and then analyzes the instructions in the paired functions to identify possible concurrency bugs including data races and atomicity violations. Fixes: 1f86a00c1159 ("bus/fsl-mc: add support for 'driver_override' in the mc-bus") Cc: stable(a)vger.kernel.org Signed-off-by: Qiu-ji Chen <chenqiuji666(a)gmail.com> --- drivers/bus/fsl-mc/fsl-mc-bus.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c index 930d8a3ba722..62a9da88b4c9 100644 --- a/drivers/bus/fsl-mc/fsl-mc-bus.c +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c @@ -201,8 +201,12 @@ static ssize_t driver_override_show(struct device *dev, struct device_attribute *attr, char *buf) { struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev); + ssize_t len; - return snprintf(buf, PAGE_SIZE, "%s\n", mc_dev->driver_override); + device_lock(dev); + len = snprintf(buf, PAGE_SIZE, "%s\n", mc_dev->driver_override); + device_unlock(dev); + return len; } static DEVICE_ATTR_RW(driver_override); -- 2.34.1

3 months, 1 week

1
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Re: [PATCH 1/1] x86/cpu: Add INTEL_LUNARLAKE_M to X86_BUG_MONITOR

by Rafael J. Wysocki

On Tue, Nov 12, 2024 at 3:02 PM Len Brown <lenb(a)kernel.org> wrote: > > On Tue, Nov 12, 2024 at 8:14 AM Rafael J. Wysocki <rafael(a)kernel.org> wrote: > > > > On Tue, Nov 12, 2024 at 2:12 PM Len Brown <lenb(a)kernel.org> wrote: > > > > > > On Tue, Nov 12, 2024 at 6:44 AM Rafael J. Wysocki <rafael(a)kernel.org> wrote: > > > > > > > > - if (boot_cpu_has(X86_FEATURE_MWAIT) && c->x86_vfm == INTEL_ATOM_GOLDMONT) > > > > > + if (boot_cpu_has(X86_FEATURE_MWAIT) && > > > > > + (c->x86_vfm == INTEL_ATOM_GOLDMONT > > > > > + || c->x86_vfm == INTEL_LUNARLAKE_M)) > > > > > > > > I would put the || at the end of the previous line, that is > > > > > > > > > It isn't my personal preference for human readability either, > > > but this is what scripts/Lindent does... > > > > Well, it doesn't match the coding style of the first line ... > > Fair observation. > > I'll bite. > > If you took the existing intel.c and added it as a patch to the kernel, > the resulting checkpatch would have 6 errors and 33 warnings. > > If you ran Lindent on the existing intel.c, the resulting diff would be > 408 lines -- 1 file changed, 232 insertions(+), 176 deletions(-) > > This for a file that is only 1300 lines long. > > If whitespace nirvana is the goal, tools are the answer, not the valuable > cycles of human reviewers. Well, the advice always given is to follow the coding style of the given fine in the first place. checkpatch reflects the preferences of its author is this particular respect and maintainers' preferences tend to differ from one to another.

3 months, 1 week

1
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[PATCH] kbuild: switch from lz4c to lz4 for compression

by Parth Pancholi

From: Parth Pancholi <parth.pancholi(a)toradex.com> Replace lz4c with lz4 for kernel image compression. Although lz4 and lz4c are functionally similar, lz4c has been deprecated upstream since 2018. Since as early as Ubuntu 16.04 and Fedora 25, lz4 and lz4c have been packaged together, making it safe to update the requirement from lz4c to lz4. Consequently, some distributions and build systems, such as OpenEmbedded, have fully transitioned to using lz4. OpenEmbedded core adopted this change in commit fe167e082cbd ("bitbake.conf: require lz4 instead of lz4c"), causing compatibility issues when building the mainline kernel in the latest OpenEmbedded environment, as seen in the errors below. This change maintains compatibility with current kernel builds because both tools have a similar command-line interface while fixing the mainline kernel build failures with the latest master OpenEmbedded builds associated with the mentioned compatibility issues. LZ4 arch/arm/boot/compressed/piggy_data /bin/sh: 1: lz4c: not found ... ... ERROR: oe_runmake failed Cc: stable(a)vger.kernel.org Link: https://github.com/lz4/lz4/pull/553 Suggested-by: Francesco Dolcini <francesco.dolcini(a)toradex.com> Signed-off-by: Parth Pancholi <parth.pancholi(a)toradex.com> --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Makefile b/Makefile index 79192a3024bf..7630f763f5b2 100644 --- a/Makefile +++ b/Makefile @@ -508,7 +508,7 @@ KGZIP = gzip KBZIP2 = bzip2 KLZOP = lzop LZMA = lzma -LZ4 = lz4c +LZ4 = lz4 XZ = xz ZSTD = zstd -- 2.34.1

3 months, 1 week

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Re: [PATCH 1/1] x86/cpu: Add INTEL_LUNARLAKE_M to X86_BUG_MONITOR

by Rafael J. Wysocki

On Tue, Nov 12, 2024 at 2:12 PM Len Brown <lenb(a)kernel.org> wrote: > > On Tue, Nov 12, 2024 at 6:44 AM Rafael J. Wysocki <rafael(a)kernel.org> wrote: > > > > - if (boot_cpu_has(X86_FEATURE_MWAIT) && c->x86_vfm == INTEL_ATOM_GOLDMONT) > > > + if (boot_cpu_has(X86_FEATURE_MWAIT) && > > > + (c->x86_vfm == INTEL_ATOM_GOLDMONT > > > + || c->x86_vfm == INTEL_LUNARLAKE_M)) > > > > I would put the || at the end of the previous line, that is > > > It isn't my personal preference for human readability either, > but this is what scripts/Lindent does... Well, it doesn't match the coding style of the first line ...

3 months, 1 week

1
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Re: [PATCH 6.11 000/184] 6.11.8-rc1 review

by Ronald Warsow

Hi Greg no regressions here on x86_64 (RKL, Intel 11th Gen. CPU) Thanks Tested-by: Ronald Warsow <rwarsow(a)gmx.de>

3 months, 1 week

1
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[PATCH 0/4] Venus driver fixes to avoid possible OOB accesses

by Vikash Garodia

This series primarily adds check at relevant places in venus driver where there are possible OOB accesses due to unexpected payload from venus firmware. The patches describes the specific OOB possibility. Please review and share your feedback. Signed-off-by: Vikash Garodia <quic_vgarodia(a)quicinc.com> --- Vikash Garodia (4): media: venus: hfi_parser: add check to avoid out of bound access media: venus: hfi_parser: avoid OOB access beyond payload word count media: venus: hfi: add check to handle incorrect queue size media: venus: hfi: add a check to handle OOB in sfr region drivers/media/platform/qcom/venus/hfi_parser.c | 6 +++++- drivers/media/platform/qcom/venus/hfi_venus.c | 15 +++++++++++++-- 2 files changed, 18 insertions(+), 3 deletions(-) --- base-commit: c7ccf3683ac9746b263b0502255f5ce47f64fe0a change-id: 20241104-venus_oob-0343b143d61d Best regards, -- Vikash Garodia <quic_vgarodia(a)quicinc.com>

3 months, 1 week

3
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[PATCH v2 0/1] ufs: ufs_sb_private_info: remove unused s_{2,3}apb fields

by Agathe Porte

v2: add Cc stable because the UBSAN might be triggered of previous stable kernels as well. Agathe Porte (1): ufs: ufs_sb_private_info: remove unused s_{2,3}apb fields fs/ufs/super.c | 4 ---- fs/ufs/ufs_fs.h | 4 ---- 2 files changed, 8 deletions(-) -- 2.43.0

3 months, 1 week

2
3
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