November 2024 - Linux-stable-mirror

FAILED: patch "[PATCH] mm: resolve faulty mmap_region() error path behaviour" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 5de195060b2e251a835f622759550e6202167641 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111150-kinsman-t-shirt-f064@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 5de195060b2e251a835f622759550e6202167641 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Date: Tue, 29 Oct 2024 18:11:48 +0000 Subject: [PATCH] mm: resolve faulty mmap_region() error path behaviour The mmap_region() function is somewhat terrifying, with spaghetti-like control flow and numerous means by which issues can arise and incomplete state, memory leaks and other unpleasantness can occur. A large amount of the complexity arises from trying to handle errors late in the process of mapping a VMA, which forms the basis of recently observed issues with resource leaks and observable inconsistent state. Taking advantage of previous patches in this series we move a number of checks earlier in the code, simplifying things by moving the core of the logic into a static internal function __mmap_region(). Doing this allows us to perform a number of checks up front before we do any real work, and allows us to unwind the writable unmap check unconditionally as required and to perform a CONFIG_DEBUG_VM_MAPLE_TREE validation unconditionally also. We move a number of things here: 1. We preallocate memory for the iterator before we call the file-backed memory hook, allowing us to exit early and avoid having to perform complicated and error-prone close/free logic. We carefully free iterator state on both success and error paths. 2. The enclosing mmap_region() function handles the mapping_map_writable() logic early. Previously the logic had the mapping_map_writable() at the point of mapping a newly allocated file-backed VMA, and a matching mapping_unmap_writable() on success and error paths. We now do this unconditionally if this is a file-backed, shared writable mapping. If a driver changes the flags to eliminate VM_MAYWRITE, however doing so does not invalidate the seal check we just performed, and we in any case always decrement the counter in the wrapper. We perform a debug assert to ensure a driver does not attempt to do the opposite. 3. We also move arch_validate_flags() up into the mmap_region() function. This is only relevant on arm64 and sparc64, and the check is only meaningful for SPARC with ADI enabled. We explicitly add a warning for this arch if a driver invalidates this check, though the code ought eventually to be fixed to eliminate the need for this. With all of these measures in place, we no longer need to explicitly close the VMA on error paths, as we place all checks which might fail prior to a call to any driver mmap hook. This eliminates an entire class of errors, makes the code easier to reason about and more robust. Link: https://lkml.kernel.org/r/6e0becb36d2f5472053ac5d544c0edfe9b899e25.17302246… Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reported-by: Jann Horn <jannh(a)google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Tested-by: Mark Brown <broonie(a)kernel.org> Cc: Andreas Larsson <andreas(a)gaisler.com> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: David S. Miller <davem(a)davemloft.net> Cc: Helge Deller <deller(a)gmx.de> Cc: James E.J. Bottomley <James.Bottomley(a)HansenPartnership.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Peter Xu <peterx(a)redhat.com> Cc: Will Deacon <will(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/mmap.c b/mm/mmap.c index aee5fa08ae5d..79d541f1502b 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1358,20 +1358,18 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, return do_vmi_munmap(&vmi, mm, start, len, uf, false); } -unsigned long mmap_region(struct file *file, unsigned long addr, +static unsigned long __mmap_region(struct file *file, unsigned long addr, unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, struct list_head *uf) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma = NULL; pgoff_t pglen = PHYS_PFN(len); - struct vm_area_struct *merge; unsigned long charged = 0; struct vma_munmap_struct vms; struct ma_state mas_detach; struct maple_tree mt_detach; unsigned long end = addr + len; - bool writable_file_mapping = false; int error; VMA_ITERATOR(vmi, mm, addr); VMG_STATE(vmg, mm, &vmi, addr, end, vm_flags, pgoff); @@ -1445,28 +1443,26 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vm_flags_init(vma, vm_flags); vma->vm_page_prot = vm_get_page_prot(vm_flags); + if (vma_iter_prealloc(&vmi, vma)) { + error = -ENOMEM; + goto free_vma; + } + if (file) { vma->vm_file = get_file(file); error = mmap_file(file, vma); if (error) - goto unmap_and_free_vma; - - if (vma_is_shared_maywrite(vma)) { - error = mapping_map_writable(file->f_mapping); - if (error) - goto close_and_free_vma; - - writable_file_mapping = true; - } + goto unmap_and_free_file_vma; + /* Drivers cannot alter the address of the VMA. */ + WARN_ON_ONCE(addr != vma->vm_start); /* - * Expansion is handled above, merging is handled below. - * Drivers should not alter the address of the VMA. + * Drivers should not permit writability when previously it was + * disallowed. */ - if (WARN_ON((addr != vma->vm_start))) { - error = -EINVAL; - goto close_and_free_vma; - } + VM_WARN_ON_ONCE(vm_flags != vma->vm_flags && + !(vm_flags & VM_MAYWRITE) && + (vma->vm_flags & VM_MAYWRITE)); vma_iter_config(&vmi, addr, end); /* @@ -1474,6 +1470,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, * vma again as we may succeed this time. */ if (unlikely(vm_flags != vma->vm_flags && vmg.prev)) { + struct vm_area_struct *merge; + vmg.flags = vma->vm_flags; /* If this fails, state is reset ready for a reattempt. */ merge = vma_merge_new_range(&vmg); @@ -1491,7 +1489,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vma = merge; /* Update vm_flags to pick up the change. */ vm_flags = vma->vm_flags; - goto unmap_writable; + goto file_expanded; } vma_iter_config(&vmi, addr, end); } @@ -1500,26 +1498,15 @@ unsigned long mmap_region(struct file *file, unsigned long addr, } else if (vm_flags & VM_SHARED) { error = shmem_zero_setup(vma); if (error) - goto free_vma; + goto free_iter_vma; } else { vma_set_anonymous(vma); } - if (map_deny_write_exec(vma->vm_flags, vma->vm_flags)) { - error = -EACCES; - goto close_and_free_vma; - } - - /* Allow architectures to sanity-check the vm_flags */ - if (!arch_validate_flags(vma->vm_flags)) { - error = -EINVAL; - goto close_and_free_vma; - } - - if (vma_iter_prealloc(&vmi, vma)) { - error = -ENOMEM; - goto close_and_free_vma; - } +#ifdef CONFIG_SPARC64 + /* TODO: Fix SPARC ADI! */ + WARN_ON_ONCE(!arch_validate_flags(vm_flags)); +#endif /* Lock the VMA since it is modified after insertion into VMA tree */ vma_start_write(vma); @@ -1533,10 +1520,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, */ khugepaged_enter_vma(vma, vma->vm_flags); - /* Once vma denies write, undo our temporary denial count */ -unmap_writable: - if (writable_file_mapping) - mapping_unmap_writable(file->f_mapping); +file_expanded: file = vma->vm_file; ksm_add_vma(vma); expanded: @@ -1569,23 +1553,17 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vma_set_page_prot(vma); - validate_mm(mm); return addr; -close_and_free_vma: - vma_close(vma); +unmap_and_free_file_vma: + fput(vma->vm_file); + vma->vm_file = NULL; - if (file || vma->vm_file) { -unmap_and_free_vma: - fput(vma->vm_file); - vma->vm_file = NULL; - - vma_iter_set(&vmi, vma->vm_end); - /* Undo any partial mapping done by a device driver. */ - unmap_region(&vmi.mas, vma, vmg.prev, vmg.next); - } - if (writable_file_mapping) - mapping_unmap_writable(file->f_mapping); + vma_iter_set(&vmi, vma->vm_end); + /* Undo any partial mapping done by a device driver. */ + unmap_region(&vmi.mas, vma, vmg.prev, vmg.next); +free_iter_vma: + vma_iter_free(&vmi); free_vma: vm_area_free(vma); unacct_error: @@ -1595,10 +1573,43 @@ unsigned long mmap_region(struct file *file, unsigned long addr, abort_munmap: vms_abort_munmap_vmas(&vms, &mas_detach); gather_failed: - validate_mm(mm); return error; } +unsigned long mmap_region(struct file *file, unsigned long addr, + unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, + struct list_head *uf) +{ + unsigned long ret; + bool writable_file_mapping = false; + + /* Check to see if MDWE is applicable. */ + if (map_deny_write_exec(vm_flags, vm_flags)) + return -EACCES; + + /* Allow architectures to sanity-check the vm_flags. */ + if (!arch_validate_flags(vm_flags)) + return -EINVAL; + + /* Map writable and ensure this isn't a sealed memfd. */ + if (file && is_shared_maywrite(vm_flags)) { + int error = mapping_map_writable(file->f_mapping); + + if (error) + return error; + writable_file_mapping = true; + } + + ret = __mmap_region(file, addr, len, vm_flags, pgoff, uf); + + /* Clear our write mapping regardless of error. */ + if (writable_file_mapping) + mapping_unmap_writable(file->f_mapping); + + validate_mm(current->mm); + return ret; +} + static int __vm_munmap(unsigned long start, size_t len, bool unlock) { int ret;

5 months, 1 week

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FAILED: patch "[PATCH] mm: unconditionally close VMAs on error" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 4080ef1579b2413435413988d14ac8c68e4d42c8 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111155-roundish-obituary-8322@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 4080ef1579b2413435413988d14ac8c68e4d42c8 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Date: Tue, 29 Oct 2024 18:11:45 +0000 Subject: [PATCH] mm: unconditionally close VMAs on error Incorrect invocation of VMA callbacks when the VMA is no longer in a consistent state is bug prone and risky to perform. With regards to the important vm_ops->close() callback We have gone to great lengths to try to track whether or not we ought to close VMAs. Rather than doing so and risking making a mistake somewhere, instead unconditionally close and reset vma->vm_ops to an empty dummy operations set with a NULL .close operator. We introduce a new function to do so - vma_close() - and simplify existing vms logic which tracked whether we needed to close or not. This simplifies the logic, avoids incorrect double-calling of the .close() callback and allows us to update error paths to simply call vma_close() unconditionally - making VMA closure idempotent. Link: https://lkml.kernel.org/r/28e89dda96f68c505cb6f8e9fc9b57c3e9f74b42.17302246… Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reported-by: Jann Horn <jannh(a)google.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andreas Larsson <andreas(a)gaisler.com> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: David S. Miller <davem(a)davemloft.net> Cc: Helge Deller <deller(a)gmx.de> Cc: James E.J. Bottomley <James.Bottomley(a)HansenPartnership.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Mark Brown <broonie(a)kernel.org> Cc: Peter Xu <peterx(a)redhat.com> Cc: Will Deacon <will(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/internal.h b/mm/internal.h index 4eab2961e69c..64c2eb0b160e 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -135,6 +135,24 @@ static inline int mmap_file(struct file *file, struct vm_area_struct *vma) return err; } +/* + * If the VMA has a close hook then close it, and since closing it might leave + * it in an inconsistent state which makes the use of any hooks suspect, clear + * them down by installing dummy empty hooks. + */ +static inline void vma_close(struct vm_area_struct *vma) +{ + if (vma->vm_ops && vma->vm_ops->close) { + vma->vm_ops->close(vma); + + /* + * The mapping is in an inconsistent state, and no further hooks + * may be invoked upon it. + */ + vma->vm_ops = &vma_dummy_vm_ops; + } +} + #ifdef CONFIG_MMU /* Flags for folio_pte_batch(). */ diff --git a/mm/mmap.c b/mm/mmap.c index 6e3b25f7728f..ac0604f146f6 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1573,8 +1573,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, return addr; close_and_free_vma: - if (file && !vms.closed_vm_ops && vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (file || vma->vm_file) { unmap_and_free_vma: @@ -1934,7 +1933,7 @@ void exit_mmap(struct mm_struct *mm) do { if (vma->vm_flags & VM_ACCOUNT) nr_accounted += vma_pages(vma); - remove_vma(vma, /* unreachable = */ true, /* closed = */ false); + remove_vma(vma, /* unreachable = */ true); count++; cond_resched(); vma = vma_next(&vmi); diff --git a/mm/nommu.c b/mm/nommu.c index f9ccc02458ec..635d028d647b 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -589,8 +589,7 @@ static int delete_vma_from_mm(struct vm_area_struct *vma) */ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) { - if (vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (vma->vm_file) fput(vma->vm_file); put_nommu_region(vma->vm_region); diff --git a/mm/vma.c b/mm/vma.c index b21ffec33f8e..7621384d64cf 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -323,11 +323,10 @@ static bool can_vma_merge_right(struct vma_merge_struct *vmg, /* * Close a vm structure and free it. */ -void remove_vma(struct vm_area_struct *vma, bool unreachable, bool closed) +void remove_vma(struct vm_area_struct *vma, bool unreachable) { might_sleep(); - if (!closed && vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (vma->vm_file) fput(vma->vm_file); mpol_put(vma_policy(vma)); @@ -1115,9 +1114,7 @@ void vms_clean_up_area(struct vma_munmap_struct *vms, vms_clear_ptes(vms, mas_detach, true); mas_set(mas_detach, 0); mas_for_each(mas_detach, vma, ULONG_MAX) - if (vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); - vms->closed_vm_ops = true; + vma_close(vma); } /* @@ -1160,7 +1157,7 @@ void vms_complete_munmap_vmas(struct vma_munmap_struct *vms, /* Remove and clean up vmas */ mas_set(mas_detach, 0); mas_for_each(mas_detach, vma, ULONG_MAX) - remove_vma(vma, /* = */ false, vms->closed_vm_ops); + remove_vma(vma, /* unreachable = */ false); vm_unacct_memory(vms->nr_accounted); validate_mm(mm); @@ -1684,8 +1681,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, return new_vma; out_vma_link: - if (new_vma->vm_ops && new_vma->vm_ops->close) - new_vma->vm_ops->close(new_vma); + vma_close(new_vma); if (new_vma->vm_file) fput(new_vma->vm_file); diff --git a/mm/vma.h b/mm/vma.h index 55457cb68200..75558b5e9c8c 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -42,7 +42,6 @@ struct vma_munmap_struct { int vma_count; /* Number of vmas that will be removed */ bool unlock; /* Unlock after the munmap */ bool clear_ptes; /* If there are outstanding PTE to be cleared */ - bool closed_vm_ops; /* call_mmap() was encountered, so vmas may be closed */ /* 1 byte hole */ unsigned long nr_pages; /* Number of pages being removed */ unsigned long locked_vm; /* Number of locked pages */ @@ -198,7 +197,6 @@ static inline void init_vma_munmap(struct vma_munmap_struct *vms, vms->unmap_start = FIRST_USER_ADDRESS; vms->unmap_end = USER_PGTABLES_CEILING; vms->clear_ptes = false; - vms->closed_vm_ops = false; } #endif @@ -269,7 +267,7 @@ int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf, bool unlock); -void remove_vma(struct vm_area_struct *vma, bool unreachable, bool closed); +void remove_vma(struct vm_area_struct *vma, bool unreachable); void unmap_region(struct ma_state *mas, struct vm_area_struct *vma, struct vm_area_struct *prev, struct vm_area_struct *next);

5 months, 1 week

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FAILED: patch "[PATCH] mm: avoid unsafe VMA hook invocation when error arises on" failed to apply to 6.1-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 3dd6ed34ce1f2356a77fb88edafb5ec96784e3cf # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111143-gigahertz-handrail-961b@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 3dd6ed34ce1f2356a77fb88edafb5ec96784e3cf Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Date: Tue, 29 Oct 2024 18:11:44 +0000 Subject: [PATCH] mm: avoid unsafe VMA hook invocation when error arises on mmap hook Patch series "fix error handling in mmap_region() and refactor (hotfixes)", v4. mmap_region() is somewhat terrifying, with spaghetti-like control flow and numerous means by which issues can arise and incomplete state, memory leaks and other unpleasantness can occur. A large amount of the complexity arises from trying to handle errors late in the process of mapping a VMA, which forms the basis of recently observed issues with resource leaks and observable inconsistent state. This series goes to great lengths to simplify how mmap_region() works and to avoid unwinding errors late on in the process of setting up the VMA for the new mapping, and equally avoids such operations occurring while the VMA is in an inconsistent state. The patches in this series comprise the minimal changes required to resolve existing issues in mmap_region() error handling, in order that they can be hotfixed and backported. There is additionally a follow up series which goes further, separated out from the v1 series and sent and updated separately. This patch (of 5): After an attempted mmap() fails, we are no longer in a situation where we can safely interact with VMA hooks. This is currently not enforced, meaning that we need complicated handling to ensure we do not incorrectly call these hooks. We can avoid the whole issue by treating the VMA as suspect the moment that the file->f_ops->mmap() function reports an error by replacing whatever VMA operations were installed with a dummy empty set of VMA operations. We do so through a new helper function internal to mm - mmap_file() - which is both more logically named than the existing call_mmap() function and correctly isolates handling of the vm_op reassignment to mm. All the existing invocations of call_mmap() outside of mm are ultimately nested within the call_mmap() from mm, which we now replace. It is therefore safe to leave call_mmap() in place as a convenience function (and to avoid churn). The invokers are: ovl_file_operations -> mmap -> ovl_mmap() -> backing_file_mmap() coda_file_operations -> mmap -> coda_file_mmap() shm_file_operations -> shm_mmap() shm_file_operations_huge -> shm_mmap() dma_buf_fops -> dma_buf_mmap_internal -> i915_dmabuf_ops -> i915_gem_dmabuf_mmap() None of these callers interact with vm_ops or mappings in a problematic way on error, quickly exiting out. Link: https://lkml.kernel.org/r/cover.1730224667.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/d41fd763496fd0048a962f3fd9407dc72dd4fd86.17302246… Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reported-by: Jann Horn <jannh(a)google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andreas Larsson <andreas(a)gaisler.com> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: David S. Miller <davem(a)davemloft.net> Cc: Helge Deller <deller(a)gmx.de> Cc: James E.J. Bottomley <James.Bottomley(a)HansenPartnership.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Mark Brown <broonie(a)kernel.org> Cc: Peter Xu <peterx(a)redhat.com> Cc: Will Deacon <will(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/internal.h b/mm/internal.h index 16c1f3cd599e..4eab2961e69c 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -108,6 +108,33 @@ static inline void *folio_raw_mapping(const struct folio *folio) return (void *)(mapping & ~PAGE_MAPPING_FLAGS); } +/* + * This is a file-backed mapping, and is about to be memory mapped - invoke its + * mmap hook and safely handle error conditions. On error, VMA hooks will be + * mutated. + * + * @file: File which backs the mapping. + * @vma: VMA which we are mapping. + * + * Returns: 0 if success, error otherwise. + */ +static inline int mmap_file(struct file *file, struct vm_area_struct *vma) +{ + int err = call_mmap(file, vma); + + if (likely(!err)) + return 0; + + /* + * OK, we tried to call the file hook for mmap(), but an error + * arose. The mapping is in an inconsistent state and we most not invoke + * any further hooks on it. + */ + vma->vm_ops = &vma_dummy_vm_ops; + + return err; +} + #ifdef CONFIG_MMU /* Flags for folio_pte_batch(). */ diff --git a/mm/mmap.c b/mm/mmap.c index 9841b41e3c76..6e3b25f7728f 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1422,7 +1422,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, /* * clear PTEs while the vma is still in the tree so that rmap * cannot race with the freeing later in the truncate scenario. - * This is also needed for call_mmap(), which is why vm_ops + * This is also needed for mmap_file(), which is why vm_ops * close function is called. */ vms_clean_up_area(&vms, &mas_detach); @@ -1447,7 +1447,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, if (file) { vma->vm_file = get_file(file); - error = call_mmap(file, vma); + error = mmap_file(file, vma); if (error) goto unmap_and_free_vma; @@ -1470,7 +1470,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vma_iter_config(&vmi, addr, end); /* - * If vm_flags changed after call_mmap(), we should try merge + * If vm_flags changed after mmap_file(), we should try merge * vma again as we may succeed this time. */ if (unlikely(vm_flags != vma->vm_flags && vmg.prev)) { diff --git a/mm/nommu.c b/mm/nommu.c index 385b0c15add8..f9ccc02458ec 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -885,7 +885,7 @@ static int do_mmap_shared_file(struct vm_area_struct *vma) { int ret; - ret = call_mmap(vma->vm_file, vma); + ret = mmap_file(vma->vm_file, vma); if (ret == 0) { vma->vm_region->vm_top = vma->vm_region->vm_end; return 0; @@ -918,7 +918,7 @@ static int do_mmap_private(struct vm_area_struct *vma, * happy. */ if (capabilities & NOMMU_MAP_DIRECT) { - ret = call_mmap(vma->vm_file, vma); + ret = mmap_file(vma->vm_file, vma); /* shouldn't return success if we're not sharing */ if (WARN_ON_ONCE(!is_nommu_shared_mapping(vma->vm_flags))) ret = -ENOSYS;

5 months, 1 week

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FAILED: patch "[PATCH] mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 5baf8b037debf4ec60108ccfeccb8636d1dbad81 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111139-gladiator-wavy-a9d1@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 5baf8b037debf4ec60108ccfeccb8636d1dbad81 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Date: Tue, 29 Oct 2024 18:11:47 +0000 Subject: [PATCH] mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling Currently MTE is permitted in two circumstances (desiring to use MTE having been specified by the VM_MTE flag) - where MAP_ANONYMOUS is specified, as checked by arch_calc_vm_flag_bits() and actualised by setting the VM_MTE_ALLOWED flag, or if the file backing the mapping is shmem, in which case we set VM_MTE_ALLOWED in shmem_mmap() when the mmap hook is activated in mmap_region(). The function that checks that, if VM_MTE is set, VM_MTE_ALLOWED is also set is the arm64 implementation of arch_validate_flags(). Unfortunately, we intend to refactor mmap_region() to perform this check earlier, meaning that in the case of a shmem backing we will not have invoked shmem_mmap() yet, causing the mapping to fail spuriously. It is inappropriate to set this architecture-specific flag in general mm code anyway, so a sensible resolution of this issue is to instead move the check somewhere else. We resolve this by setting VM_MTE_ALLOWED much earlier in do_mmap(), via the arch_calc_vm_flag_bits() call. This is an appropriate place to do this as we already check for the MAP_ANONYMOUS case here, and the shmem file case is simply a variant of the same idea - we permit RAM-backed memory. This requires a modification to the arch_calc_vm_flag_bits() signature to pass in a pointer to the struct file associated with the mapping, however this is not too egregious as this is only used by two architectures anyway - arm64 and parisc. So this patch performs this adjustment and removes the unnecessary assignment of VM_MTE_ALLOWED in shmem_mmap(). [akpm(a)linux-foundation.org: fix whitespace, per Catalin] Link: https://lkml.kernel.org/r/ec251b20ba1964fb64cf1607d2ad80c47f3873df.17302246… Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Suggested-by: Catalin Marinas <catalin.marinas(a)arm.com> Reported-by: Jann Horn <jannh(a)google.com> Reviewed-by: Catalin Marinas <catalin.marinas(a)arm.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Cc: Andreas Larsson <andreas(a)gaisler.com> Cc: David S. Miller <davem(a)davemloft.net> Cc: Helge Deller <deller(a)gmx.de> Cc: James E.J. Bottomley <James.Bottomley(a)HansenPartnership.com> Cc: Liam R. Howlett <Liam.Howlett(a)oracle.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Mark Brown <broonie(a)kernel.org> Cc: Peter Xu <peterx(a)redhat.com> Cc: Will Deacon <will(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h index 9e39217b4afb..798d965760d4 100644 --- a/arch/arm64/include/asm/mman.h +++ b/arch/arm64/include/asm/mman.h @@ -6,6 +6,8 @@ #ifndef BUILD_VDSO #include <linux/compiler.h> +#include <linux/fs.h> +#include <linux/shmem_fs.h> #include <linux/types.h> static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, @@ -31,19 +33,21 @@ static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, } #define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey) -static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags) +static inline unsigned long arch_calc_vm_flag_bits(struct file *file, + unsigned long flags) { /* * Only allow MTE on anonymous mappings as these are guaranteed to be * backed by tags-capable memory. The vm_flags may be overridden by a * filesystem supporting MTE (RAM-based). */ - if (system_supports_mte() && (flags & MAP_ANONYMOUS)) + if (system_supports_mte() && + ((flags & MAP_ANONYMOUS) || shmem_file(file))) return VM_MTE_ALLOWED; return 0; } -#define arch_calc_vm_flag_bits(flags) arch_calc_vm_flag_bits(flags) +#define arch_calc_vm_flag_bits(file, flags) arch_calc_vm_flag_bits(file, flags) static inline bool arch_validate_prot(unsigned long prot, unsigned long addr __always_unused) diff --git a/arch/parisc/include/asm/mman.h b/arch/parisc/include/asm/mman.h index 89b6beeda0b8..663f587dc789 100644 --- a/arch/parisc/include/asm/mman.h +++ b/arch/parisc/include/asm/mman.h @@ -2,6 +2,7 @@ #ifndef __ASM_MMAN_H__ #define __ASM_MMAN_H__ +#include <linux/fs.h> #include <uapi/asm/mman.h> /* PARISC cannot allow mdwe as it needs writable stacks */ @@ -11,7 +12,7 @@ static inline bool arch_memory_deny_write_exec_supported(void) } #define arch_memory_deny_write_exec_supported arch_memory_deny_write_exec_supported -static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags) +static inline unsigned long arch_calc_vm_flag_bits(struct file *file, unsigned long flags) { /* * The stack on parisc grows upwards, so if userspace requests memory @@ -23,6 +24,6 @@ static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags) return 0; } -#define arch_calc_vm_flag_bits(flags) arch_calc_vm_flag_bits(flags) +#define arch_calc_vm_flag_bits(file, flags) arch_calc_vm_flag_bits(file, flags) #endif /* __ASM_MMAN_H__ */ diff --git a/include/linux/mman.h b/include/linux/mman.h index 8ddca62d6460..a842783ffa62 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -2,6 +2,7 @@ #ifndef _LINUX_MMAN_H #define _LINUX_MMAN_H +#include <linux/fs.h> #include <linux/mm.h> #include <linux/percpu_counter.h> @@ -94,7 +95,7 @@ static inline void vm_unacct_memory(long pages) #endif #ifndef arch_calc_vm_flag_bits -#define arch_calc_vm_flag_bits(flags) 0 +#define arch_calc_vm_flag_bits(file, flags) 0 #endif #ifndef arch_validate_prot @@ -151,13 +152,13 @@ calc_vm_prot_bits(unsigned long prot, unsigned long pkey) * Combine the mmap "flags" argument into "vm_flags" used internally. */ static inline unsigned long -calc_vm_flag_bits(unsigned long flags) +calc_vm_flag_bits(struct file *file, unsigned long flags) { return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) | _calc_vm_trans(flags, MAP_STACK, VM_NOHUGEPAGE) | - arch_calc_vm_flag_bits(flags); + arch_calc_vm_flag_bits(file, flags); } unsigned long vm_commit_limit(void); diff --git a/mm/mmap.c b/mm/mmap.c index ab71d4c3464c..aee5fa08ae5d 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -344,7 +344,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr, * to. we assume access permissions have been handled by the open * of the memory object, so we don't do any here. */ - vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | + vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(file, flags) | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; /* Obtain the address to map to. we verify (or select) it and ensure diff --git a/mm/nommu.c b/mm/nommu.c index 635d028d647b..e9b5f527ab5b 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -842,7 +842,7 @@ static unsigned long determine_vm_flags(struct file *file, { unsigned long vm_flags; - vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags); + vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(file, flags); if (!file) { /* diff --git a/mm/shmem.c b/mm/shmem.c index 4ba1d00fabda..e87f5d6799a7 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2733,9 +2733,6 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma) if (ret) return ret; - /* arm64 - allow memory tagging on RAM-based files */ - vm_flags_set(vma, VM_MTE_ALLOWED); - file_accessed(file); /* This is anonymous shared memory if it is unlinked at the time of mmap */ if (inode->i_nlink)

5 months, 1 week

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FAILED: patch "[PATCH] mm: unconditionally close VMAs on error" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 4080ef1579b2413435413988d14ac8c68e4d42c8 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111156-vascular-splashed-3ffc@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 4080ef1579b2413435413988d14ac8c68e4d42c8 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Date: Tue, 29 Oct 2024 18:11:45 +0000 Subject: [PATCH] mm: unconditionally close VMAs on error Incorrect invocation of VMA callbacks when the VMA is no longer in a consistent state is bug prone and risky to perform. With regards to the important vm_ops->close() callback We have gone to great lengths to try to track whether or not we ought to close VMAs. Rather than doing so and risking making a mistake somewhere, instead unconditionally close and reset vma->vm_ops to an empty dummy operations set with a NULL .close operator. We introduce a new function to do so - vma_close() - and simplify existing vms logic which tracked whether we needed to close or not. This simplifies the logic, avoids incorrect double-calling of the .close() callback and allows us to update error paths to simply call vma_close() unconditionally - making VMA closure idempotent. Link: https://lkml.kernel.org/r/28e89dda96f68c505cb6f8e9fc9b57c3e9f74b42.17302246… Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reported-by: Jann Horn <jannh(a)google.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andreas Larsson <andreas(a)gaisler.com> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: David S. Miller <davem(a)davemloft.net> Cc: Helge Deller <deller(a)gmx.de> Cc: James E.J. Bottomley <James.Bottomley(a)HansenPartnership.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Mark Brown <broonie(a)kernel.org> Cc: Peter Xu <peterx(a)redhat.com> Cc: Will Deacon <will(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/internal.h b/mm/internal.h index 4eab2961e69c..64c2eb0b160e 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -135,6 +135,24 @@ static inline int mmap_file(struct file *file, struct vm_area_struct *vma) return err; } +/* + * If the VMA has a close hook then close it, and since closing it might leave + * it in an inconsistent state which makes the use of any hooks suspect, clear + * them down by installing dummy empty hooks. + */ +static inline void vma_close(struct vm_area_struct *vma) +{ + if (vma->vm_ops && vma->vm_ops->close) { + vma->vm_ops->close(vma); + + /* + * The mapping is in an inconsistent state, and no further hooks + * may be invoked upon it. + */ + vma->vm_ops = &vma_dummy_vm_ops; + } +} + #ifdef CONFIG_MMU /* Flags for folio_pte_batch(). */ diff --git a/mm/mmap.c b/mm/mmap.c index 6e3b25f7728f..ac0604f146f6 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1573,8 +1573,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, return addr; close_and_free_vma: - if (file && !vms.closed_vm_ops && vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (file || vma->vm_file) { unmap_and_free_vma: @@ -1934,7 +1933,7 @@ void exit_mmap(struct mm_struct *mm) do { if (vma->vm_flags & VM_ACCOUNT) nr_accounted += vma_pages(vma); - remove_vma(vma, /* unreachable = */ true, /* closed = */ false); + remove_vma(vma, /* unreachable = */ true); count++; cond_resched(); vma = vma_next(&vmi); diff --git a/mm/nommu.c b/mm/nommu.c index f9ccc02458ec..635d028d647b 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -589,8 +589,7 @@ static int delete_vma_from_mm(struct vm_area_struct *vma) */ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) { - if (vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (vma->vm_file) fput(vma->vm_file); put_nommu_region(vma->vm_region); diff --git a/mm/vma.c b/mm/vma.c index b21ffec33f8e..7621384d64cf 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -323,11 +323,10 @@ static bool can_vma_merge_right(struct vma_merge_struct *vmg, /* * Close a vm structure and free it. */ -void remove_vma(struct vm_area_struct *vma, bool unreachable, bool closed) +void remove_vma(struct vm_area_struct *vma, bool unreachable) { might_sleep(); - if (!closed && vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (vma->vm_file) fput(vma->vm_file); mpol_put(vma_policy(vma)); @@ -1115,9 +1114,7 @@ void vms_clean_up_area(struct vma_munmap_struct *vms, vms_clear_ptes(vms, mas_detach, true); mas_set(mas_detach, 0); mas_for_each(mas_detach, vma, ULONG_MAX) - if (vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); - vms->closed_vm_ops = true; + vma_close(vma); } /* @@ -1160,7 +1157,7 @@ void vms_complete_munmap_vmas(struct vma_munmap_struct *vms, /* Remove and clean up vmas */ mas_set(mas_detach, 0); mas_for_each(mas_detach, vma, ULONG_MAX) - remove_vma(vma, /* = */ false, vms->closed_vm_ops); + remove_vma(vma, /* unreachable = */ false); vm_unacct_memory(vms->nr_accounted); validate_mm(mm); @@ -1684,8 +1681,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, return new_vma; out_vma_link: - if (new_vma->vm_ops && new_vma->vm_ops->close) - new_vma->vm_ops->close(new_vma); + vma_close(new_vma); if (new_vma->vm_file) fput(new_vma->vm_file); diff --git a/mm/vma.h b/mm/vma.h index 55457cb68200..75558b5e9c8c 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -42,7 +42,6 @@ struct vma_munmap_struct { int vma_count; /* Number of vmas that will be removed */ bool unlock; /* Unlock after the munmap */ bool clear_ptes; /* If there are outstanding PTE to be cleared */ - bool closed_vm_ops; /* call_mmap() was encountered, so vmas may be closed */ /* 1 byte hole */ unsigned long nr_pages; /* Number of pages being removed */ unsigned long locked_vm; /* Number of locked pages */ @@ -198,7 +197,6 @@ static inline void init_vma_munmap(struct vma_munmap_struct *vms, vms->unmap_start = FIRST_USER_ADDRESS; vms->unmap_end = USER_PGTABLES_CEILING; vms->clear_ptes = false; - vms->closed_vm_ops = false; } #endif @@ -269,7 +267,7 @@ int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf, bool unlock); -void remove_vma(struct vm_area_struct *vma, bool unreachable, bool closed); +void remove_vma(struct vm_area_struct *vma, bool unreachable); void unmap_region(struct ma_state *mas, struct vm_area_struct *vma, struct vm_area_struct *prev, struct vm_area_struct *next);

5 months, 1 week

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FAILED: patch "[PATCH] mm: avoid unsafe VMA hook invocation when error arises on" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 3dd6ed34ce1f2356a77fb88edafb5ec96784e3cf # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111145-filter-sash-390f@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 3dd6ed34ce1f2356a77fb88edafb5ec96784e3cf Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Date: Tue, 29 Oct 2024 18:11:44 +0000 Subject: [PATCH] mm: avoid unsafe VMA hook invocation when error arises on mmap hook Patch series "fix error handling in mmap_region() and refactor (hotfixes)", v4. mmap_region() is somewhat terrifying, with spaghetti-like control flow and numerous means by which issues can arise and incomplete state, memory leaks and other unpleasantness can occur. A large amount of the complexity arises from trying to handle errors late in the process of mapping a VMA, which forms the basis of recently observed issues with resource leaks and observable inconsistent state. This series goes to great lengths to simplify how mmap_region() works and to avoid unwinding errors late on in the process of setting up the VMA for the new mapping, and equally avoids such operations occurring while the VMA is in an inconsistent state. The patches in this series comprise the minimal changes required to resolve existing issues in mmap_region() error handling, in order that they can be hotfixed and backported. There is additionally a follow up series which goes further, separated out from the v1 series and sent and updated separately. This patch (of 5): After an attempted mmap() fails, we are no longer in a situation where we can safely interact with VMA hooks. This is currently not enforced, meaning that we need complicated handling to ensure we do not incorrectly call these hooks. We can avoid the whole issue by treating the VMA as suspect the moment that the file->f_ops->mmap() function reports an error by replacing whatever VMA operations were installed with a dummy empty set of VMA operations. We do so through a new helper function internal to mm - mmap_file() - which is both more logically named than the existing call_mmap() function and correctly isolates handling of the vm_op reassignment to mm. All the existing invocations of call_mmap() outside of mm are ultimately nested within the call_mmap() from mm, which we now replace. It is therefore safe to leave call_mmap() in place as a convenience function (and to avoid churn). The invokers are: ovl_file_operations -> mmap -> ovl_mmap() -> backing_file_mmap() coda_file_operations -> mmap -> coda_file_mmap() shm_file_operations -> shm_mmap() shm_file_operations_huge -> shm_mmap() dma_buf_fops -> dma_buf_mmap_internal -> i915_dmabuf_ops -> i915_gem_dmabuf_mmap() None of these callers interact with vm_ops or mappings in a problematic way on error, quickly exiting out. Link: https://lkml.kernel.org/r/cover.1730224667.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/d41fd763496fd0048a962f3fd9407dc72dd4fd86.17302246… Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reported-by: Jann Horn <jannh(a)google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andreas Larsson <andreas(a)gaisler.com> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: David S. Miller <davem(a)davemloft.net> Cc: Helge Deller <deller(a)gmx.de> Cc: James E.J. Bottomley <James.Bottomley(a)HansenPartnership.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Mark Brown <broonie(a)kernel.org> Cc: Peter Xu <peterx(a)redhat.com> Cc: Will Deacon <will(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/internal.h b/mm/internal.h index 16c1f3cd599e..4eab2961e69c 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -108,6 +108,33 @@ static inline void *folio_raw_mapping(const struct folio *folio) return (void *)(mapping & ~PAGE_MAPPING_FLAGS); } +/* + * This is a file-backed mapping, and is about to be memory mapped - invoke its + * mmap hook and safely handle error conditions. On error, VMA hooks will be + * mutated. + * + * @file: File which backs the mapping. + * @vma: VMA which we are mapping. + * + * Returns: 0 if success, error otherwise. + */ +static inline int mmap_file(struct file *file, struct vm_area_struct *vma) +{ + int err = call_mmap(file, vma); + + if (likely(!err)) + return 0; + + /* + * OK, we tried to call the file hook for mmap(), but an error + * arose. The mapping is in an inconsistent state and we most not invoke + * any further hooks on it. + */ + vma->vm_ops = &vma_dummy_vm_ops; + + return err; +} + #ifdef CONFIG_MMU /* Flags for folio_pte_batch(). */ diff --git a/mm/mmap.c b/mm/mmap.c index 9841b41e3c76..6e3b25f7728f 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1422,7 +1422,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, /* * clear PTEs while the vma is still in the tree so that rmap * cannot race with the freeing later in the truncate scenario. - * This is also needed for call_mmap(), which is why vm_ops + * This is also needed for mmap_file(), which is why vm_ops * close function is called. */ vms_clean_up_area(&vms, &mas_detach); @@ -1447,7 +1447,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, if (file) { vma->vm_file = get_file(file); - error = call_mmap(file, vma); + error = mmap_file(file, vma); if (error) goto unmap_and_free_vma; @@ -1470,7 +1470,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vma_iter_config(&vmi, addr, end); /* - * If vm_flags changed after call_mmap(), we should try merge + * If vm_flags changed after mmap_file(), we should try merge * vma again as we may succeed this time. */ if (unlikely(vm_flags != vma->vm_flags && vmg.prev)) { diff --git a/mm/nommu.c b/mm/nommu.c index 385b0c15add8..f9ccc02458ec 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -885,7 +885,7 @@ static int do_mmap_shared_file(struct vm_area_struct *vma) { int ret; - ret = call_mmap(vma->vm_file, vma); + ret = mmap_file(vma->vm_file, vma); if (ret == 0) { vma->vm_region->vm_top = vma->vm_region->vm_end; return 0; @@ -918,7 +918,7 @@ static int do_mmap_private(struct vm_area_struct *vma, * happy. */ if (capabilities & NOMMU_MAP_DIRECT) { - ret = call_mmap(vma->vm_file, vma); + ret = mmap_file(vma->vm_file, vma); /* shouldn't return success if we're not sharing */ if (WARN_ON_ONCE(!is_nommu_shared_mapping(vma->vm_flags))) ret = -ENOSYS;

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FAILED: patch "[PATCH] mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 5baf8b037debf4ec60108ccfeccb8636d1dbad81 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111141-married-verbally-bb6c@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 5baf8b037debf4ec60108ccfeccb8636d1dbad81 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Date: Tue, 29 Oct 2024 18:11:47 +0000 Subject: [PATCH] mm: refactor arch_calc_vm_flag_bits() and arm64 MTE handling Currently MTE is permitted in two circumstances (desiring to use MTE having been specified by the VM_MTE flag) - where MAP_ANONYMOUS is specified, as checked by arch_calc_vm_flag_bits() and actualised by setting the VM_MTE_ALLOWED flag, or if the file backing the mapping is shmem, in which case we set VM_MTE_ALLOWED in shmem_mmap() when the mmap hook is activated in mmap_region(). The function that checks that, if VM_MTE is set, VM_MTE_ALLOWED is also set is the arm64 implementation of arch_validate_flags(). Unfortunately, we intend to refactor mmap_region() to perform this check earlier, meaning that in the case of a shmem backing we will not have invoked shmem_mmap() yet, causing the mapping to fail spuriously. It is inappropriate to set this architecture-specific flag in general mm code anyway, so a sensible resolution of this issue is to instead move the check somewhere else. We resolve this by setting VM_MTE_ALLOWED much earlier in do_mmap(), via the arch_calc_vm_flag_bits() call. This is an appropriate place to do this as we already check for the MAP_ANONYMOUS case here, and the shmem file case is simply a variant of the same idea - we permit RAM-backed memory. This requires a modification to the arch_calc_vm_flag_bits() signature to pass in a pointer to the struct file associated with the mapping, however this is not too egregious as this is only used by two architectures anyway - arm64 and parisc. So this patch performs this adjustment and removes the unnecessary assignment of VM_MTE_ALLOWED in shmem_mmap(). [akpm(a)linux-foundation.org: fix whitespace, per Catalin] Link: https://lkml.kernel.org/r/ec251b20ba1964fb64cf1607d2ad80c47f3873df.17302246… Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Suggested-by: Catalin Marinas <catalin.marinas(a)arm.com> Reported-by: Jann Horn <jannh(a)google.com> Reviewed-by: Catalin Marinas <catalin.marinas(a)arm.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Cc: Andreas Larsson <andreas(a)gaisler.com> Cc: David S. Miller <davem(a)davemloft.net> Cc: Helge Deller <deller(a)gmx.de> Cc: James E.J. Bottomley <James.Bottomley(a)HansenPartnership.com> Cc: Liam R. Howlett <Liam.Howlett(a)oracle.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Mark Brown <broonie(a)kernel.org> Cc: Peter Xu <peterx(a)redhat.com> Cc: Will Deacon <will(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/arch/arm64/include/asm/mman.h b/arch/arm64/include/asm/mman.h index 9e39217b4afb..798d965760d4 100644 --- a/arch/arm64/include/asm/mman.h +++ b/arch/arm64/include/asm/mman.h @@ -6,6 +6,8 @@ #ifndef BUILD_VDSO #include <linux/compiler.h> +#include <linux/fs.h> +#include <linux/shmem_fs.h> #include <linux/types.h> static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, @@ -31,19 +33,21 @@ static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot, } #define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey) -static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags) +static inline unsigned long arch_calc_vm_flag_bits(struct file *file, + unsigned long flags) { /* * Only allow MTE on anonymous mappings as these are guaranteed to be * backed by tags-capable memory. The vm_flags may be overridden by a * filesystem supporting MTE (RAM-based). */ - if (system_supports_mte() && (flags & MAP_ANONYMOUS)) + if (system_supports_mte() && + ((flags & MAP_ANONYMOUS) || shmem_file(file))) return VM_MTE_ALLOWED; return 0; } -#define arch_calc_vm_flag_bits(flags) arch_calc_vm_flag_bits(flags) +#define arch_calc_vm_flag_bits(file, flags) arch_calc_vm_flag_bits(file, flags) static inline bool arch_validate_prot(unsigned long prot, unsigned long addr __always_unused) diff --git a/arch/parisc/include/asm/mman.h b/arch/parisc/include/asm/mman.h index 89b6beeda0b8..663f587dc789 100644 --- a/arch/parisc/include/asm/mman.h +++ b/arch/parisc/include/asm/mman.h @@ -2,6 +2,7 @@ #ifndef __ASM_MMAN_H__ #define __ASM_MMAN_H__ +#include <linux/fs.h> #include <uapi/asm/mman.h> /* PARISC cannot allow mdwe as it needs writable stacks */ @@ -11,7 +12,7 @@ static inline bool arch_memory_deny_write_exec_supported(void) } #define arch_memory_deny_write_exec_supported arch_memory_deny_write_exec_supported -static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags) +static inline unsigned long arch_calc_vm_flag_bits(struct file *file, unsigned long flags) { /* * The stack on parisc grows upwards, so if userspace requests memory @@ -23,6 +24,6 @@ static inline unsigned long arch_calc_vm_flag_bits(unsigned long flags) return 0; } -#define arch_calc_vm_flag_bits(flags) arch_calc_vm_flag_bits(flags) +#define arch_calc_vm_flag_bits(file, flags) arch_calc_vm_flag_bits(file, flags) #endif /* __ASM_MMAN_H__ */ diff --git a/include/linux/mman.h b/include/linux/mman.h index 8ddca62d6460..a842783ffa62 100644 --- a/include/linux/mman.h +++ b/include/linux/mman.h @@ -2,6 +2,7 @@ #ifndef _LINUX_MMAN_H #define _LINUX_MMAN_H +#include <linux/fs.h> #include <linux/mm.h> #include <linux/percpu_counter.h> @@ -94,7 +95,7 @@ static inline void vm_unacct_memory(long pages) #endif #ifndef arch_calc_vm_flag_bits -#define arch_calc_vm_flag_bits(flags) 0 +#define arch_calc_vm_flag_bits(file, flags) 0 #endif #ifndef arch_validate_prot @@ -151,13 +152,13 @@ calc_vm_prot_bits(unsigned long prot, unsigned long pkey) * Combine the mmap "flags" argument into "vm_flags" used internally. */ static inline unsigned long -calc_vm_flag_bits(unsigned long flags) +calc_vm_flag_bits(struct file *file, unsigned long flags) { return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) | _calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) | _calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) | _calc_vm_trans(flags, MAP_STACK, VM_NOHUGEPAGE) | - arch_calc_vm_flag_bits(flags); + arch_calc_vm_flag_bits(file, flags); } unsigned long vm_commit_limit(void); diff --git a/mm/mmap.c b/mm/mmap.c index ab71d4c3464c..aee5fa08ae5d 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -344,7 +344,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr, * to. we assume access permissions have been handled by the open * of the memory object, so we don't do any here. */ - vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | + vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(file, flags) | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; /* Obtain the address to map to. we verify (or select) it and ensure diff --git a/mm/nommu.c b/mm/nommu.c index 635d028d647b..e9b5f527ab5b 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -842,7 +842,7 @@ static unsigned long determine_vm_flags(struct file *file, { unsigned long vm_flags; - vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags); + vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(file, flags); if (!file) { /* diff --git a/mm/shmem.c b/mm/shmem.c index 4ba1d00fabda..e87f5d6799a7 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2733,9 +2733,6 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma) if (ret) return ret; - /* arm64 - allow memory tagging on RAM-based files */ - vm_flags_set(vma, VM_MTE_ALLOWED); - file_accessed(file); /* This is anonymous shared memory if it is unlinked at the time of mmap */ if (inode->i_nlink)

5 months, 1 week

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FAILED: patch "[PATCH] mm: unconditionally close VMAs on error" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 4080ef1579b2413435413988d14ac8c68e4d42c8 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111157-muster-engaging-dad6@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 4080ef1579b2413435413988d14ac8c68e4d42c8 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Date: Tue, 29 Oct 2024 18:11:45 +0000 Subject: [PATCH] mm: unconditionally close VMAs on error Incorrect invocation of VMA callbacks when the VMA is no longer in a consistent state is bug prone and risky to perform. With regards to the important vm_ops->close() callback We have gone to great lengths to try to track whether or not we ought to close VMAs. Rather than doing so and risking making a mistake somewhere, instead unconditionally close and reset vma->vm_ops to an empty dummy operations set with a NULL .close operator. We introduce a new function to do so - vma_close() - and simplify existing vms logic which tracked whether we needed to close or not. This simplifies the logic, avoids incorrect double-calling of the .close() callback and allows us to update error paths to simply call vma_close() unconditionally - making VMA closure idempotent. Link: https://lkml.kernel.org/r/28e89dda96f68c505cb6f8e9fc9b57c3e9f74b42.17302246… Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reported-by: Jann Horn <jannh(a)google.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andreas Larsson <andreas(a)gaisler.com> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: David S. Miller <davem(a)davemloft.net> Cc: Helge Deller <deller(a)gmx.de> Cc: James E.J. Bottomley <James.Bottomley(a)HansenPartnership.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Mark Brown <broonie(a)kernel.org> Cc: Peter Xu <peterx(a)redhat.com> Cc: Will Deacon <will(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/internal.h b/mm/internal.h index 4eab2961e69c..64c2eb0b160e 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -135,6 +135,24 @@ static inline int mmap_file(struct file *file, struct vm_area_struct *vma) return err; } +/* + * If the VMA has a close hook then close it, and since closing it might leave + * it in an inconsistent state which makes the use of any hooks suspect, clear + * them down by installing dummy empty hooks. + */ +static inline void vma_close(struct vm_area_struct *vma) +{ + if (vma->vm_ops && vma->vm_ops->close) { + vma->vm_ops->close(vma); + + /* + * The mapping is in an inconsistent state, and no further hooks + * may be invoked upon it. + */ + vma->vm_ops = &vma_dummy_vm_ops; + } +} + #ifdef CONFIG_MMU /* Flags for folio_pte_batch(). */ diff --git a/mm/mmap.c b/mm/mmap.c index 6e3b25f7728f..ac0604f146f6 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1573,8 +1573,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, return addr; close_and_free_vma: - if (file && !vms.closed_vm_ops && vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (file || vma->vm_file) { unmap_and_free_vma: @@ -1934,7 +1933,7 @@ void exit_mmap(struct mm_struct *mm) do { if (vma->vm_flags & VM_ACCOUNT) nr_accounted += vma_pages(vma); - remove_vma(vma, /* unreachable = */ true, /* closed = */ false); + remove_vma(vma, /* unreachable = */ true); count++; cond_resched(); vma = vma_next(&vmi); diff --git a/mm/nommu.c b/mm/nommu.c index f9ccc02458ec..635d028d647b 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -589,8 +589,7 @@ static int delete_vma_from_mm(struct vm_area_struct *vma) */ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) { - if (vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (vma->vm_file) fput(vma->vm_file); put_nommu_region(vma->vm_region); diff --git a/mm/vma.c b/mm/vma.c index b21ffec33f8e..7621384d64cf 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -323,11 +323,10 @@ static bool can_vma_merge_right(struct vma_merge_struct *vmg, /* * Close a vm structure and free it. */ -void remove_vma(struct vm_area_struct *vma, bool unreachable, bool closed) +void remove_vma(struct vm_area_struct *vma, bool unreachable) { might_sleep(); - if (!closed && vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); + vma_close(vma); if (vma->vm_file) fput(vma->vm_file); mpol_put(vma_policy(vma)); @@ -1115,9 +1114,7 @@ void vms_clean_up_area(struct vma_munmap_struct *vms, vms_clear_ptes(vms, mas_detach, true); mas_set(mas_detach, 0); mas_for_each(mas_detach, vma, ULONG_MAX) - if (vma->vm_ops && vma->vm_ops->close) - vma->vm_ops->close(vma); - vms->closed_vm_ops = true; + vma_close(vma); } /* @@ -1160,7 +1157,7 @@ void vms_complete_munmap_vmas(struct vma_munmap_struct *vms, /* Remove and clean up vmas */ mas_set(mas_detach, 0); mas_for_each(mas_detach, vma, ULONG_MAX) - remove_vma(vma, /* = */ false, vms->closed_vm_ops); + remove_vma(vma, /* unreachable = */ false); vm_unacct_memory(vms->nr_accounted); validate_mm(mm); @@ -1684,8 +1681,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, return new_vma; out_vma_link: - if (new_vma->vm_ops && new_vma->vm_ops->close) - new_vma->vm_ops->close(new_vma); + vma_close(new_vma); if (new_vma->vm_file) fput(new_vma->vm_file); diff --git a/mm/vma.h b/mm/vma.h index 55457cb68200..75558b5e9c8c 100644 --- a/mm/vma.h +++ b/mm/vma.h @@ -42,7 +42,6 @@ struct vma_munmap_struct { int vma_count; /* Number of vmas that will be removed */ bool unlock; /* Unlock after the munmap */ bool clear_ptes; /* If there are outstanding PTE to be cleared */ - bool closed_vm_ops; /* call_mmap() was encountered, so vmas may be closed */ /* 1 byte hole */ unsigned long nr_pages; /* Number of pages being removed */ unsigned long locked_vm; /* Number of locked pages */ @@ -198,7 +197,6 @@ static inline void init_vma_munmap(struct vma_munmap_struct *vms, vms->unmap_start = FIRST_USER_ADDRESS; vms->unmap_end = USER_PGTABLES_CEILING; vms->clear_ptes = false; - vms->closed_vm_ops = false; } #endif @@ -269,7 +267,7 @@ int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf, bool unlock); -void remove_vma(struct vm_area_struct *vma, bool unreachable, bool closed); +void remove_vma(struct vm_area_struct *vma, bool unreachable); void unmap_region(struct ma_state *mas, struct vm_area_struct *vma, struct vm_area_struct *prev, struct vm_area_struct *next);

5 months, 1 week

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FAILED: patch "[PATCH] mm: avoid unsafe VMA hook invocation when error arises on" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y git checkout FETCH_HEAD git cherry-pick -x 3dd6ed34ce1f2356a77fb88edafb5ec96784e3cf # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2024111146-visiting-designing-ea20@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 3dd6ed34ce1f2356a77fb88edafb5ec96784e3cf Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Date: Tue, 29 Oct 2024 18:11:44 +0000 Subject: [PATCH] mm: avoid unsafe VMA hook invocation when error arises on mmap hook Patch series "fix error handling in mmap_region() and refactor (hotfixes)", v4. mmap_region() is somewhat terrifying, with spaghetti-like control flow and numerous means by which issues can arise and incomplete state, memory leaks and other unpleasantness can occur. A large amount of the complexity arises from trying to handle errors late in the process of mapping a VMA, which forms the basis of recently observed issues with resource leaks and observable inconsistent state. This series goes to great lengths to simplify how mmap_region() works and to avoid unwinding errors late on in the process of setting up the VMA for the new mapping, and equally avoids such operations occurring while the VMA is in an inconsistent state. The patches in this series comprise the minimal changes required to resolve existing issues in mmap_region() error handling, in order that they can be hotfixed and backported. There is additionally a follow up series which goes further, separated out from the v1 series and sent and updated separately. This patch (of 5): After an attempted mmap() fails, we are no longer in a situation where we can safely interact with VMA hooks. This is currently not enforced, meaning that we need complicated handling to ensure we do not incorrectly call these hooks. We can avoid the whole issue by treating the VMA as suspect the moment that the file->f_ops->mmap() function reports an error by replacing whatever VMA operations were installed with a dummy empty set of VMA operations. We do so through a new helper function internal to mm - mmap_file() - which is both more logically named than the existing call_mmap() function and correctly isolates handling of the vm_op reassignment to mm. All the existing invocations of call_mmap() outside of mm are ultimately nested within the call_mmap() from mm, which we now replace. It is therefore safe to leave call_mmap() in place as a convenience function (and to avoid churn). The invokers are: ovl_file_operations -> mmap -> ovl_mmap() -> backing_file_mmap() coda_file_operations -> mmap -> coda_file_mmap() shm_file_operations -> shm_mmap() shm_file_operations_huge -> shm_mmap() dma_buf_fops -> dma_buf_mmap_internal -> i915_dmabuf_ops -> i915_gem_dmabuf_mmap() None of these callers interact with vm_ops or mappings in a problematic way on error, quickly exiting out. Link: https://lkml.kernel.org/r/cover.1730224667.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/d41fd763496fd0048a962f3fd9407dc72dd4fd86.17302246… Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Reported-by: Jann Horn <jannh(a)google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett(a)oracle.com> Reviewed-by: Vlastimil Babka <vbabka(a)suse.cz> Reviewed-by: Jann Horn <jannh(a)google.com> Cc: Andreas Larsson <andreas(a)gaisler.com> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: David S. Miller <davem(a)davemloft.net> Cc: Helge Deller <deller(a)gmx.de> Cc: James E.J. Bottomley <James.Bottomley(a)HansenPartnership.com> Cc: Linus Torvalds <torvalds(a)linux-foundation.org> Cc: Mark Brown <broonie(a)kernel.org> Cc: Peter Xu <peterx(a)redhat.com> Cc: Will Deacon <will(a)kernel.org> Cc: <stable(a)vger.kernel.org> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> diff --git a/mm/internal.h b/mm/internal.h index 16c1f3cd599e..4eab2961e69c 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -108,6 +108,33 @@ static inline void *folio_raw_mapping(const struct folio *folio) return (void *)(mapping & ~PAGE_MAPPING_FLAGS); } +/* + * This is a file-backed mapping, and is about to be memory mapped - invoke its + * mmap hook and safely handle error conditions. On error, VMA hooks will be + * mutated. + * + * @file: File which backs the mapping. + * @vma: VMA which we are mapping. + * + * Returns: 0 if success, error otherwise. + */ +static inline int mmap_file(struct file *file, struct vm_area_struct *vma) +{ + int err = call_mmap(file, vma); + + if (likely(!err)) + return 0; + + /* + * OK, we tried to call the file hook for mmap(), but an error + * arose. The mapping is in an inconsistent state and we most not invoke + * any further hooks on it. + */ + vma->vm_ops = &vma_dummy_vm_ops; + + return err; +} + #ifdef CONFIG_MMU /* Flags for folio_pte_batch(). */ diff --git a/mm/mmap.c b/mm/mmap.c index 9841b41e3c76..6e3b25f7728f 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1422,7 +1422,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, /* * clear PTEs while the vma is still in the tree so that rmap * cannot race with the freeing later in the truncate scenario. - * This is also needed for call_mmap(), which is why vm_ops + * This is also needed for mmap_file(), which is why vm_ops * close function is called. */ vms_clean_up_area(&vms, &mas_detach); @@ -1447,7 +1447,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, if (file) { vma->vm_file = get_file(file); - error = call_mmap(file, vma); + error = mmap_file(file, vma); if (error) goto unmap_and_free_vma; @@ -1470,7 +1470,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr, vma_iter_config(&vmi, addr, end); /* - * If vm_flags changed after call_mmap(), we should try merge + * If vm_flags changed after mmap_file(), we should try merge * vma again as we may succeed this time. */ if (unlikely(vm_flags != vma->vm_flags && vmg.prev)) { diff --git a/mm/nommu.c b/mm/nommu.c index 385b0c15add8..f9ccc02458ec 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -885,7 +885,7 @@ static int do_mmap_shared_file(struct vm_area_struct *vma) { int ret; - ret = call_mmap(vma->vm_file, vma); + ret = mmap_file(vma->vm_file, vma); if (ret == 0) { vma->vm_region->vm_top = vma->vm_region->vm_end; return 0; @@ -918,7 +918,7 @@ static int do_mmap_private(struct vm_area_struct *vma, * happy. */ if (capabilities & NOMMU_MAP_DIRECT) { - ret = call_mmap(vma->vm_file, vma); + ret = mmap_file(vma->vm_file, vma); /* shouldn't return success if we're not sharing */ if (WARN_ON_ONCE(!is_nommu_shared_mapping(vma->vm_flags))) ret = -ENOSYS;

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[PATCH v1] drm/bridge: tc358768: Fix DSI command tx

by Francesco Dolcini

From: Francesco Dolcini <francesco.dolcini(a)toradex.com> Wait for the command transmission to be completed in the DSI transfer function polling for the dc_start bit to go back to idle state after the transmission is started. This is documented in the datasheet and failures to do so lead to commands corruption. Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver") Cc: stable(a)vger.kernel.org Signed-off-by: Francesco Dolcini <francesco.dolcini(a)toradex.com> --- drivers/gpu/drm/bridge/tc358768.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c index 0e8813278a2f..bb1750a3dab0 100644 --- a/drivers/gpu/drm/bridge/tc358768.c +++ b/drivers/gpu/drm/bridge/tc358768.c @@ -125,6 +125,9 @@ #define TC358768_DSI_CONFW_MODE_CLR (6 << 29) #define TC358768_DSI_CONFW_ADDR_DSI_CONTROL (0x3 << 24) +/* TC358768_DSICMD_TX (0x0600) register */ +#define TC358768_DSI_CMDTX_DC_START BIT(0) + static const char * const tc358768_supplies[] = { "vddc", "vddmipi", "vddio" }; @@ -229,6 +232,21 @@ static void tc358768_update_bits(struct tc358768_priv *priv, u32 reg, u32 mask, tc358768_write(priv, reg, tmp); } +static void tc358768_dsicmd_tx(struct tc358768_priv *priv) +{ + u32 val; + + /* start transfer */ + tc358768_write(priv, TC358768_DSICMD_TX, TC358768_DSI_CMDTX_DC_START); + if (priv->error) + return; + + /* wait transfer completion */ + priv->error = regmap_read_poll_timeout(priv->regmap, TC358768_DSICMD_TX, val, + (val & TC358768_DSI_CMDTX_DC_START) == 0, + 100, 100000); +} + static int tc358768_sw_reset(struct tc358768_priv *priv) { /* Assert Reset */ @@ -516,8 +534,7 @@ static ssize_t tc358768_dsi_host_transfer(struct mipi_dsi_host *host, } } - /* start transfer */ - tc358768_write(priv, TC358768_DSICMD_TX, 1); + tc358768_dsicmd_tx(priv); ret = tc358768_clear_error(priv); if (ret) -- 2.39.5

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