kernel/linux.git/lib/scatterlist.c, branch v6.6.142

lib/scatterlist: fix temp buffer in extract_user_to_sg()

2026-05-17T15:13:41+00:00

commit 118cf3f55975352ac357fb194405031458186819 upstream. Instead of allocating a temporary buffer for extracted user pages extract_user_to_sg() uses the end of the to be filled scatterlist as a temporary buffer. Fix the calculation of the start address if the scatterlist already contains elements. The unused space starts at sgtable->sgl + sgtable->nents not directly at sgtable->nents and the temporary buffer is placed at the end of this unused space. A subsequent commit will add kunit test cases that demonstrate that the patch is necessary. Pointed out by sashiko.dev on a previous iteration of this series. Link: https://lkml.kernel.org/r/20260326214905.818170-3-lk@c--e.de Fixes: 018584697533 ("netfs: Add a function to extract an iterator into a scatterlist") Signed-off-by: Christian A. Ehrhardt Cc: David Howells Cc: David Gow Cc: Kees Cook Cc: Petr Mladek Cc: [v6.5+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

lib/scatterlist: fix length calculations in extract_kvec_to_sg

2026-05-17T15:13:41+00:00

commit 07b7d66e65d9cfe6b9c2c34aa22cfcaac37a5c45 upstream. Patch series "Fix bugs in extract_iter_to_sg()", v3. Fix bugs in the kvec and user variants of extract_iter_to_sg. This series is growing due to useful remarks made by sashiko.dev. The main bugs are: - The length for an sglist entry when extracting from a kvec can exceed the number of bytes in the page. This is obviously not intended. - When extracting a user buffer the sglist is temporarily used as a scratch buffer for extracted page pointers. If the sglist already contains some elements this scratch buffer could overlap with existing entries in the sglist. The series adds test cases to the kunit_iov_iter test that demonstrate all of these bugs. Additionally, there is a memory leak fix for the test itself. The bugs were orignally introduced into kernel v6.3 where the function lived in fs/netfs/iterator.c. It was later moved to lib/scatterlist.c in v6.5. Thus the actual fix is only marked for backports to v6.5+. This patch (of 5): When extracting from a kvec to a scatterlist, do not cross page boundaries. The required length was already calculated but not used as intended. Adjust the copied length if the loop runs out of sglist entries without extracting everything. While there, return immediately from extract_iter_to_sg if there are no sglist entries at all. A subsequent commit will add kunit test cases that demonstrate that the patch is necessary. Link: https://lkml.kernel.org/r/20260326214905.818170-1-lk@c--e.de Link: https://lkml.kernel.org/r/20260326214905.818170-2-lk@c--e.de Fixes: 018584697533 ("netfs: Add a function to extract an iterator into a scatterlist") Signed-off-by: Christian A. Ehrhardt Cc: David Gow Cc: David Howells Cc: Kees Cook Cc: Petr Mladek Cc: [v6.5+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

Fix a potential infinite loop in extract_user_to_sg()

2024-05-17T10:02:02+00:00

[ Upstream commit 6a30653b604aaad1bf0f2e74b068ceb8b6fc7aea ] Fix extract_user_to_sg() so that it will break out of the loop if iov_iter_extract_pages() returns 0 rather than looping around forever. [Note that I've included two fixes lines as the function got moved to a different file and renamed] Fixes: 85dd2c8ff368 ("netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator") Fixes: f5f82cd18732 ("Move netfs_extract_iter_to_sg() to lib/scatterlist.c") Signed-off-by: David Howells cc: Jeff Layton cc: Steve French cc: Herbert Xu cc: netfs@lists.linux.dev Link: https://lore.kernel.org/r/1967121.1714034372@warthog.procyon.org.uk Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

scatterlist: add missing function params to kernel-doc

2023-09-19T20:21:33+00:00

Describe missing function parameters to prevent kernel-doc warnings: lib/scatterlist.c:288: warning: Function parameter or member 'first_chunk' not described in '__sg_alloc_table' lib/scatterlist.c:800: warning: Function parameter or member 'flags' not described in 'sg_miter_start' Link: https://lkml.kernel.org/r/20230912060848.4673-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap Signed-off-by: Andrew Morton

crypto, cifs: fix error handling in extract_iter_to_sg()

2023-08-04T20:03:40+00:00

Fix error handling in extract_iter_to_sg(). Pages need to be unpinned, not put in extract_user_to_sg() when handling IOVEC/UBUF sources. The bug may result in a warning like the following: WARNING: CPU: 1 PID: 20384 at mm/gup.c:229 __lse_atomic_add arch/arm64/include/asm/atomic_lse.h:27 [inline] WARNING: CPU: 1 PID: 20384 at mm/gup.c:229 arch_atomic_add arch/arm64/include/asm/atomic.h:28 [inline] WARNING: CPU: 1 PID: 20384 at mm/gup.c:229 raw_atomic_add include/linux/atomic/atomic-arch-fallback.h:537 [inline] WARNING: CPU: 1 PID: 20384 at mm/gup.c:229 atomic_add include/linux/atomic/atomic-instrumented.h:105 [inline] WARNING: CPU: 1 PID: 20384 at mm/gup.c:229 try_grab_page+0x108/0x160 mm/gup.c:252 ... pc : try_grab_page+0x108/0x160 mm/gup.c:229 lr : follow_page_pte+0x174/0x3e4 mm/gup.c:651 ... Call trace: __lse_atomic_add arch/arm64/include/asm/atomic_lse.h:27 [inline] arch_atomic_add arch/arm64/include/asm/atomic.h:28 [inline] raw_atomic_add include/linux/atomic/atomic-arch-fallback.h:537 [inline] atomic_add include/linux/atomic/atomic-instrumented.h:105 [inline] try_grab_page+0x108/0x160 mm/gup.c:252 follow_pmd_mask mm/gup.c:734 [inline] follow_pud_mask mm/gup.c:765 [inline] follow_p4d_mask mm/gup.c:782 [inline] follow_page_mask+0x12c/0x2e4 mm/gup.c:839 __get_user_pages+0x174/0x30c mm/gup.c:1217 __get_user_pages_locked mm/gup.c:1448 [inline] __gup_longterm_locked+0x94/0x8f4 mm/gup.c:2142 internal_get_user_pages_fast+0x970/0xb60 mm/gup.c:3140 pin_user_pages_fast+0x4c/0x60 mm/gup.c:3246 iov_iter_extract_user_pages lib/iov_iter.c:1768 [inline] iov_iter_extract_pages+0xc8/0x54c lib/iov_iter.c:1831 extract_user_to_sg lib/scatterlist.c:1123 [inline] extract_iter_to_sg lib/scatterlist.c:1349 [inline] extract_iter_to_sg+0x26c/0x6fc lib/scatterlist.c:1339 hash_sendmsg+0xc0/0x43c crypto/algif_hash.c:117 sock_sendmsg_nosec net/socket.c:725 [inline] sock_sendmsg+0x54/0x60 net/socket.c:748 ____sys_sendmsg+0x270/0x2ac net/socket.c:2494 ___sys_sendmsg+0x80/0xdc net/socket.c:2548 __sys_sendmsg+0x68/0xc4 net/socket.c:2577 __do_sys_sendmsg net/socket.c:2586 [inline] __se_sys_sendmsg net/socket.c:2584 [inline] __arm64_sys_sendmsg+0x24/0x30 net/socket.c:2584 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline] invoke_syscall+0x48/0x114 arch/arm64/kernel/syscall.c:52 el0_svc_common.constprop.0+0x44/0xe4 arch/arm64/kernel/syscall.c:142 do_el0_svc+0x38/0xa4 arch/arm64/kernel/syscall.c:191 el0_svc+0x2c/0xb0 arch/arm64/kernel/entry-common.c:647 el0t_64_sync_handler+0xc0/0xc4 arch/arm64/kernel/entry-common.c:665 el0t_64_sync+0x19c/0x1a0 arch/arm64/kernel/entry.S:591 Link: https://lkml.kernel.org/r/20571.1690369076@warthog.procyon.org.uk Fixes: 018584697533 ("netfs: Add a function to extract an iterator into a scatterlist") Reported-by: syzbot+9b82859567f2e50c123e@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-mm/000000000000273d0105ff97bf56@google.com/ Signed-off-by: David Howells Reviewed-by: David Hildenbrand Acked-by: Steve French Cc: Sven Schnelle Cc: Herbert Xu Cc: Jeff Layton Cc: Shyam Prasad N Cc: Rohith Surabattula Cc: Jens Axboe Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Matthew Wilcox Cc: Signed-off-by: Andrew Morton

Merge tag 'asm-generic-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2023-07-06T17:06:04+00:00

Pull asm-generic updates from Arnd Bergmann: "These are cleanups for architecture specific header files: - the comments in include/linux/syscalls.h have gone out of sync and are really pointless, so these get removed - The asm/bitsperlong.h header no longer needs to be architecture specific on modern compilers, so use a generic version for newer architectures that use new enough userspace compilers - A cleanup for virt_to_pfn/virt_to_bus to have proper type checking, forcing the use of pointers" * tag 'asm-generic-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: syscalls: Remove file path comments from headers tools arch: Remove uapi bitsperlong.h of hexagon and microblaze asm-generic: Unify uapi bitsperlong.h for arm64, riscv and loongarch m68k/mm: Make pfn accessors static inlines arm64: memory: Make virt_to_pfn() a static inline ARM: mm: Make virt_to_pfn() a static inline asm-generic/page.h: Make pfn accessors static inlines xen/netback: Pass (void *) to virt_to_page() netfs: Pass a pointer to virt_to_page() cifs: Pass a pointer to virt_to_page() in cifsglob cifs: Pass a pointer to virt_to_page() riscv: mm: init: Pass a pointer to virt_to_page() ARC: init: Pass a pointer to virt_to_pfn() in init m68k: Pass a pointer to virt_to_pfn() virt_to_page() fs/proc/kcore.c: Pass a pointer to virt_addr_valid()

Move netfs_extract_iter_to_sg() to lib/scatterlist.c

2023-06-08T11:42:33+00:00

Move netfs_extract_iter_to_sg() to lib/scatterlist.c as it's going to be used by more than just network filesystems (AF_ALG, for example). Signed-off-by: David Howells cc: Jeff Layton cc: Steve French cc: Shyam Prasad N cc: Rohith Surabattula cc: Jens Axboe cc: Herbert Xu cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Matthew Wilcox cc: linux-crypto@vger.kernel.org cc: linux-cachefs@redhat.com cc: linux-cifs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org cc: netdev@vger.kernel.org Signed-off-by: Paolo Abeni

lib/scatterlist: Fix to calculate the last_pg properly

2023-01-16T16:08:31+00:00

The last_pg is wrong, it is actually the first page of the last scatterlist element. To get the last page of the last scatterlist element we have to add prv->length. So it is checking mergability against the wrong page, Further, a SG element is not guaranteed to end on a page boundary, so we have to check the sub page location also for merge eligibility. Fix the above by checking physical contiguity based on PFNs, compute the actual last page and then call pages_are_mergable(). Fixes: 1567b49d1a40 ("lib/scatterlist: add check when merging zone device pages") Link: https://lore.kernel.org/r/20230111101054.188136-1-yishaih@nvidia.com Reported-by: Jason Gunthorpe Signed-off-by: Yishai Hadas Reviewed-by: Chaitanya Kulkarni Signed-off-by: Jason Gunthorpe

lib/scatterlist: Fix to merge contiguous pages into the last SG properly

2023-01-05T20:01:05+00:00

When sg_alloc_append_table_from_pages() calls to pages_are_mergeable() in its 'sgt_append->prv' flow to check whether it can merge contiguous pages into the last SG, it passes the page arguments in the wrong order. The first parameter should be the next candidate page to be merged to the last page and not the opposite. The current code leads to a corrupted SG which resulted in OOPs and unexpected errors when non-contiguous pages are merged wrongly. Fix to pass the page parameters in the right order. Fixes: 1567b49d1a40 ("lib/scatterlist: add check when merging zone device pages") Link: https://lore.kernel.org/r/20230105112339.107969-1-yishaih@nvidia.com Signed-off-by: Yishai Hadas Reviewed-by: Jason Gunthorpe Reviewed-by: Logan Gunthorpe Signed-off-by: Jason Gunthorpe

lib/scatterlist: add check when merging zone device pages

2022-11-09T18:29:21+00:00

Consecutive zone device pages should not be merged into the same sgl or bvec segment with other types of pages or if they belong to different pgmaps. Otherwise getting the pgmap of a given segment is not possible without scanning the entire segment. This helper returns true either if both pages are not zone device pages or both pages are zone device pages with the same pgmap. Factor out the check for page mergability into a pages_are_mergable() helper and add a check with zone_device_pages_are_mergeable(). Signed-off-by: Logan Gunthorpe Reviewed-by: Christoph Hellwig Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20221021174116.7200-6-logang@deltatee.com Signed-off-by: Jens Axboe