--- /dev/null
+From nathan@kernel.org Wed Jun 7 20:32:10 2023
+From: Nathan Chancellor <nathan@kernel.org>
+Date: Mon, 05 Jun 2023 14:15:08 -0700
+Subject: riscv: vmlinux.lds.S: Explicitly handle '.got' section
+To: gregkh@linuxfoundation.org, sashal@kernel.org, palmer@dabbelt.com, conor@kernel.org
+Cc: paul.walmsley@sifive.com, aou@eecs.berkeley.edu, ndesaulniers@google.com, trix@redhat.com, stable@vger.kernel.org, linux-riscv@lists.infradead.org, llvm@lists.linux.dev, patches@lists.linux.dev, Nathan Chancellor <nathan@kernel.org>
+Message-ID: <20230605-6-3-riscv-got-orphan-warning-llvm-17-v1-1-72c4f11e020f@kernel.org>
+
+From: Nathan Chancellor <nathan@kernel.org>
+
+This patch is for linux-6.3.y only, it has no direct mainline
+equivalent.
+
+LLVM 17 will now use the GOT for extern weak symbols when using the
+medany model, which causes a linker orphan section warning on
+linux-6.3.y:
+
+ ld.lld: warning: <internal>:(.got) is being placed in '.got'
+
+This is not an issue in mainline because handling of the .got section
+was added by commit 39b33072941f ("riscv: Introduce CONFIG_RELOCATABLE")
+and further extended by commit 26e7aacb83df ("riscv: Allow to downgrade
+paging mode from the command line") in 6.4-rc1. Neither of these changes
+are suitable for stable, so add explicit handling of the .got section in
+a standalone change to align 6.3 and mainline, which addresses the
+warning.
+
+This is only an issue for 6.3 because commit f4b71bff8d85 ("riscv:
+select ARCH_WANT_LD_ORPHAN_WARN for !XIP_KERNEL") landed in 6.3-rc1, so
+earlier releases will not see this warning because it will not be
+enabled.
+
+Closes: https://github.com/ClangBuiltLinux/linux/issues/1865
+Link: https://github.com/llvm/llvm-project/commit/a178ba9fbd0a27057dc2fa4cb53c76caa013caac
+Signed-off-by: Nathan Chancellor <nathan@kernel.org>
+Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/riscv/kernel/vmlinux.lds.S | 2 ++
+ 1 file changed, 2 insertions(+)
+
+--- a/arch/riscv/kernel/vmlinux.lds.S
++++ b/arch/riscv/kernel/vmlinux.lds.S
+@@ -129,6 +129,8 @@ SECTIONS
+ *(.sdata*)
+ }
+
++ .got : { *(.got*) }
++
+ #ifdef CONFIG_EFI
+ .pecoff_edata_padding : { BYTE(0); . = ALIGN(PECOFF_FILE_ALIGNMENT); }
+ __pecoff_data_raw_size = ABSOLUTE(. - __pecoff_text_end);
--- /dev/null
+From 22ed903eee23a5b174e240f1cdfa9acf393a5210 Mon Sep 17 00:00:00 2001
+From: "Darrick J. Wong" <djwong@kernel.org>
+Date: Wed, 12 Apr 2023 15:49:23 +1000
+Subject: xfs: verify buffer contents when we skip log replay
+
+From: Darrick J. Wong <djwong@kernel.org>
+
+commit 22ed903eee23a5b174e240f1cdfa9acf393a5210 upstream.
+
+syzbot detected a crash during log recovery:
+
+XFS (loop0): Mounting V5 Filesystem bfdc47fc-10d8-4eed-a562-11a831b3f791
+XFS (loop0): Torn write (CRC failure) detected at log block 0x180. Truncating head block from 0x200.
+XFS (loop0): Starting recovery (logdev: internal)
+==================================================================
+BUG: KASAN: slab-out-of-bounds in xfs_btree_lookup_get_block+0x15c/0x6d0 fs/xfs/libxfs/xfs_btree.c:1813
+Read of size 8 at addr ffff88807e89f258 by task syz-executor132/5074
+
+CPU: 0 PID: 5074 Comm: syz-executor132 Not tainted 6.2.0-rc1-syzkaller #0
+Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
+Call Trace:
+ <TASK>
+ __dump_stack lib/dump_stack.c:88 [inline]
+ dump_stack_lvl+0x1b1/0x290 lib/dump_stack.c:106
+ print_address_description+0x74/0x340 mm/kasan/report.c:306
+ print_report+0x107/0x1f0 mm/kasan/report.c:417
+ kasan_report+0xcd/0x100 mm/kasan/report.c:517
+ xfs_btree_lookup_get_block+0x15c/0x6d0 fs/xfs/libxfs/xfs_btree.c:1813
+ xfs_btree_lookup+0x346/0x12c0 fs/xfs/libxfs/xfs_btree.c:1913
+ xfs_btree_simple_query_range+0xde/0x6a0 fs/xfs/libxfs/xfs_btree.c:4713
+ xfs_btree_query_range+0x2db/0x380 fs/xfs/libxfs/xfs_btree.c:4953
+ xfs_refcount_recover_cow_leftovers+0x2d1/0xa60 fs/xfs/libxfs/xfs_refcount.c:1946
+ xfs_reflink_recover_cow+0xab/0x1b0 fs/xfs/xfs_reflink.c:930
+ xlog_recover_finish+0x824/0x920 fs/xfs/xfs_log_recover.c:3493
+ xfs_log_mount_finish+0x1ec/0x3d0 fs/xfs/xfs_log.c:829
+ xfs_mountfs+0x146a/0x1ef0 fs/xfs/xfs_mount.c:933
+ xfs_fs_fill_super+0xf95/0x11f0 fs/xfs/xfs_super.c:1666
+ get_tree_bdev+0x400/0x620 fs/super.c:1282
+ vfs_get_tree+0x88/0x270 fs/super.c:1489
+ do_new_mount+0x289/0xad0 fs/namespace.c:3145
+ do_mount fs/namespace.c:3488 [inline]
+ __do_sys_mount fs/namespace.c:3697 [inline]
+ __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3674
+ do_syscall_x64 arch/x86/entry/common.c:50 [inline]
+ do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
+ entry_SYSCALL_64_after_hwframe+0x63/0xcd
+RIP: 0033:0x7f89fa3f4aca
+Code: 83 c4 08 5b 5d c3 66 2e 0f 1f 84 00 00 00 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
+RSP: 002b:00007fffd5fb5ef8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
+RAX: ffffffffffffffda RBX: 00646975756f6e2c RCX: 00007f89fa3f4aca
+RDX: 0000000020000100 RSI: 0000000020009640 RDI: 00007fffd5fb5f10
+RBP: 00007fffd5fb5f10 R08: 00007fffd5fb5f50 R09: 000000000000970d
+R10: 0000000000200800 R11: 0000000000000206 R12: 0000000000000004
+R13: 0000555556c6b2c0 R14: 0000000000200800 R15: 00007fffd5fb5f50
+ </TASK>
+
+The fuzzed image contains an AGF with an obviously garbage
+agf_refcount_level value of 32, and a dirty log with a buffer log item
+for that AGF. The ondisk AGF has a higher LSN than the recovered log
+item. xlog_recover_buf_commit_pass2 reads the buffer, compares the
+LSNs, and decides to skip replay because the ondisk buffer appears to be
+newer.
+
+Unfortunately, the ondisk buffer is corrupt, but recovery just read the
+buffer with no buffer ops specified:
+
+ error = xfs_buf_read(mp->m_ddev_targp, buf_f->blf_blkno,
+ buf_f->blf_len, buf_flags, &bp, NULL);
+
+Skipping the buffer leaves its contents in memory unverified. This sets
+us up for a kernel crash because xfs_refcount_recover_cow_leftovers
+reads the buffer (which is still around in XBF_DONE state, so no read
+verification) and creates a refcountbt cursor of height 32. This is
+impossible so we run off the end of the cursor object and crash.
+
+Fix this by invoking the verifier on all skipped buffers and aborting
+log recovery if the ondisk buffer is corrupt. It might be smarter to
+force replay the log item atop the buffer and then see if it'll pass the
+write verifier (like ext4 does) but for now let's go with the
+conservative option where we stop immediately.
+
+Link: https://syzkaller.appspot.com/bug?extid=7e9494b8b399902e994e
+Signed-off-by: Darrick J. Wong <djwong@kernel.org>
+Reviewed-by: Dave Chinner <dchinner@redhat.com>
+Signed-off-by: Dave Chinner <david@fromorbit.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ fs/xfs/xfs_buf_item_recover.c | 10 ++++++++++
+ 1 file changed, 10 insertions(+)
+
+--- a/fs/xfs/xfs_buf_item_recover.c
++++ b/fs/xfs/xfs_buf_item_recover.c
+@@ -943,6 +943,16 @@ xlog_recover_buf_commit_pass2(
+ if (lsn && lsn != -1 && XFS_LSN_CMP(lsn, current_lsn) >= 0) {
+ trace_xfs_log_recover_buf_skip(log, buf_f);
+ xlog_recover_validate_buf_type(mp, bp, buf_f, NULLCOMMITLSN);
++
++ /*
++ * We're skipping replay of this buffer log item due to the log
++ * item LSN being behind the ondisk buffer. Verify the buffer
++ * contents since we aren't going to run the write verifier.
++ */
++ if (bp->b_ops) {
++ bp->b_ops->verify_read(bp);
++ error = bp->b_error;
++ }
+ goto out_release;
+ }
+
projects / thirdparty / kernel / stable-queue.git / commitdiff
