6.9.5-rc1 review

6.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Hari Bathini <[email protected]>

commit 2ecfe59cd7de1f202e9af2516a61fbbf93d0bd4d upstream.

With PCREL addressing, there is no kernel TOC. So, it is not setup in prologue when PCREL addressing is used. But the number of instructions to skip on a tail call was not adjusted accordingly. That resulted in not so obvious failures while using tailcalls. 'tailcalls' selftest crashed the system with the below call trace:

  bpf_test_run+0xe8/0x3cc (unreliable)
  bpf_prog_test_run_skb+0x348/0x778
  __sys_bpf+0xb04/0x2b00
  sys_bpf+0x28/0x38
  system_call_exception+0x168/0x340
  system_call_vectored_common+0x15c/0x2ec

Also, as bpf programs are always module addresses and a bpf helper in general is a core kernel text address, using PC relative addressing often fails with "out of range of pcrel address" error. Switch to using kernel base for relative addressing to handle this better.

---
 arch/powerpc/net/bpf_jit_comp64.c |   30 ++++++++++++++++--------------
 1 file changed, 16 insertions(+), 14 deletions(-)

@@ -202,7 +202,8 @@ void bpf_jit_build_epilogue(u32 *image,
 	EMIT(PPC_RAW_BLR());
 }
 
-static int bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx, u64 func)
+static int
+bpf_jit_emit_func_call_hlp(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func)
 {
 	unsigned long func_addr = func ? ppc_function_entry((void *)func) : 0;
 	long reladdr;

@@ -211,19 +212,20 @@ static int bpf_jit_emit_func_call_hlp(u3
 		return -EINVAL;
 
 	if (IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) {
-		reladdr = func_addr - CTX_NIA(ctx);
+		reladdr = func_addr - local_paca->kernelbase;
 
 		if (reladdr >= (long)SZ_8G || reladdr < -(long)SZ_8G) {
-			pr_err("eBPF: address of %ps out of range of pcrel address.\n",
-				(void *)func);
+			pr_err("eBPF: address of %ps out of range of 34-bit relative address.\n",
+			       (void *)func);
 			return -ERANGE;
 		}
-		/* pla r12,addr */
-		EMIT(PPC_PREFIX_MLS | __PPC_PRFX_R(1) | IMM_H18(reladdr));
-		EMIT(PPC_INST_PADDI | ___PPC_RT(_R12) | IMM_L(reladdr));
-		EMIT(PPC_RAW_MTCTR(_R12));
-		EMIT(PPC_RAW_BCTR());
-
+		EMIT(PPC_RAW_LD(_R12, _R13, offsetof(struct paca_struct, kernelbase)));
+		/* Align for subsequent prefix instruction */
+		if (!IS_ALIGNED((unsigned long)fimage + CTX_NIA(ctx), 8))
+			EMIT(PPC_RAW_NOP());
+		/* paddi r12,r12,addr */
+		EMIT(PPC_PREFIX_MLS | __PPC_PRFX_R(0) | IMM_H18(reladdr));
+		EMIT(PPC_INST_PADDI | ___PPC_RT(_R12) | ___PPC_RA(_R12) | IMM_L(reladdr));
 	} else {
 		reladdr = func_addr - kernel_toc_addr();
 		if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) {

@@ -233,9 +235,9 @@ static int bpf_jit_emit_func_call_hlp(u3
 
 		EMIT(PPC_RAW_ADDIS(_R12, _R2, PPC_HA(reladdr)));
 		EMIT(PPC_RAW_ADDI(_R12, _R12, PPC_LO(reladdr)));
-		EMIT(PPC_RAW_MTCTR(_R12));
-		EMIT(PPC_RAW_BCTRL());
 	}
+	EMIT(PPC_RAW_MTCTR(_R12));
+	EMIT(PPC_RAW_BCTRL());
 
 	return 0;
 }

@@ -285,7 +287,7 @@ static int bpf_jit_emit_tail_call(u32 *i
 	int b2p_index = bpf_to_ppc(BPF_REG_3);
 	int bpf_tailcall_prologue_size = 8;
 
-	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2))
+	if (!IS_ENABLED(CONFIG_PPC_KERNEL_PCREL) && IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2))
 		bpf_tailcall_prologue_size += 4; /* skip past the toc load */
 
 	/*

@@ -993,7 +995,7 @@ emit_clear:
 				return ret;
 
 			if (func_addr_fixed)
-				ret = bpf_jit_emit_func_call_hlp(image, ctx, func_addr);
+				ret = bpf_jit_emit_func_call_hlp(image, fimage, ctx, func_addr);
 			else
 				ret = bpf_jit_emit_func_call_rel(image, fimage, ctx, func_addr);
 

6.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Puranjay Mohan <[email protected]>

commit b1e7cee96127468c2483cf10c2899c9b5cf79bf8 upstream.

The Linux Kernel Memory Model [1][2] requires RMW operations that have a return value to be fully ordered.

BPF atomic operations with BPF_FETCH (including BPF_XCHG and BPF_CMPXCHG) return a value back so they need to be JITed to fully ordered operations. POWERPC currently emits relaxed operations for these.

We can show this by running the following litmus-test:

PPC SB+atomic_add+fetch

  {
      0:r0=x;  (* dst reg assuming offset is 0 *)
      0:r1=2;  (* src reg *)
      0:r2=1;
      0:r4=y;  (* P0 writes to this, P1 reads this *)
      0:r5=z;  (* P1 writes to this, P0 reads this *)
      0:r6=0;

      1:r2=1;
      1:r4=y;
      1:r5=z;

}

  P0                      | P1            ;
  stw         r2, 0(r4)   | stw  r2,0(r5) ;
                          |               ;
  loop:lwarx  r3, r6, r0  |               ;
  mr          r8, r3      |               ;
  add         r3, r3, r1  | sync          ;
  stwcx.      r3, r6, r0  |               ;
  bne         loop        |               ;
  mr          r1, r8      |               ;
                          |               ;
  lwa         r7, 0(r5)   | lwa  r7,0(r4) ;

~exists(0:r7=0 /\ 1:r7=0)

Witnesses
Positive: 9 Negative: 3
Condition ~exists (0:r7=0 /\ 1:r7=0)
Observation SB+atomic_add+fetch Sometimes 3 9

This test shows that the older store in P0 is reordered with a newer load to a different address. Although there is a RMW operation with fetch between them. Adding a sync before and after RMW fixes the issue:

Witnesses
Positive: 9 Negative: 0
Condition ~exists (0:r7=0 /\ 1:r7=0)
Observation SB+atomic_add+fetch Never 0 9

[1] https://www.kernel.org/doc/Documentation/memory-barriers.txt
[2] https://www.kernel.org/doc/Documentation/atomic_t.txt

---
 arch/powerpc/net/bpf_jit_comp32.c |   12 ++++++++++++
 arch/powerpc/net/bpf_jit_comp64.c |   12 ++++++++++++
 2 files changed, 24 insertions(+)

@@ -900,6 +900,15 @@ int bpf_jit_build_body(struct bpf_prog *
 
 			/* Get offset into TMP_REG */
 			EMIT(PPC_RAW_LI(tmp_reg, off));
+			/*
+			 * Enforce full ordering for operations with BPF_FETCH by emitting a 'sync'
+			 * before and after the operation.
+			 *
+			 * This is a requirement in the Linux Kernel Memory Model.
+			 * See __cmpxchg_u32() in asm/cmpxchg.h as an example.
+			 */
+			if ((imm & BPF_FETCH) && IS_ENABLED(CONFIG_SMP))
+				EMIT(PPC_RAW_SYNC());
 			tmp_idx = ctx->idx * 4;
 			/* load value from memory into r0 */
 			EMIT(PPC_RAW_LWARX(_R0, tmp_reg, dst_reg, 0));

@@ -953,6 +962,9 @@ int bpf_jit_build_body(struct bpf_prog *
 
 			/* For the BPF_FETCH variant, get old data into src_reg */
 			if (imm & BPF_FETCH) {
+				/* Emit 'sync' to enforce full ordering */
+				if (IS_ENABLED(CONFIG_SMP))
+					EMIT(PPC_RAW_SYNC());
 				EMIT(PPC_RAW_MR(ret_reg, ax_reg));
 				if (!fp->aux->verifier_zext)
 					EMIT(PPC_RAW_LI(ret_reg - 1, 0)); /* higher 32-bit */

@@ -805,6 +805,15 @@ emit_clear:
 
 			/* Get offset into TMP_REG_1 */
 			EMIT(PPC_RAW_LI(tmp1_reg, off));
+			/*
+			 * Enforce full ordering for operations with BPF_FETCH by emitting a 'sync'
+			 * before and after the operation.
+			 *
+			 * This is a requirement in the Linux Kernel Memory Model.
+			 * See __cmpxchg_u64() in asm/cmpxchg.h as an example.
+			 */
+			if ((imm & BPF_FETCH) && IS_ENABLED(CONFIG_SMP))
+				EMIT(PPC_RAW_SYNC());
 			tmp_idx = ctx->idx * 4;
 			/* load value from memory into TMP_REG_2 */
 			if (size == BPF_DW)

@@ -867,6 +876,9 @@ emit_clear:
 			PPC_BCC_SHORT(COND_NE, tmp_idx);
 
 			if (imm & BPF_FETCH) {
+				/* Emit 'sync' to enforce full ordering */
+				if (IS_ENABLED(CONFIG_SMP))
+					EMIT(PPC_RAW_SYNC());
 				EMIT(PPC_RAW_MR(ret_reg, _R0));
 				/*
 				 * Skip unnecessary zero-extension for 32-bit cmpxchg.

6.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Ryusuke Konishi <[email protected]>

commit a4ca369ca221bb7e06c725792ac107f0e48e82e7 upstream.

Destructive writes to a block device on which nilfs2 is mounted can cause a kernel bug in the folio/page writeback start routine or writeback end routine (__folio_start_writeback in the log below):

kernel BUG at mm/page-writeback.c:3070!

 Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
 ...
 RIP: 0010:__folio_start_writeback+0xbaa/0x10e0
 Code: 25 ff 0f 00 00 0f 84 18 01 00 00 e8 40 ca c6 ff e9 17 f6 ff ff
  e8 36 ca c6 ff 4c 89 f7 48 c7 c6 80 c0 12 84 e8 e7 b3 0f 00 90 <0f>
  0b e8 1f ca c6 ff 4c 89 f7 48 c7 c6 a0 c6 12 84 e8 d0 b3 0f 00
 ...
 Call Trace:
  <TASK>
  nilfs_segctor_do_construct+0x4654/0x69d0 [nilfs2]
  nilfs_segctor_construct+0x181/0x6b0 [nilfs2]
  nilfs_segctor_thread+0x548/0x11c0 [nilfs2]
  kthread+0x2f0/0x390
  ret_from_fork+0x4b/0x80
  ret_from_fork_asm+0x1a/0x30
  </TASK>

This is because when the log writer starts a writeback for segment summary blocks or a super root block that use the backing device's page cache, it does not wait for the ongoing folio/page writeback, resulting in an inconsistent writeback state.

Fix this issue by waiting for ongoing writebacks when putting folios/pages on the backing device into writeback state.

---
 fs/nilfs2/segment.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -1652,6 +1652,7 @@ static void nilfs_segctor_prepare_write(
 			if (bh->b_folio != bd_folio) {
 				if (bd_folio) {
 					folio_lock(bd_folio);
+					folio_wait_writeback(bd_folio);
 					folio_clear_dirty_for_io(bd_folio);
 					folio_start_writeback(bd_folio);
 					folio_unlock(bd_folio);

@@ -1665,6 +1666,7 @@ static void nilfs_segctor_prepare_write(
 			if (bh == segbuf->sb_super_root) {
 				if (bh->b_folio != bd_folio) {
 					folio_lock(bd_folio);
+					folio_wait_writeback(bd_folio);
 					folio_clear_dirty_for_io(bd_folio);
 					folio_start_writeback(bd_folio);
 					folio_unlock(bd_folio);

@@ -1681,6 +1683,7 @@ static void nilfs_segctor_prepare_write(
 	}
 	if (bd_folio) {
 		folio_lock(bd_folio);
+		folio_wait_writeback(bd_folio);
 		folio_clear_dirty_for_io(bd_folio);
 		folio_start_writeback(bd_folio);
 		folio_unlock(bd_folio);

6.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Ryusuke Konishi <[email protected]>

commit 7373a51e7998b508af7136530f3a997b286ce81c upstream.

The error handling in nilfs_empty_dir() when a directory folio/page read fails is incorrect, as in the old ext2 implementation, and if the folio/page cannot be read or nilfs_check_folio() fails, it will falsely determine the directory as empty and corrupt the file system.

In addition, since nilfs_empty_dir() does not immediately return on a failed folio/page read, but continues to loop, this can cause a long loop with I/O if i_size of the directory's inode is also corrupted, causing the log writer thread to wait and hang, as reported by syzbot.

Fix these issues by making nilfs_empty_dir() immediately return a false value (0) if it fails to get a directory folio/page.

---
 fs/nilfs2/dir.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -608,7 +608,7 @@ int nilfs_empty_dir(struct inode *inode)
 
 		kaddr = nilfs_get_folio(inode, i, &folio);
 		if (IS_ERR(kaddr))
-			continue;
+			return 0;
 
 		de = (struct nilfs_dir_entry *)kaddr;
 		kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1);

6.9-stable review patch. If anyone has any objections, please let me know.

------------------

From: Enzo Matsumiya <[email protected]>

commit 02c418774f76a0a36a6195c9dbf8971eb4130a15 upstream.

Unlock cifs_tcp_ses_lock before calling cifs_put_smb_ses() to avoid such deadlock.

---
 fs/smb/client/smb2transport.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -216,8 +216,8 @@ smb2_find_smb_tcon(struct TCP_Server_Inf
 	}
 	tcon = smb2_find_smb_sess_tcon_unlocked(ses, tid);
 	if (!tcon) {
-		cifs_put_smb_ses(ses);
 		spin_unlock(&cifs_tcp_ses_lock);
+		cifs_put_smb_ses(ses);
 		return NULL;
 	}
 	spin_unlock(&cifs_tcp_ses_lock);

Hello,

This rc kernel passes DAMON functionality test[1] on my test machine. Attaching the test results summary below. Please note that I retrieved the kernel from linux-stable-rc tree[2].

[1] https://github.com/awslabs/damon-tests/tree/next/corr
[2] 35fcf9de8f9d ("Linux 6.9.5-rc1")

Thanks,
SJ

[...]

---

ok 6 selftests: damon: debugfs_duplicate_context_creation.sh
ok 7 selftests: damon: debugfs_rm_non_contexts.sh
ok 8 selftests: damon: debugfs_target_ids_read_before_terminate_race.sh ok 9 selftests: damon: debugfs_target_ids_pid_leak.sh
ok 10 selftests: damon: sysfs.sh
ok 11 selftests: damon: sysfs_update_removed_scheme_dir.sh
ok 12 selftests: damon: sysfs_update_schemes_tried_regions_hang.py ok 13 selftests: damon: sysfs_update_schemes_tried_regions_wss_estimation.py ok 14 selftests: damon: damos_quota.py
ok 15 selftests: damon: damos_apply_interval.py
ok 16 selftests: damon: reclaim.sh
ok 17 selftests: damon: lru_sort.sh
ok 1 selftests: damon-tests: kunit.sh
ok 2 selftests: damon-tests: huge_count_read_write.sh
ok 3 selftests: damon-tests: buffer_overflow.sh
ok 4 selftests: damon-tests: rm_contexts.sh
ok 5 selftests: damon-tests: record_null_deref.sh
ok 6 selftests: damon-tests: dbgfs_target_ids_read_before_terminate_race.sh ok 7 selftests: damon-tests: dbgfs_target_ids_pid_leak.sh
ok 8 selftests: damon-tests: damo_tests.sh
ok 9 selftests: damon-tests: masim-record.sh
ok 10 selftests: damon-tests: build_i386.sh
ok 11 selftests: damon-tests: build_arm64.sh
ok 12 selftests: damon-tests: build_m68k.sh
ok 13 selftests: damon-tests: build_i386_idle_flag.sh
ok 14 selftests: damon-tests: build_i386_highpte.sh
ok 15 selftests: damon-tests: build_nomemcg.sh
[33m
[92mPASS [39m

Successfully compiled and installed the kernel on my computer (Acer Aspire E15, Intel Core i3 Haswell). No noticeable regressions.

An old man doll... just what I always wanted! - Clara

Results from Linaro’s test farm.
No regressions on arm64, arm, x86_64, and i386.

## Build
* kernel: 6.9.5-rc1
* git: https://gitlab.com/Linaro/lkft/mirrors/stable/linux-stable-rc
* git branch: linux-6.9.y
* git commit: 3fc8ec8cbfb63bed37f4702410201c973a690450
* git describe: v6.9.2-957-g3fc8ec8cbfb6
* test details:
https://qa-reports.linaro.org/lkft/linux-stable-rc-linux-6.9.y/build/v6.9.2-957-g3fc8ec8cbfb6

## Test Regressions (compared to v6.9.2-797-g4aee3af1daf2)

## Metric Regressions (compared to v6.9.2-797-g4aee3af1daf2)

## Test Fixes (compared to v6.9.2-797-g4aee3af1daf2)

## Metric Fixes (compared to v6.9.2-797-g4aee3af1daf2)

## Test result summary
total: 163101, pass: 141914, fail: 2059, skip: 19128, xfail: 0

## Build Summary
* arc: 5 total, 5 passed, 0 failed
* arm: 129 total, 129 passed, 0 failed
* arm64: 38 total, 38 passed, 0 failed
* i386: 29 total, 29 passed, 0 failed
* mips: 24 total, 24 passed, 0 failed
* parisc: 3 total, 3 passed, 0 failed
* powerpc: 34 total, 34 passed, 0 failed
* riscv: 17 total, 17 passed, 0 failed
* s390: 12 total, 12 passed, 0 failed
* sh: 10 total, 10 passed, 0 failed
* sparc: 6 total, 6 passed, 0 failed
* x86_64: 33 total, 33 passed, 0 failed

## Test suites summary
* boot
* kselftest-android
* kselftest-arm64
* kselftest-breakpoints
* kselftest-capabilities
* kselftest-cgroup
* kselftest-clone3
* kselftest-core
* kselftest-cpu-hotplug
* kselftest-cpufreq
* kselftest-drivers-dma-buf
* kselftest-efivarfs
* kselftest-exec
* kselftest-filesystems
* kselftest-filesystems-binderfs
* kselftest-filesystems-epoll
* kselftest-firmware
* kselftest-fpu
* kselftest-ftrace
* kselftest-futex
* kselftest-gpio
* kselftest-intel_pstate
* kselftest-ipc
* kselftest-ir
* kselftest-kcmp
* kselftest-kexec
* kselftest-kvm
* kselftest-lib
* kselftest-livepatch
* kselftest-membarrier
* kselftest-memfd
* kselftest-memory-hotplug
* kselftest-mincore
* kselftest-mm
* kselftest-mount
* kselftest-mqueue
* kselftest-net
* kselftest-net-forwarding
* kselftest-net-mptcp
* kselftest-netfilter
* kselftest-nsfs
* kselftest-openat2
* kselftest-pid_namespace
* kselftest-pidfd
* kselftest-proc
* kselftest-pstore
* kselftest-ptrace
* kselftest-rseq
* kselftest-rtc
* kselftest-seccomp
* kselftest-sigaltstack
* kselftest-size
* kselftest-splice
* kselftest-static_keys
* kselftest-sync
* kselftest-sysctl
* kselftest-tc-testing
* kselftest-timens
* kselftest-timers
* kselftest-tmpfs
* kselftest-tpm2
* kselftest-user
* kselftest-user_events
* kselftest-vDSO
* kselftest-watchdog
* kselftest-x86
* kselftest-zram
* kunit
* kvm-unit-tests
* libgpiod
* libhugetlbfs
* log-parser-boot
* log-parser-test
* ltp-commands
* ltp-containers
* ltp-controllers
* ltp-cpuhotplug
* ltp-crypto
* ltp-cve
* ltp-dio
* ltp-fcntl-locktests
* ltp-fs
* ltp-fs_bind
* ltp-fs_perms_simple
* ltp-hugetlb
* ltp-ipc
* ltp-math
* ltp-mm
* ltp-nptl
* ltp-pty
* ltp-sched
* ltp-smoke
* ltp-smoketest
* ltp-syscalls
* ltp-tracing
* perf
* rcutorture

--
Linaro LKFT
https://lkft.linaro.org

Hi!

CIP testing did not find any problems here:

https://gitlab.com/cip-project/cip-testing/linux-stable-rc-ci/-/tree/linux-6.9.y

6.6, 5.15, 5.4 pass our testing, too:

https://gitlab.com/cip-project/cip-testing/linux-stable-rc-ci/-/tree/linux-6.6.y
https://gitlab.com/cip-project/cip-testing/linux-stable-rc-ci/-/tree/linux-5.15.y
https://gitlab.com/cip-project/cip-testing/linux-stable-rc-ci/-/tree/linux-5.4.y

Best regards,
Pavel

DENX Software Engineering GmbH,        Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

Built and booted successfully on RISC-V RV64 (HiFive Unmatched).

All tests passing for Tegra ...

Test results for stable-v6.9:

    10 builds:	10 pass, 0 fail
    26 boots:	26 pass, 0 fail
    116 tests:	116 pass, 0 fail

Linux version: 6.9.5-rc1-g3fc8ec8cbfb6
Boards tested: tegra124-jetson-tk1, tegra186-p2771-0000,

                tegra194-p2972-0000, tegra194-p3509-0000+p3668-0000,
                tegra20-ventana, tegra210-p2371-2180,
                tegra210-p3450-0000, tegra30-cardhu-a04

Jon

Am 13.06.2024 um 13:32 schrieb Greg Kroah-Hartman:

Builds, boots and works fine w/o regressions on 2-socket Ivy Bridge Xeon E5-2697 v2. Everything looking good. Except from simply firing up 12 VMs, I have not done any serious load testing this time though.

Beste Grüße,
Peter Schneider

Climb the mountain not to plant your flag, but to embrace the challenge,
enjoy the air and behold the view. Climb it so you can see the world,
not so the world can see you.                    -- David McCullough Jr.

OpenPGP:  0xA3828BD796CCE11A8CADE8866E3A92C92C3FF244
Download: https://www.peters-netzplatz.de/download/pschneider1968_pub.asc
https://keys.mailvelope.com/pks/lookup?op=get&[email protected]
https://keys.mailvelope.com/pks/lookup?op=get&[email protected]

Compiled and booted on my test system. No dmesg regressions.

thanks,
-- Shuah

On ARCH_BRCMST using 32-bit and 64-bit ARM kernels, build tested on BMIPS_GENERIC:

Florian