December 2023 - Linux-stable-mirror

stable-rc/queue/5.10 build: 18 builds: 0 failed, 18 passed, 5 warnings (v5.10.204-33-g1ff0e69a5e9be)

by kernelci.org bot

stable-rc/queue/5.10 build: 18 builds: 0 failed, 18 passed, 5 warnings (v5.10.204-33-g1ff0e69a5e9be) Full Build Summary: https://kernelci.org/build/stable-rc/branch/queue%2F5.10/kernel/v5.10.204-3… Tree: stable-rc Branch: queue/5.10 Git Describe: v5.10.204-33-g1ff0e69a5e9be Git Commit: 1ff0e69a5e9bee56f32bbbbec8c916c63579f7a6 Git URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git Built: 7 unique architectures Warnings Detected: arc: arm64: arm: i386: mips: 32r2el_defconfig (gcc-10): 1 warning riscv: rv32_defconfig (gcc-10): 4 warnings x86_64: Warnings summary: 2 <stdin>:830:2: warning: #warning syscall fstat64 not implemented [-Wcpp] 2 <stdin>:1127:2: warning: #warning syscall fstatat64 not implemented [-Wcpp] 1 WARNING: modpost: Symbol info of vmlinux is missing. Unresolved symbol check will be entirely skipped. ================================================================================ Detailed per-defconfig build reports: -------------------------------------------------------------------------------- 32r2el_defconfig (mips, gcc-10) — PASS, 0 errors, 1 warning, 0 section mismatches Warnings: WARNING: modpost: Symbol info of vmlinux is missing. Unresolved symbol check will be entirely skipped. -------------------------------------------------------------------------------- allnoconfig (i386, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- allnoconfig (x86_64, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- defconfig (riscv, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- defconfig (arm64, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- defconfig+arm64-chromebook (arm64, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- haps_hs_smp_defconfig (arc, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- i386_defconfig (i386, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- imx_v6_v7_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- multi_v5_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- multi_v7_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- nommu_k210_defconfig (riscv, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- omap2plus_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- rv32_defconfig (riscv, gcc-10) — PASS, 0 errors, 4 warnings, 0 section mismatches Warnings: <stdin>:830:2: warning: #warning syscall fstat64 not implemented [-Wcpp] <stdin>:1127:2: warning: #warning syscall fstatat64 not implemented [-Wcpp] <stdin>:830:2: warning: #warning syscall fstat64 not implemented [-Wcpp] <stdin>:1127:2: warning: #warning syscall fstatat64 not implemented [-Wcpp] -------------------------------------------------------------------------------- tinyconfig (x86_64, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- tinyconfig (i386, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- vexpress_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- x86_64_defconfig (x86_64, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- x86_64_defconfig+x86-board (x86_64, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches --- For more info write to <info(a)kernelci.org>

1 year, 5 months

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stable-rc/queue/5.4 build: 17 builds: 0 failed, 17 passed, 26 warnings (v5.4.264-16-g0c79506e81298)

by kernelci.org bot

stable-rc/queue/5.4 build: 17 builds: 0 failed, 17 passed, 26 warnings (v5.4.264-16-g0c79506e81298) Full Build Summary: https://kernelci.org/build/stable-rc/branch/queue%2F5.4/kernel/v5.4.264-16-… Tree: stable-rc Branch: queue/5.4 Git Describe: v5.4.264-16-g0c79506e81298 Git Commit: 0c79506e81298e7635e4a51c281e673db3ce7e08 Git URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git Built: 7 unique architectures Warnings Detected: arc: arm64: defconfig (gcc-10): 2 warnings defconfig+arm64-chromebook (gcc-10): 2 warnings arm: i386: allnoconfig (gcc-10): 2 warnings i386_defconfig (gcc-10): 2 warnings tinyconfig (gcc-10): 2 warnings mips: riscv: x86_64: allnoconfig (gcc-10): 4 warnings tinyconfig (gcc-10): 4 warnings x86_64_defconfig (gcc-10): 4 warnings x86_64_defconfig+x86-board (gcc-10): 4 warnings Warnings summary: 7 ld: warning: creating DT_TEXTREL in a PIE 4 ld: arch/x86/boot/compressed/head_64.o: warning: relocation in read-only section `.head.text' 4 arch/arm64/include/asm/memory.h:238:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] 3 ld: arch/x86/boot/compressed/head_32.o: warning: relocation in read-only section `.head.text' 2 arch/x86/entry/entry_64.o: warning: objtool: If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE. 2 arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x1c1: unsupported intra-function call 2 arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x151: unsupported intra-function call 2 arch/x86/entry/entry_64.S:1756: Warning: no instruction mnemonic suffix given and no register operands; using default for `sysret' Section mismatches summary: 1 WARNING: vmlinux.o(___ksymtab_gpl+vic_init_cascaded+0x0): Section mismatch in reference from the variable __ksymtab_vic_init_cascaded to the function .init.text:vic_init_cascaded() ================================================================================ Detailed per-defconfig build reports: -------------------------------------------------------------------------------- 32r2el_defconfig (mips, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- allnoconfig (x86_64, gcc-10) — PASS, 0 errors, 4 warnings, 0 section mismatches Warnings: arch/x86/entry/entry_64.S:1756: Warning: no instruction mnemonic suffix given and no register operands; using default for `sysret' arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x151: unsupported intra-function call ld: arch/x86/boot/compressed/head_64.o: warning: relocation in read-only section `.head.text' ld: warning: creating DT_TEXTREL in a PIE -------------------------------------------------------------------------------- allnoconfig (i386, gcc-10) — PASS, 0 errors, 2 warnings, 0 section mismatches Warnings: ld: arch/x86/boot/compressed/head_32.o: warning: relocation in read-only section `.head.text' ld: warning: creating DT_TEXTREL in a PIE -------------------------------------------------------------------------------- defconfig (riscv, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- defconfig (arm64, gcc-10) — PASS, 0 errors, 2 warnings, 0 section mismatches Warnings: arch/arm64/include/asm/memory.h:238:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] arch/arm64/include/asm/memory.h:238:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] -------------------------------------------------------------------------------- defconfig+arm64-chromebook (arm64, gcc-10) — PASS, 0 errors, 2 warnings, 0 section mismatches Warnings: arch/arm64/include/asm/memory.h:238:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] arch/arm64/include/asm/memory.h:238:15: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] -------------------------------------------------------------------------------- haps_hs_smp_defconfig (arc, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- i386_defconfig (i386, gcc-10) — PASS, 0 errors, 2 warnings, 0 section mismatches Warnings: ld: arch/x86/boot/compressed/head_32.o: warning: relocation in read-only section `.head.text' ld: warning: creating DT_TEXTREL in a PIE -------------------------------------------------------------------------------- imx_v6_v7_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- multi_v5_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches Section mismatches: WARNING: vmlinux.o(___ksymtab_gpl+vic_init_cascaded+0x0): Section mismatch in reference from the variable __ksymtab_vic_init_cascaded to the function .init.text:vic_init_cascaded() -------------------------------------------------------------------------------- multi_v7_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- omap2plus_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- tinyconfig (i386, gcc-10) — PASS, 0 errors, 2 warnings, 0 section mismatches Warnings: ld: arch/x86/boot/compressed/head_32.o: warning: relocation in read-only section `.head.text' ld: warning: creating DT_TEXTREL in a PIE -------------------------------------------------------------------------------- tinyconfig (x86_64, gcc-10) — PASS, 0 errors, 4 warnings, 0 section mismatches Warnings: arch/x86/entry/entry_64.S:1756: Warning: no instruction mnemonic suffix given and no register operands; using default for `sysret' arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x151: unsupported intra-function call ld: arch/x86/boot/compressed/head_64.o: warning: relocation in read-only section `.head.text' ld: warning: creating DT_TEXTREL in a PIE -------------------------------------------------------------------------------- vexpress_defconfig (arm, gcc-10) — PASS, 0 errors, 0 warnings, 0 section mismatches -------------------------------------------------------------------------------- x86_64_defconfig (x86_64, gcc-10) — PASS, 0 errors, 4 warnings, 0 section mismatches Warnings: arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x1c1: unsupported intra-function call arch/x86/entry/entry_64.o: warning: objtool: If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE. ld: arch/x86/boot/compressed/head_64.o: warning: relocation in read-only section `.head.text' ld: warning: creating DT_TEXTREL in a PIE -------------------------------------------------------------------------------- x86_64_defconfig+x86-board (x86_64, gcc-10) — PASS, 0 errors, 4 warnings, 0 section mismatches Warnings: arch/x86/entry/entry_64.o: warning: objtool: .entry.text+0x1c1: unsupported intra-function call arch/x86/entry/entry_64.o: warning: objtool: If this is a retpoline, please patch it in with alternatives and annotate it with ANNOTATE_NOSPEC_ALTERNATIVE. ld: arch/x86/boot/compressed/head_64.o: warning: relocation in read-only section `.head.text' ld: warning: creating DT_TEXTREL in a PIE --- For more info write to <info(a)kernelci.org>

1 year, 5 months

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[PATCH v5 1/2] bus: mhi: host: Add spinlock to protect WP access when queueing TREs

by Qiang Yu

From: Bhaumik Bhatt <bbhatt(a)codeaurora.org> Protect WP accesses such that multiple threads queueing buffers for incoming data do not race. Meanwhile, if CONFIG_TRACE_IRQFLAGS is enabled, irq will be enabled once __local_bh_enable_ip is called as part of write_unlock_bh. Hence, let's take irqsave lock after TRE is generated to avoid running write_unlock_bh when irqsave lock is held. Cc: <stable(a)vger.kernel.org> Fixes: 189ff97cca53 ("bus: mhi: core: Add support for data transfer") Signed-off-by: Bhaumik Bhatt <bbhatt(a)codeaurora.org> Signed-off-by: Qiang Yu <quic_qianyu(a)quicinc.com> --- drivers/bus/mhi/host/main.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) diff --git a/drivers/bus/mhi/host/main.c b/drivers/bus/mhi/host/main.c index dcf627b..32021fe 100644 --- a/drivers/bus/mhi/host/main.c +++ b/drivers/bus/mhi/host/main.c @@ -1122,17 +1122,15 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info, if (unlikely(MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))) return -EIO; - read_lock_irqsave(&mhi_cntrl->pm_lock, flags); - ret = mhi_is_ring_full(mhi_cntrl, tre_ring); - if (unlikely(ret)) { - ret = -EAGAIN; - goto exit_unlock; - } + if (unlikely(ret)) + return -EAGAIN; ret = mhi_gen_tre(mhi_cntrl, mhi_chan, buf_info, mflags); if (unlikely(ret)) - goto exit_unlock; + return ret; + + read_lock_irqsave(&mhi_cntrl->pm_lock, flags); /* Packet is queued, take a usage ref to exit M3 if necessary * for host->device buffer, balanced put is done on buffer completion @@ -1152,7 +1150,6 @@ static int mhi_queue(struct mhi_device *mhi_dev, struct mhi_buf_info *buf_info, if (dir == DMA_FROM_DEVICE) mhi_cntrl->runtime_put(mhi_cntrl); -exit_unlock: read_unlock_irqrestore(&mhi_cntrl->pm_lock, flags); return ret; @@ -1204,6 +1201,9 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan, int eot, eob, chain, bei; int ret; + /* Protect accesses for reading and incrementing WP */ + write_lock_bh(&mhi_chan->lock); + buf_ring = &mhi_chan->buf_ring; tre_ring = &mhi_chan->tre_ring; @@ -1221,8 +1221,10 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan, if (!info->pre_mapped) { ret = mhi_cntrl->map_single(mhi_cntrl, buf_info); - if (ret) + if (ret) { + write_unlock_bh(&mhi_chan->lock); return ret; + } } eob = !!(flags & MHI_EOB); @@ -1239,6 +1241,8 @@ int mhi_gen_tre(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan, mhi_add_ring_element(mhi_cntrl, tre_ring); mhi_add_ring_element(mhi_cntrl, buf_ring); + write_unlock_bh(&mhi_chan->lock); + return 0; } -- 2.7.4

1 year, 5 months

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[for-linus][PATCH 14/15] ring-buffer: Have rb_time_cmpxchg() set the msb counter too

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> The rb_time_cmpxchg() on 32-bit architectures requires setting three 32-bit words to represent the 64-bit timestamp, with some salt for synchronization. Those are: msb, top, and bottom The issue is, the rb_time_cmpxchg() did not properly salt the msb portion, and the msb that was written was stale. Link: https://lore.kernel.org/linux-trace-kernel/20231215084114.20899342@rorschac… Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Fixes: f03f2abce4f39 ("ring-buffer: Have 32 bit time stamps use all 64 bits") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/ring_buffer.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index f22a849da179..f4679013289b 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -722,10 +722,12 @@ static bool rb_time_cmpxchg(rb_time_t *t, u64 expect, u64 set) cnt2 = cnt + 1; rb_time_split(val, &top, &bottom, &msb); + msb = rb_time_val_cnt(msb, cnt); top = rb_time_val_cnt(top, cnt); bottom = rb_time_val_cnt(bottom, cnt); rb_time_split(set, &top2, &bottom2, &msb2); + msb2 = rb_time_val_cnt(msb2, cnt); top2 = rb_time_val_cnt(top2, cnt2); bottom2 = rb_time_val_cnt(bottom2, cnt2); -- 2.42.0

1 year, 5 months

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[for-linus][PATCH 12/15] ring-buffer: Fix a race in rb_time_cmpxchg() for 32 bit archs

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Mathieu Desnoyers pointed out an issue in the rb_time_cmpxchg() for 32 bit architectures. That is: static bool rb_time_cmpxchg(rb_time_t *t, u64 expect, u64 set) { unsigned long cnt, top, bottom, msb; unsigned long cnt2, top2, bottom2, msb2; u64 val; /* The cmpxchg always fails if it interrupted an update */ if (!__rb_time_read(t, &val, &cnt2)) return false; if (val != expect) return false; <<<< interrupted here! cnt = local_read(&t->cnt); The problem is that the synchronization counter in the rb_time_t is read *after* the value of the timestamp is read. That means if an interrupt were to come in between the value being read and the counter being read, it can change the value and the counter and the interrupted process would be clueless about it! The counter needs to be read first and then the value. That way it is easy to tell if the value is stale or not. If the counter hasn't been updated, then the value is still good. Link: https://lore.kernel.org/linux-trace-kernel/20231211201324.652870-1-mathieu.… Link: https://lore.kernel.org/linux-trace-kernel/20231212115301.7a9c9a64@gandalf.… Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Fixes: 10464b4aa605e ("ring-buffer: Add rb_time_t 64 bit operations for speeding up 32 bit") Reported-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/ring_buffer.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index ad4af0cba159..b8ab0557bd1b 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -706,6 +706,9 @@ static bool rb_time_cmpxchg(rb_time_t *t, u64 expect, u64 set) unsigned long cnt2, top2, bottom2, msb2; u64 val; + /* Any interruptions in this function should cause a failure */ + cnt = local_read(&t->cnt); + /* The cmpxchg always fails if it interrupted an update */ if (!__rb_time_read(t, &val, &cnt2)) return false; @@ -713,7 +716,6 @@ static bool rb_time_cmpxchg(rb_time_t *t, u64 expect, u64 set) if (val != expect) return false; - cnt = local_read(&t->cnt); if ((cnt & 3) != cnt2) return false; -- 2.42.0

1 year, 5 months

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[for-linus][PATCH 10/15] ring-buffer: Do not try to put back write_stamp

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> If an update to an event is interrupted by another event between the time the initial event allocated its buffer and where it wrote to the write_stamp, the code try to reset the write stamp back to the what it had just overwritten. It knows that it was overwritten via checking the before_stamp, and if it didn't match what it wrote to the before_stamp before it allocated its space, it knows it was overwritten. To put back the write_stamp, it uses the before_stamp it read. The problem here is that by writing the before_stamp to the write_stamp it makes the two equal again, which means that the write_stamp can be considered valid as the last timestamp written to the ring buffer. But this is not necessarily true. The event that interrupted the event could have been interrupted in a way that it was interrupted as well, and can end up leaving with an invalid write_stamp. But if this happens and returns to this context that uses the before_stamp to update the write_stamp again, it can possibly incorrectly make it valid, causing later events to have in correct time stamps. As it is OK to leave this function with an invalid write_stamp (one that doesn't match the before_stamp), there's no reason to try to make it valid again in this case. If this race happens, then just leave with the invalid write_stamp and the next event to come along will just add a absolute timestamp and validate everything again. Bonus points: This gets rid of another cmpxchg64! Link: https://lore.kernel.org/linux-trace-kernel/20231214222921.193037a7@gandalf.… Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Cc: Joel Fernandes <joel(a)joelfernandes.org> Cc: Vincent Donnefort <vdonnefort(a)google.com> Fixes: a389d86f7fd09 ("ring-buffer: Have nested events still record running time stamp") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/ring_buffer.c | 29 ++++++----------------------- 1 file changed, 6 insertions(+), 23 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 1d9caee7f542..2668dde23343 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3612,14 +3612,14 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, } if (likely(tail == w)) { - u64 save_before; - bool s_ok; - /* Nothing interrupted us between A and C */ /*D*/ rb_time_set(&cpu_buffer->write_stamp, info->ts); - barrier(); - /*E*/ s_ok = rb_time_read(&cpu_buffer->before_stamp, &save_before); - RB_WARN_ON(cpu_buffer, !s_ok); + /* + * If something came in between C and D, the write stamp + * may now not be in sync. But that's fine as the before_stamp + * will be different and then next event will just be forced + * to use an absolute timestamp. + */ if (likely(!(info->add_timestamp & (RB_ADD_STAMP_FORCE | RB_ADD_STAMP_ABSOLUTE)))) /* This did not interrupt any time update */ @@ -3627,24 +3627,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, else /* Just use full timestamp for interrupting event */ info->delta = info->ts; - barrier(); check_buffer(cpu_buffer, info, tail); - if (unlikely(info->ts != save_before)) { - /* SLOW PATH - Interrupted between C and E */ - - a_ok = rb_time_read(&cpu_buffer->write_stamp, &info->after); - RB_WARN_ON(cpu_buffer, !a_ok); - - /* Write stamp must only go forward */ - if (save_before > info->after) { - /* - * We do not care about the result, only that - * it gets updated atomically. - */ - (void)rb_time_cmpxchg(&cpu_buffer->write_stamp, - info->after, save_before); - } - } } else { u64 ts; /* SLOW PATH - Interrupted between A and C */ -- 2.42.0

1 year, 5 months

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[for-linus][PATCH 07/15] ring-buffer: Have saved event hold the entire event

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> For the ring buffer iterator (non-consuming read), the event needs to be copied into the iterator buffer to make sure that a writer does not overwrite it while the user is reading it. If a write happens during the copy, the buffer is simply discarded. But the temp buffer itself was not big enough. The allocation of the buffer was only BUF_MAX_DATA_SIZE, which is the maximum data size that can be passed into the ring buffer and saved. But the temp buffer needs to hold the meta data as well. That would be BUF_PAGE_SIZE and not BUF_MAX_DATA_SIZE. Link: https://lore.kernel.org/linux-trace-kernel/20231212072558.61f76493@gandalf.… Cc: stable(a)vger.kernel.org Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Fixes: 785888c544e04 ("ring-buffer: Have rb_iter_head_event() handle concurrent writer") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/ring_buffer.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index c7abcc215fe2..1d9caee7f542 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2409,7 +2409,7 @@ rb_iter_head_event(struct ring_buffer_iter *iter) */ barrier(); - if ((iter->head + length) > commit || length > BUF_MAX_DATA_SIZE) + if ((iter->head + length) > commit || length > BUF_PAGE_SIZE) /* Writer corrupted the read? */ goto reset; @@ -5118,7 +5118,8 @@ ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags) if (!iter) return NULL; - iter->event = kmalloc(BUF_MAX_DATA_SIZE, flags); + /* Holds the entire event: data and meta data */ + iter->event = kmalloc(BUF_PAGE_SIZE, flags); if (!iter->event) { kfree(iter); return NULL; -- 2.42.0

1 year, 5 months

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[for-linus][PATCH 06/15] ring-buffer: Do not update before stamp when switching sub-buffers

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> The ring buffer timestamps are synchronized by two timestamp placeholders. One is the "before_stamp" and the other is the "write_stamp" (sometimes referred to as the "after stamp" but only in the comments. These two stamps are key to knowing how to handle nested events coming in with a lockless system. When moving across sub-buffers, the before stamp is updated but the write stamp is not. There's an effort to put back the before stamp to something that seems logical in case there's nested events. But as the current event is about to cross sub-buffers, and so will any new nested event that happens, updating the before stamp is useless, and could even introduce new race conditions. The first event on a sub-buffer simply uses the sub-buffer's timestamp and keeps a "delta" of zero. The "before_stamp" and "write_stamp" are not used in the algorithm in this case. There's no reason to try to fix the before_stamp when this happens. As a bonus, it removes a cmpxchg() when crossing sub-buffers! Link: https://lore.kernel.org/linux-trace-kernel/20231211114420.36dde01b@gandalf.… Cc: stable(a)vger.kernel.org Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Fixes: a389d86f7fd09 ("ring-buffer: Have nested events still record running time stamp") Reviewed-by: Masami Hiramatsu (Google) <mhiramat(a)kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/ring_buffer.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index dcd47895b424..c7abcc215fe2 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3607,14 +3607,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, /* See if we shot pass the end of this buffer page */ if (unlikely(write > BUF_PAGE_SIZE)) { - /* before and after may now different, fix it up*/ - b_ok = rb_time_read(&cpu_buffer->before_stamp, &info->before); - a_ok = rb_time_read(&cpu_buffer->write_stamp, &info->after); - if (a_ok && b_ok && info->before != info->after) - (void)rb_time_cmpxchg(&cpu_buffer->before_stamp, - info->before, info->after); - if (a_ok && b_ok) - check_buffer(cpu_buffer, info, CHECK_FULL_PAGE); + check_buffer(cpu_buffer, info, CHECK_FULL_PAGE); return rb_move_tail(cpu_buffer, tail, info); } -- 2.42.0

1 year, 5 months

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[for-linus][PATCH 05/15] tracing: Update snapshot buffer on resize if it is allocated

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> The snapshot buffer is to mimic the main buffer so that when a snapshot is needed, the snapshot and main buffer are swapped. When the snapshot buffer is allocated, it is set to the minimal size that the ring buffer may be at and still functional. When it is allocated it becomes the same size as the main ring buffer, and when the main ring buffer changes in size, it should do. Currently, the resize only updates the snapshot buffer if it's used by the current tracer (ie. the preemptirqsoff tracer). But it needs to be updated anytime it is allocated. When changing the size of the main buffer, instead of looking to see if the current tracer is utilizing the snapshot buffer, just check if it is allocated to know if it should be updated or not. Also fix typo in comment just above the code change. Link: https://lore.kernel.org/linux-trace-kernel/20231210225447.48476a6a@rorschac… Cc: stable(a)vger.kernel.org Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Fixes: ad909e21bbe69 ("tracing: Add internal tracing_snapshot() functions") Reviewed-by: Masami Hiramatsu (Google) <mhiramat(a)kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/trace.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index aa8f99f3e5de..6c79548f9574 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6348,7 +6348,7 @@ static int __tracing_resize_ring_buffer(struct trace_array *tr, if (!tr->array_buffer.buffer) return 0; - /* Do not allow tracing while resizng ring buffer */ + /* Do not allow tracing while resizing ring buffer */ tracing_stop_tr(tr); ret = ring_buffer_resize(tr->array_buffer.buffer, size, cpu); @@ -6356,7 +6356,7 @@ static int __tracing_resize_ring_buffer(struct trace_array *tr, goto out_start; #ifdef CONFIG_TRACER_MAX_TRACE - if (!tr->current_trace->use_max_tr) + if (!tr->allocated_snapshot) goto out; ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu); -- 2.42.0

1 year, 5 months

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[for-linus][PATCH 04/15] ring-buffer: Fix memory leak of free page

by Steven Rostedt

From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Reading the ring buffer does a swap of a sub-buffer within the ring buffer with a empty sub-buffer. This allows the reader to have full access to the content of the sub-buffer that was swapped out without having to worry about contention with the writer. The readers call ring_buffer_alloc_read_page() to allocate a page that will be used to swap with the ring buffer. When the code is finished with the reader page, it calls ring_buffer_free_read_page(). Instead of freeing the page, it stores it as a spare. Then next call to ring_buffer_alloc_read_page() will return this spare instead of calling into the memory management system to allocate a new page. Unfortunately, on freeing of the ring buffer, this spare page is not freed, and causes a memory leak. Link: https://lore.kernel.org/linux-trace-kernel/20231210221250.7b9cc83c@rorschac… Cc: stable(a)vger.kernel.org Cc: Mark Rutland <mark.rutland(a)arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers(a)efficios.com> Fixes: 73a757e63114d ("ring-buffer: Return reader page back into existing ring buffer") Acked-by: Masami Hiramatsu (Google) <mhiramat(a)kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- kernel/trace/ring_buffer.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index b8986f82eccf..dcd47895b424 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1787,6 +1787,8 @@ static void rb_free_cpu_buffer(struct ring_buffer_per_cpu *cpu_buffer) free_buffer_page(bpage); } + free_page((unsigned long)cpu_buffer->free_page); + kfree(cpu_buffer); } -- 2.42.0

1 year, 5 months

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