usb gadgetfs EFAULT error bugfix #299

oandrew · 2016-06-22T12:46:52Z

copy_to_iter() returns number of bytes copied

Fix checkpatch errors: ERROR: else should follow close brace '}' torvalds#121: FILE: drivers/tty/serial/cpm_uart/cpm_uart_cpm2.c:121: + } + else WARNING: line over 80 characters torvalds#150: FILE: drivers/tty/serial/cpm_uart/cpm_uart_cpm2.c:150: + pinfo->tx_fifosize), (void __force *)pinfo->mem_addr, WARNING: Block comments should align the * on each line torvalds#66: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:66: + * Check, if transmit buffers are processed +*/ WARNING: braces {} are not necessary for any arm of this statement torvalds#170: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:170: + if (IS_SMC(pinfo)) { [...] + } else { [...] WARNING: labels should not be indented torvalds#292: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:292: + error_return: ERROR: code indent should use tabs where possible torvalds#299: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:299: +^I^I BD_SC_OV | BD_SC_ID);$ WARNING: labels should not be indented torvalds#319: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:319: + handle_error: WARNING: line over 80 characters torvalds#423: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:423: + setbits32(&pinfo->sccp->scc_gsmrl, (SCC_GSMRL_ENR | SCC_GSMRL_ENT)); ERROR: space required before the open parenthesis '(' torvalds#451: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:451: + while(!cpm_uart_tx_empty(port)) { WARNING: Missing a blank line after declarations torvalds#462: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:462: + smc_t __iomem *smcp = pinfo->smcp; + clrbits16(&smcp->smc_smcmr, SMCMR_REN | SMCMR_TEN); WARNING: line over 80 characters torvalds#466: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:466: + clrbits32(&sccp->scc_gsmrl, SCC_GSMRL_ENR | SCC_GSMRL_ENT); WARNING: Missing a blank line after declarations torvalds#466: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:466: + scc_t __iomem *sccp = pinfo->sccp; + clrbits32(&sccp->scc_gsmrl, SCC_GSMRL_ENR | SCC_GSMRL_ENT); ERROR: code indent should use tabs where possible torvalds#484: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:484: + struct ktermios *termios,$ WARNING: please, no spaces at the start of a line torvalds#484: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:484: + struct ktermios *termios,$ ERROR: code indent should use tabs where possible torvalds#485: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:485: + struct ktermios *old)$ WARNING: please, no spaces at the start of a line torvalds#485: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:485: + struct ktermios *old)$ WARNING: line over 80 characters torvalds#624: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:624: + /* Output in *one* operation, so we don't interrupt RX/TX if they WARNING: Block comments use a trailing */ on a separate line torvalds#625: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:625: + * were already enabled. */ WARNING: line over 80 characters torvalds#629: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:629: + out_be16(&pinfo->sccup->scc_genscc.scc_mrblr, pinfo->rx_fifosize); WARNING: line over 80 characters torvalds#773: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:773: + mem_addr = pinfo->mem_addr + L1_CACHE_ALIGN(pinfo->rx_nrfifos * pinfo->rx_fifosize); ERROR: code indent should use tabs where possible torvalds#797: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:797: +^I (u8 __iomem *)pinfo->rx_bd_base - DPRAM_BASE);$ ERROR: code indent should use tabs where possible torvalds#799: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:799: +^I (u8 __iomem *)pinfo->tx_bd_base - DPRAM_BASE);$ ERROR: code indent should use tabs where possible torvalds#836: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:836: +^I SCC_GSMRL_MODE_UART | SCC_GSMRL_TDCR_16 | SCC_GSMRL_RDCR_16);$ ERROR: code indent should use tabs where possible torvalds#859: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:859: +^I (u8 __iomem *)pinfo->rx_bd_base - DPRAM_BASE);$ ERROR: code indent should use tabs where possible torvalds#861: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:861: +^I (u8 __iomem *)pinfo->tx_bd_base - DPRAM_BASE);$ WARNING: space prohibited between function name and open parenthesis '(' torvalds#866: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:866: +#if defined (CONFIG_I2C_SPI_SMC1_UCODE_PATCH) WARNING: line over 80 characters torvalds#921: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:921: + clrbits32(&pinfo->sccp->scc_gsmrl, SCC_GSMRL_ENR | SCC_GSMRL_ENT); WARNING: Missing a blank line after declarations torvalds#462: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:462: + smc_t __iomem *smcp = pinfo->smcp; + clrbits16(&smcp->smc_smcmr, WARNING: Missing a blank line after declarations torvalds#467: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:467: + scc_t __iomem *sccp = pinfo->sccp; + clrbits32(&sccp->scc_gsmrl, ERROR: code indent should use tabs where possible torvalds#1151: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1151: + struct uart_cpm_port *pinfo)$ WARNING: please, no spaces at the start of a line torvalds#1151: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1151: + struct uart_cpm_port *pinfo)$ ERROR: "(foo*)" should be "(foo *)" #1161: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1161: + struct clk *clk = clk_get(NULL, (const char*)data); WARNING: Missing a blank line after declarations #1162: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1162: + struct clk *clk = clk_get(NULL, (const char*)data); + if (!IS_ERR(clk)) ERROR: code indent should use tabs where possible #1169: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1169: +^I^I^I "fsl,cpm-brg property.\n", np);$ ERROR: code indent should use tabs where possible #1178: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1178: +^I^I "fsl,cpm-command property.\n", np);$ ERROR: code indent should use tabs where possible #1192: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1192: WARNING: braces {} are not necessary for any arm of this statement #1279: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1279: + if (unlikely(nolock)) { [...] + } else { [...] WARNING: braces {} are not necessary for any arm of this statement #1287: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1287: + if (unlikely(nolock)) { [...] + } else { [...] WARNING: line over 80 characters #1354: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1354: + clrbits32(&pinfo->sccp->scc_gsmrl, SCC_GSMRL_ENR | SCC_GSMRL_ENT); ERROR: Macros with complex values should be enclosed in parentheses #1394: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1394: +#define CPM_UART_CONSOLE &cpm_scc_uart_console WARNING: Missing a blank line after declarations #1437: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1437: + struct uart_cpm_port *pinfo = platform_get_drvdata(ofdev); + return uart_remove_one_port(&cpm_reg, &pinfo->port); WARNING: please, no spaces at the start of a line #1464: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1464: + };$ WARNING: Missing a blank line after declarations #1469: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1469: + int ret = uart_register_driver(&cpm_reg); + if (ret) WARNING: Missing a blank line after declarations torvalds#1062: FILE: drivers/tty/serial/cpm_uart/cpm_uart_core.c:1062: + int i; + volatile cbd_t *bdp; ERROR: "foo * bar" should be "foo *bar" torvalds#19: FILE: drivers/tty/serial/cpm_uart/cpm_uart_cpm1.h:19: +static inline void cpm_set_scc_fcr(scc_uart_t __iomem * sup) ERROR: "foo * bar" should be "foo *bar" torvalds#25: FILE: drivers/tty/serial/cpm_uart/cpm_uart_cpm1.h:25: +static inline void cpm_set_smc_fcr(smc_uart_t __iomem * up) WARNING: Improper SPDX comment style for 'drivers/tty/serial/cpm_uart/cpm_uart.h', please use '/*' instead #1: FILE: drivers/tty/serial/cpm_uart/cpm_uart.h:1: +// SPDX-License-Identifier: GPL-2.0 WARNING: Missing or malformed SPDX-License-Identifier tag in line 1 #1: FILE: drivers/tty/serial/cpm_uart/cpm_uart.h:1: +// SPDX-License-Identifier: GPL-2.0 WARNING: Block comments use * on subsequent lines torvalds#106: FILE: drivers/tty/serial/cpm_uart/cpm_uart.h:106: +/* + virtual to phys transtalion ERROR: code indent should use tabs where possible torvalds#109: FILE: drivers/tty/serial/cpm_uart/cpm_uart.h:109: + struct uart_cpm_port *pinfo)$ WARNING: please, no spaces at the start of a line torvalds#109: FILE: drivers/tty/serial/cpm_uart/cpm_uart.h:109: + struct uart_cpm_port *pinfo)$ ERROR: code indent should use tabs where possible torvalds#125: FILE: drivers/tty/serial/cpm_uart/cpm_uart.h:125: + struct uart_cpm_port *pinfo)$ WARNING: please, no spaces at the start of a line torvalds#125: FILE: drivers/tty/serial/cpm_uart/cpm_uart.h:125: + struct uart_cpm_port *pinfo)$ Signed-off-by: Enrico Weigelt <info@metux.net>

At the time being, PPC32 has Classical BPF support. The test_bpf module exhibits some failure: test_bpf: torvalds#298 LD_IND byte frag jited:1 ret 202 != 66 FAIL (1 times) test_bpf: torvalds#299 LD_IND halfword frag jited:1 ret 51958 != 17220 FAIL (1 times) test_bpf: torvalds#301 LD_IND halfword mixed head/frag jited:1 ret 51958 != 1305 FAIL (1 times) test_bpf: torvalds#303 LD_ABS byte frag jited:1 ret 202 != 66 FAIL (1 times) test_bpf: torvalds#304 LD_ABS halfword frag jited:1 ret 51958 != 17220 FAIL (1 times) test_bpf: torvalds#306 LD_ABS halfword mixed head/frag jited:1 ret 51958 != 1305 FAIL (1 times) test_bpf: Summary: 371 PASSED, 7 FAILED, [119/366 JIT'ed] Fixing this is not worth the effort. Instead, remove support for classical BPF and prepare for adding Extended BPF support instead. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

commit 1b5f1c3 upstream. In register_synth_event(), if set_synth_event_print_fmt() failed, then both trace_remove_event_call() and unregister_trace_event() will be called, which means the trace_event_call will call __unregister_trace_event() twice. As the result, the second unregister will causes the wild-memory-access. register_synth_event set_synth_event_print_fmt failed trace_remove_event_call event_remove if call->event.funcs then __unregister_trace_event (first call) unregister_trace_event __unregister_trace_event (second call) Fix the bug by avoiding to call the second __unregister_trace_event() by checking if the first one is called. general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN PTI KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127] CPU: 0 PID: 3807 Comm: modprobe Not tainted 6.1.0-rc1-00186-g76f33a7eedb4 torvalds#299 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 RIP: 0010:unregister_trace_event+0x6e/0x280 Code: 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 0e 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 63 08 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 e2 01 00 00 49 89 2c 24 48 85 ed 74 28 e8 7a 9b RSP: 0018:ffff88810413f370 EFLAGS: 00010a06 RAX: dffffc0000000000 RBX: ffff888105d050b0 RCX: 0000000000000000 RDX: 1bd5a00000000024 RSI: ffff888119e276e0 RDI: ffffffff835a8b20 RBP: dead000000000100 R08: 0000000000000000 R09: fffffbfff0913481 R10: ffffffff8489a407 R11: fffffbfff0913480 R12: dead000000000122 R13: ffff888105d050b8 R14: 0000000000000000 R15: ffff888105d05028 FS: 00007f7823e8d540(0000) GS:ffff888119e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7823e7ebec CR3: 000000010a058002 CR4: 0000000000330ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __create_synth_event+0x1e37/0x1eb0 create_or_delete_synth_event+0x110/0x250 synth_event_run_command+0x2f/0x110 test_gen_synth_cmd+0x170/0x2eb [synth_event_gen_test] synth_event_gen_test_init+0x76/0x9bc [synth_event_gen_test] do_one_initcall+0xdb/0x480 do_init_module+0x1cf/0x680 load_module+0x6a50/0x70a0 __do_sys_finit_module+0x12f/0x1c0 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Link: https://lkml.kernel.org/r/20221117012346.22647-3-shangxiaojing@huawei.com Fixes: 4b14793 ("tracing: Add support for 'synthetic' events") Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com> Cc: stable@vger.kernel.org Cc: <mhiramat@kernel.org> Cc: <zanussi@kernel.org> Cc: <fengguang.wu@intel.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In register_synth_event(), if set_synth_event_print_fmt() failed, then both trace_remove_event_call() and unregister_trace_event() will be called, which means the trace_event_call will call __unregister_trace_event() twice. As the result, the second unregister will causes the wild-memory-access. register_synth_event set_synth_event_print_fmt failed trace_remove_event_call event_remove if call->event.funcs then __unregister_trace_event (first call) unregister_trace_event __unregister_trace_event (second call) Fix the bug by avoiding to call the second __unregister_trace_event() by checking if the first one is called. general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN PTI KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127] CPU: 0 PID: 3807 Comm: modprobe Not tainted 6.1.0-rc1-00186-g76f33a7eedb4 torvalds#299 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b3f840-prebuilt.qemu.org 04/01/2014 RIP: 0010:unregister_trace_event+0x6e/0x280 Code: 00 fc ff df 4c 89 ea 48 c1 ea 03 80 3c 02 00 0f 85 0e 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 63 08 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 e2 01 00 00 49 89 2c 24 48 85 ed 74 28 e8 7a 9b RSP: 0018:ffff88810413f370 EFLAGS: 00010a06 RAX: dffffc0000000000 RBX: ffff888105d050b0 RCX: 0000000000000000 RDX: 1bd5a00000000024 RSI: ffff888119e276e0 RDI: ffffffff835a8b20 RBP: dead000000000100 R08: 0000000000000000 R09: fffffbfff0913481 R10: ffffffff8489a407 R11: fffffbfff0913480 R12: dead000000000122 R13: ffff888105d050b8 R14: 0000000000000000 R15: ffff888105d05028 FS: 00007f7823e8d540(0000) GS:ffff888119e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7823e7ebec CR3: 000000010a058002 CR4: 0000000000330ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __create_synth_event+0x1e37/0x1eb0 create_or_delete_synth_event+0x110/0x250 synth_event_run_command+0x2f/0x110 test_gen_synth_cmd+0x170/0x2eb [synth_event_gen_test] synth_event_gen_test_init+0x76/0x9bc [synth_event_gen_test] do_one_initcall+0xdb/0x480 do_init_module+0x1cf/0x680 load_module+0x6a50/0x70a0 __do_sys_finit_module+0x12f/0x1c0 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd Link: https://lkml.kernel.org/r/20221117012346.22647-3-shangxiaojing@huawei.com Fixes: 4b14793 ("tracing: Add support for 'synthetic' events") Signed-off-by: Shang XiaoJing <shangxiaojing@huawei.com> Cc: stable@vger.kernel.org Cc: <mhiramat@kernel.org> Cc: <zanussi@kernel.org> Cc: <fengguang.wu@intel.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

userfaultfd_move() checks whether the PTE entry is present or a swap entry. - If the PTE entry is present, move_present_pte() handles folio migration by setting: src_folio->index = linear_page_index(dst_vma, dst_addr); - If the PTE entry is a swap entry, move_swap_pte() simply copies the PTE to the new dst_addr. This approach is incorrect because even if the PTE is a swap entry, it can still reference a folio that remains in the swap cache. If do_swap_page() is triggered, it may locate the folio in the swap cache. However, during add_rmap operations, a kernel panic can occur due to: page_pgoff(folio, page) != linear_page_index(vma, address) $./a.out > /dev/null [ 13.336953] page: refcount:6 mapcount:1 mapping:00000000f43db19c index:0xffffaf150 pfn:0x4667c [ 13.337520] head: order:2 mapcount:1 entire_mapcount:0 nr_pages_mapped:1 pincount:0 [ 13.337716] memcg:ffff00000405f000 [ 13.337849] anon flags: 0x3fffc0000020459(locked|uptodate|dirty|owner_priv_1|head|swapbacked|node=0|zone=0|lastcpupid=0xffff) [ 13.338630] raw: 03fffc0000020459 ffff80008507b538 ffff80008507b538 ffff000006260361 [ 13.338831] raw: 0000000ffffaf150 0000000000004000 0000000600000000 ffff00000405f000 [ 13.339031] head: 03fffc0000020459 ffff80008507b538 ffff80008507b538 ffff000006260361 [ 13.339204] head: 0000000ffffaf150 0000000000004000 0000000600000000 ffff00000405f000 [ 13.339375] head: 03fffc0000000202 fffffdffc0199f01 ffffffff00000000 0000000000000001 [ 13.339546] head: 0000000000000004 0000000000000000 00000000ffffffff 0000000000000000 [ 13.339736] page dumped because: VM_BUG_ON_PAGE(page_pgoff(folio, page) != linear_page_index(vma, address)) [ 13.340190] ------------[ cut here ]------------ [ 13.340316] kernel BUG at mm/rmap.c:1380! [ 13.340683] Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP [ 13.340969] Modules linked in: [ 13.341257] CPU: 1 UID: 0 PID: 107 Comm: a.out Not tainted 6.14.0-rc3-gcf42737e247a-dirty torvalds#299 [ 13.341470] Hardware name: linux,dummy-virt (DT) [ 13.341671] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 13.341815] pc : __page_check_anon_rmap+0xa0/0xb0 [ 13.341920] lr : __page_check_anon_rmap+0xa0/0xb0 [ 13.342018] sp : ffff80008752bb20 [ 13.342093] x29: ffff80008752bb20 x28: fffffdffc0199f00 x27: 0000000000000001 [ 13.342404] x26: 0000000000000000 x25: 0000000000000001 x24: 0000000000000001 [ 13.342575] x23: 0000ffffaf0d0000 x22: 0000ffffaf0d0000 x21: fffffdffc0199f00 [ 13.342731] x20: fffffdffc0199f00 x19: ffff000006210700 x18: 00000000ffffffff [ 13.342881] x17: 6c203d2120296567 x16: 6170202c6f696c6f x15: 662866666f67705f [ 13.343033] x14: 6567617028454741 x13: 2929737365726464 x12: ffff800083728ab0 [ 13.343183] x11: ffff800082996bf8 x10: 0000000000000fd7 x9 : ffff80008011bc40 [ 13.343351] x8 : 0000000000017fe8 x7 : 00000000fffff000 x6 : ffff8000829eebf8 [ 13.343498] x5 : c0000000fffff000 x4 : 0000000000000000 x3 : 0000000000000000 [ 13.343645] x2 : 0000000000000000 x1 : ffff0000062db980 x0 : 000000000000005f [ 13.343876] Call trace: [ 13.344045] __page_check_anon_rmap+0xa0/0xb0 (P) [ 13.344234] folio_add_anon_rmap_ptes+0x22c/0x320 [ 13.344333] do_swap_page+0x1060/0x1400 [ 13.344417] __handle_mm_fault+0x61c/0xbc8 [ 13.344504] handle_mm_fault+0xd8/0x2e8 [ 13.344586] do_page_fault+0x20c/0x770 [ 13.344673] do_translation_fault+0xb4/0xf0 [ 13.344759] do_mem_abort+0x48/0xa0 [ 13.344842] el0_da+0x58/0x130 [ 13.344914] el0t_64_sync_handler+0xc4/0x138 [ 13.345002] el0t_64_sync+0x1ac/0x1b0 [ 13.345208] Code: aa1503e0 f000f801 910f6021 97ff5779 (d4210000) [ 13.345504] ---[ end trace 0000000000000000 ]--- [ 13.345715] note: a.out[107] exited with irqs disabled [ 13.345954] note: a.out[107] exited with preempt_count 2 Fully fixing it would be quite complex, requiring similar handling of folios as done in move_present_pte. For now, a quick solution is to return -EBUSY. I'd like to see others' opinions on whether a full fix is worth pursuing. For anyone interested in reproducing it, the a.out test program is as below, #define _GNU_SOURCE #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/mman.h> #include <sys/ioctl.h> #include <sys/syscall.h> #include <linux/userfaultfd.h> #include <fcntl.h> #include <pthread.h> #include <unistd.h> #include <poll.h> #include <errno.h> #define PAGE_SIZE 4096 #define REGION_SIZE (512 * 1024) #ifndef UFFDIO_MOVE struct uffdio_move { __u64 dst; __u64 src; __u64 len; #define UFFDIO_MOVE_MODE_DONTWAKE ((__u64)1<<0) #define UFFDIO_MOVE_MODE_ALLOW_SRC_HOLES ((__u64)1<<1) __u64 mode; __s64 move; }; #define _UFFDIO_MOVE (0x05) #define UFFDIO_MOVE _IOWR(UFFDIO, _UFFDIO_MOVE, struct uffdio_move) #endif void *src, *dst; int uffd; void *madvise_thread(void *arg) { if (madvise(src, REGION_SIZE, MADV_PAGEOUT) == -1) { perror("madvise MADV_PAGEOUT"); } return NULL; } void *fault_handler_thread(void *arg) { struct uffd_msg msg; struct uffdio_move move; struct pollfd pollfd = { .fd = uffd, .events = POLLIN }; pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL); pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, NULL); while (1) { if (poll(&pollfd, 1, -1) == -1) { perror("poll"); exit(EXIT_FAILURE); } if (read(uffd, &msg, sizeof(msg)) <= 0) { perror("read"); exit(EXIT_FAILURE); } if (msg.event != UFFD_EVENT_PAGEFAULT) { fprintf(stderr, "Unexpected event\n"); exit(EXIT_FAILURE); } move.src = (unsigned long)src + (msg.arg.pagefault.address - (unsigned long)dst); move.dst = msg.arg.pagefault.address & ~(PAGE_SIZE - 1); move.len = PAGE_SIZE; move.mode = 0; if (ioctl(uffd, UFFDIO_MOVE, &move) == -1) { perror("UFFDIO_MOVE"); exit(EXIT_FAILURE); } } return NULL; } int main() { again: pthread_t thr, madv_thr; struct uffdio_api uffdio_api = { .api = UFFD_API, .features = 0 }; struct uffdio_register uffdio_register; src = mmap(NULL, REGION_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (src == MAP_FAILED) { perror("mmap src"); exit(EXIT_FAILURE); } memset(src, 1, REGION_SIZE); dst = mmap(NULL, REGION_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if (dst == MAP_FAILED) { perror("mmap dst"); exit(EXIT_FAILURE); } uffd = syscall(SYS_userfaultfd, O_CLOEXEC | O_NONBLOCK); if (uffd == -1) { perror("userfaultfd"); exit(EXIT_FAILURE); } if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1) { perror("UFFDIO_API"); exit(EXIT_FAILURE); } uffdio_register.range.start = (unsigned long)dst; uffdio_register.range.len = REGION_SIZE; uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING; if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) { perror("UFFDIO_REGISTER"); exit(EXIT_FAILURE); } if (pthread_create(&madv_thr, NULL, madvise_thread, NULL) != 0) { perror("pthread_create madvise_thread"); exit(EXIT_FAILURE); } if (pthread_create(&thr, NULL, fault_handler_thread, NULL) != 0) { perror("pthread_create fault_handler_thread"); exit(EXIT_FAILURE); } for (size_t i = 0; i < REGION_SIZE; i += PAGE_SIZE) { char val = ((char *)dst)[i]; printf("Accessing dst at offset %zu, value: %d\n", i, val); } pthread_join(madv_thr, NULL); pthread_cancel(thr); pthread_join(thr, NULL); munmap(src, REGION_SIZE); munmap(dst, REGION_SIZE); close(uffd); goto again; return 0; } As long as you enable mTHP (which likely increases the residency time of swapcache), you can reproduce the issue within a few seconds. But I guess the same race condition also exists with small folios. Fixes: adef440 ("userfaultfd: UFFDIO_MOVE uABI") Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Brian Geffon <bgeffon@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lokesh Gidra <lokeshgidra@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Nicolas Geoffray <ngeoffray@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Barry Song <v-songbaohua@oppo.com>

usb gadgetfs EFAULT error bugfix

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oandrew closed this Jun 22, 2016

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usb gadgetfs EFAULT error bugfix #299

usb gadgetfs EFAULT error bugfix #299

oandrew commented Jun 22, 2016

usb gadgetfs EFAULT error bugfix #299

usb gadgetfs EFAULT error bugfix #299

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oandrew commented Jun 22, 2016