Messages in this thread | | | From | Vicente Bergas <> | Date | Tue, 4 Sep 2018 18:00:42 +0200 | Subject | Re: [PATCH v2] f2fs: fix to avoid NULL pointer dereference on se->discard_map |
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On Tue, Sep 4, 2018 at 5:45 PM, Chao Yu <chao@kernel.org> wrote: > On 2018/9/4 23:25, Vicente Bergas wrote: >> On Mon, Sep 3, 2018 at 9:52 PM, Chao Yu <chao@kernel.org> wrote: >>> From: Chao Yu <yuchao0@huawei.com> >>> >>> https://nam01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.kernel.org%2Fshow_bug.cgi%3Fid%3D200951&data=02%7C01%7C%7Cc2be7ee866b04268e69f08d6127aa973%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636716715374991374&sdata=E%2Boli5wWbe97f3QCdmAiIIZPEMInd9u221ldtVDqvtA%3D&reserved=0 >>> >>> These is a NULL pointer dereference issue reported in bugzilla: >>> >>> Hi, >>> in the setup there is a SATA SSD connected to a SATA-to-USB bridge. >>> >>> The disc is "Samsung SSD 850 PRO 256G" which supports TRIM. >>> There are four partitions: >>> sda1: FAT /boot >>> sda2: F2FS / >>> sda3: F2FS /home >>> sda4: F2FS >>> >>> The bridge is ASMT1153e which uses the "uas" driver. >>> There is no TRIM pass-through, so, when mounting it reports: >>> mounting with "discard" option, but the device does not support discard >>> >>> The USB host is USB3.0 and UASP capable. It is the one on RK3399. >>> >>> Given this everything works fine, except there is no TRIM support. >>> >>> In order to enable TRIM a new UDEV rule is added [1]: >>> /etc/udev/rules.d/10-sata-bridge-trim.rules: >>> ACTION=="add|change", ATTRS{idVendor}=="174c", ATTRS{idProduct}=="55aa", SUBSYSTEM=="scsi_disk", ATTR{provisioning_mode}="unmap" >>> After reboot any F2FS write hangs forever and dmesg reports: >>> Unable to handle kernel NULL pointer dereference >>> >>> Also tested on a x86_64 system: works fine even with TRIM enabled. >>> same disc >>> same bridge >>> different usb host controller >>> different cpu architecture >>> not root filesystem >>> >>> Regards, >>> Vicenç. >>> >>> [1] Post #5 in https://nam01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbbs.archlinux.org%2Fviewtopic.php%3Fid%3D236280&data=02%7C01%7C%7Cc2be7ee866b04268e69f08d6127aa973%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636716715374991374&sdata=tLP2J%2BL2MPDnqbLm1JcmJ7HfM%2F9j%2F0xc2MET2QSAjVE%3D&reserved=0 >>> >>> Unable to handle kernel NULL pointer dereference at virtual address 000000000000003e >>> Mem abort info: >>> ESR = 0x96000004 >>> Exception class = DABT (current EL), IL = 32 bits >>> SET = 0, FnV = 0 >>> EA = 0, S1PTW = 0 >>> Data abort info: >>> ISV = 0, ISS = 0x00000004 >>> CM = 0, WnR = 0 >>> user pgtable: 4k pages, 48-bit VAs, pgdp = 00000000626e3122 >>> [000000000000003e] pgd=0000000000000000 >>> Internal error: Oops: 96000004 [#1] SMP >>> Modules linked in: overlay snd_soc_hdmi_codec rc_cec dw_hdmi_i2s_audio dw_hdmi_cec snd_soc_simple_card snd_soc_simple_card_utils snd_soc_rockchip_i2s rockchip_rga snd_soc_rockchip_pcm rockchipdrm videobuf2_dma_sg v4l2_mem2mem rtc_rk808 videobuf2_memops analogix_dp videobuf2_v4l2 videobuf2_common dw_hdmi dw_wdt cec rc_core videodev drm_kms_helper media drm rockchip_thermal rockchip_saradc realtek drm_panel_orientation_quirks syscopyarea sysfillrect sysimgblt fb_sys_fops dwmac_rk stmmac_platform stmmac pwm_bl squashfs loop crypto_user gpio_keys hid_kensington >>> CPU: 5 PID: 957 Comm: nvim Not tainted 4.19.0-rc1-1-ARCH #1 >>> Hardware name: Sapphire-RK3399 Board (DT) >>> pstate: 00000005 (nzcv daif -PAN -UAO) >>> pc : update_sit_entry+0x304/0x4b0 >>> lr : update_sit_entry+0x108/0x4b0 >>> sp : ffff00000ca13bd0 >>> x29: ffff00000ca13bd0 x28: 000000000000003e >>> x27: 0000000000000020 x26: 0000000000080000 >>> x25: 0000000000000048 x24: ffff8000ebb85cf8 >>> x23: 0000000000000253 x22: 00000000ffffffff >>> x21: 00000000000535f2 x20: 00000000ffffffdf >>> x19: ffff8000eb9e6800 x18: ffff8000eb9e6be8 >>> x17: 0000000007ce6926 x16: 000000001c83ffa8 >>> x15: 0000000000000000 x14: ffff8000f602df90 >>> x13: 0000000000000006 x12: 0000000000000040 >>> x11: 0000000000000228 x10: 0000000000000000 >>> x9 : 0000000000000000 x8 : 0000000000000000 >>> x7 : 00000000000535f2 x6 : ffff8000ebff3440 >>> x5 : ffff8000ebff3440 x4 : ffff8000ebe3a6c8 >>> x3 : 00000000ffffffff x2 : 0000000000000020 >>> x1 : 0000000000000000 x0 : ffff8000eb9e5800 >>> Process nvim (pid: 957, stack limit = 0x0000000063a78320) >>> Call trace: >>> update_sit_entry+0x304/0x4b0 >>> f2fs_invalidate_blocks+0x98/0x140 >>> truncate_node+0x90/0x400 >>> f2fs_remove_inode_page+0xe8/0x340 >>> f2fs_evict_inode+0x2b0/0x408 >>> evict+0xe0/0x1e0 >>> iput+0x160/0x260 >>> do_unlinkat+0x214/0x298 >>> __arm64_sys_unlinkat+0x3c/0x68 >>> el0_svc_handler+0x94/0x118 >>> el0_svc+0x8/0xc >>> Code: f9400800 b9488400 36080140 f9400f01 (387c4820) >>> ---[ end trace a0f21a307118c477 ]--- >>> >>> The reason is it is possible to enable discard flag on block queue via >>> UDEV, but during mount, f2fs will initialize se->discard_map only if >>> this flag is set, once the flag is set after mount, f2fs may dereference >>> NULL pointer on se->discard_map. >>> >>> So this patch does below changes to fix this issue: >>> - initialize and update se->discard_map all the time. >>> - don't clear DISCARD option if device has no QUEUE_FLAG_DISCARD flag >>> during mount. >>> - don't issue small discard on zoned block device. >>> - introduce some functions to enhance the readability. >>> >>> Signed-off-by: Chao Yu <yuchao0@huawei.com> >>> --- >>> v2: >>> - rebase to last dev branch. >>> fs/f2fs/debug.c | 3 +-- >>> fs/f2fs/f2fs.h | 15 ++++++++--- >>> fs/f2fs/file.c | 2 +- >>> fs/f2fs/segment.c | 65 ++++++++++++++++++++--------------------------- >>> fs/f2fs/super.c | 16 +++--------- >>> 5 files changed, 46 insertions(+), 55 deletions(-) >>> >>> diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c >>> index 214a968962a1..ebe649d9793c 100644 >>> --- a/fs/f2fs/debug.c >>> +++ b/fs/f2fs/debug.c >>> @@ -190,8 +190,7 @@ static void update_mem_info(struct f2fs_sb_info *sbi) >>> si->base_mem += MAIN_SEGS(sbi) * sizeof(struct seg_entry); >>> si->base_mem += f2fs_bitmap_size(MAIN_SEGS(sbi)); >>> si->base_mem += 2 * SIT_VBLOCK_MAP_SIZE * MAIN_SEGS(sbi); >>> - if (f2fs_discard_en(sbi)) >>> - si->base_mem += SIT_VBLOCK_MAP_SIZE * MAIN_SEGS(sbi); >>> + si->base_mem += SIT_VBLOCK_MAP_SIZE * MAIN_SEGS(sbi); >>> si->base_mem += SIT_VBLOCK_MAP_SIZE; >>> if (sbi->segs_per_sec > 1) >>> si->base_mem += MAIN_SECS(sbi) * sizeof(struct sec_entry); >>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >>> index 96bde026636f..b575ec75ef87 100644 >>> --- a/fs/f2fs/f2fs.h >>> +++ b/fs/f2fs/f2fs.h >>> @@ -3399,11 +3399,20 @@ static inline int get_blkz_type(struct f2fs_sb_info *sbi, >>> } >>> #endif >>> >>> -static inline bool f2fs_discard_en(struct f2fs_sb_info *sbi) >>> +static inline bool f2fs_hw_should_discard(struct f2fs_sb_info *sbi) >>> { >>> - struct request_queue *q = bdev_get_queue(sbi->sb->s_bdev); >>> + return f2fs_sb_has_blkzoned(sbi->sb); >>> +} >>> >>> - return blk_queue_discard(q) || f2fs_sb_has_blkzoned(sbi->sb); >>> +static inline bool f2fs_hw_support_discard(struct f2fs_sb_info *sbi) >>> +{ >>> + return blk_queue_discard(bdev_get_queue(sbi->sb->s_bdev)); >>> +} >>> + >>> +static inline bool f2fs_realtime_discard_enable(struct f2fs_sb_info *sbi) >>> +{ >>> + return (test_opt(sbi, DISCARD) && f2fs_hw_support_discard(sbi)) || >>> + f2fs_hw_should_discard(sbi); >>> } >>> >>> static inline void set_opt_mode(struct f2fs_sb_info *sbi, unsigned int mt) >>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >>> index 5474aaa274b9..ca66b3eb197a 100644 >>> --- a/fs/f2fs/file.c >>> +++ b/fs/f2fs/file.c >>> @@ -1978,7 +1978,7 @@ static int f2fs_ioc_fitrim(struct file *filp, unsigned long arg) >>> if (!capable(CAP_SYS_ADMIN)) >>> return -EPERM; >>> >>> - if (!blk_queue_discard(q)) >>> + if (!f2fs_hw_support_discard(F2FS_SB(sb))) >>> return -EOPNOTSUPP; >>> >>> if (copy_from_user(&range, (struct fstrim_range __user *)arg, >>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >>> index 30779aaa9dba..c372ff755818 100644 >>> --- a/fs/f2fs/segment.c >>> +++ b/fs/f2fs/segment.c >>> @@ -1725,11 +1725,11 @@ static bool add_discard_addrs(struct f2fs_sb_info *sbi, struct cp_control *cpc, >>> struct list_head *head = &SM_I(sbi)->dcc_info->entry_list; >>> int i; >>> >>> - if (se->valid_blocks == max_blocks || !f2fs_discard_en(sbi)) >>> + if (se->valid_blocks == max_blocks || !f2fs_hw_support_discard(sbi)) >>> return false; >>> >>> if (!force) { >>> - if (!test_opt(sbi, DISCARD) || !se->valid_blocks || >>> + if (!f2fs_realtime_discard_enable(sbi) || !se->valid_blocks || >>> SM_I(sbi)->dcc_info->nr_discards >= >>> SM_I(sbi)->dcc_info->max_discards) >>> return false; >>> @@ -1835,7 +1835,7 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi, >>> dirty_i->nr_dirty[PRE]--; >>> } >>> >>> - if (!test_opt(sbi, DISCARD)) >>> + if (!f2fs_realtime_discard_enable(sbi)) >>> continue; >>> >>> if (force && start >= cpc->trim_start && >>> @@ -2025,8 +2025,7 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del) >>> del = 0; >>> } >>> >>> - if (f2fs_discard_en(sbi) && >>> - !f2fs_test_and_set_bit(offset, se->discard_map)) >>> + if (!f2fs_test_and_set_bit(offset, se->discard_map)) >>> sbi->discard_blks--; >>> >>> /* don't overwrite by SSR to keep node chain */ >>> @@ -2054,8 +2053,7 @@ static void update_sit_entry(struct f2fs_sb_info *sbi, block_t blkaddr, int del) >>> del = 0; >>> } >>> >>> - if (f2fs_discard_en(sbi) && >>> - f2fs_test_and_clear_bit(offset, se->discard_map)) >>> + if (f2fs_test_and_clear_bit(offset, se->discard_map)) >>> sbi->discard_blks++; >>> } >>> if (!f2fs_test_bit(offset, se->ckpt_valid_map)) >>> @@ -2671,7 +2669,7 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range) >>> * discard option. User configuration looks like using runtime discard >>> * or periodic fstrim instead of it. >>> */ >>> - if (test_opt(sbi, DISCARD)) >>> + if (f2fs_realtime_discard_enable(sbi)) >>> goto out; >>> >>> start_block = START_BLOCK(sbi, start_segno); >>> @@ -3762,13 +3760,11 @@ static int build_sit_info(struct f2fs_sb_info *sbi) >>> return -ENOMEM; >>> #endif >>> >>> - if (f2fs_discard_en(sbi)) { >>> - sit_i->sentries[start].discard_map >>> - = f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE, >>> - GFP_KERNEL); >>> - if (!sit_i->sentries[start].discard_map) >>> - return -ENOMEM; >>> - } >>> + sit_i->sentries[start].discard_map >>> + = f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE, >>> + GFP_KERNEL); >>> + if (!sit_i->sentries[start].discard_map) >>> + return -ENOMEM; >>> } >>> >>> sit_i->tmp_map = f2fs_kzalloc(sbi, SIT_VBLOCK_MAP_SIZE, GFP_KERNEL); >>> @@ -3916,18 +3912,16 @@ static int build_sit_entries(struct f2fs_sb_info *sbi) >>> total_node_blocks += se->valid_blocks; >>> >>> /* build discard map only one time */ >>> - if (f2fs_discard_en(sbi)) { >>> - if (is_set_ckpt_flags(sbi, CP_TRIMMED_FLAG)) { >>> - memset(se->discard_map, 0xff, >>> - SIT_VBLOCK_MAP_SIZE); >>> - } else { >>> - memcpy(se->discard_map, >>> - se->cur_valid_map, >>> - SIT_VBLOCK_MAP_SIZE); >>> - sbi->discard_blks += >>> - sbi->blocks_per_seg - >>> - se->valid_blocks; >>> - } >>> + if (is_set_ckpt_flags(sbi, CP_TRIMMED_FLAG)) { >>> + memset(se->discard_map, 0xff, >>> + SIT_VBLOCK_MAP_SIZE); >>> + } else { >>> + memcpy(se->discard_map, >>> + se->cur_valid_map, >>> + SIT_VBLOCK_MAP_SIZE); >>> + sbi->discard_blks += >>> + sbi->blocks_per_seg - >>> + se->valid_blocks; >>> } >>> >>> if (sbi->segs_per_sec > 1) >>> @@ -3965,16 +3959,13 @@ static int build_sit_entries(struct f2fs_sb_info *sbi) >>> if (IS_NODESEG(se->type)) >>> total_node_blocks += se->valid_blocks; >>> >>> - if (f2fs_discard_en(sbi)) { >>> - if (is_set_ckpt_flags(sbi, CP_TRIMMED_FLAG)) { >>> - memset(se->discard_map, 0xff, >>> - SIT_VBLOCK_MAP_SIZE); >>> - } else { >>> - memcpy(se->discard_map, se->cur_valid_map, >>> - SIT_VBLOCK_MAP_SIZE); >>> - sbi->discard_blks += old_valid_blocks; >>> - sbi->discard_blks -= se->valid_blocks; >>> - } >>> + if (is_set_ckpt_flags(sbi, CP_TRIMMED_FLAG)) { >>> + memset(se->discard_map, 0xff, SIT_VBLOCK_MAP_SIZE); >>> + } else { >>> + memcpy(se->discard_map, se->cur_valid_map, >>> + SIT_VBLOCK_MAP_SIZE); >>> + sbi->discard_blks += old_valid_blocks; >>> + sbi->discard_blks -= se->valid_blocks; >>> } >>> >>> if (sbi->segs_per_sec > 1) { >>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c >>> index 53d70b64fea1..5cad0f7687e9 100644 >>> --- a/fs/f2fs/super.c >>> +++ b/fs/f2fs/super.c >>> @@ -360,7 +360,6 @@ static int f2fs_check_quota_options(struct f2fs_sb_info *sbi) >>> static int parse_options(struct super_block *sb, char *options) >>> { >>> struct f2fs_sb_info *sbi = F2FS_SB(sb); >>> - struct request_queue *q; >>> substring_t args[MAX_OPT_ARGS]; >>> char *p, *name; >>> int arg = 0; >>> @@ -415,14 +414,7 @@ static int parse_options(struct super_block *sb, char *options) >>> return -EINVAL; >>> break; >>> case Opt_discard: >>> - q = bdev_get_queue(sb->s_bdev); >>> - if (blk_queue_discard(q)) { >>> - set_opt(sbi, DISCARD); >>> - } else if (!f2fs_sb_has_blkzoned(sb)) { >>> - f2fs_msg(sb, KERN_WARNING, >>> - "mounting with \"discard\" option, but " >>> - "the device does not support discard"); >>> - } >>> + set_opt(sbi, DISCARD); >>> break; >>> case Opt_nodiscard: >>> if (f2fs_sb_has_blkzoned(sb)) { >>> @@ -1032,7 +1024,8 @@ static void f2fs_put_super(struct super_block *sb) >>> /* be sure to wait for any on-going discard commands */ >>> dropped = f2fs_wait_discard_bios(sbi); >>> >>> - if (f2fs_discard_en(sbi) && !sbi->discard_blks && !dropped) { >>> + if ((f2fs_hw_support_discard(sbi) || f2fs_hw_should_discard(sbi)) && >>> + !sbi->discard_blks && !dropped) { >>> struct cp_control cpc = { >>> .reason = CP_UMOUNT | CP_TRIMMED, >>> }; >>> @@ -1399,8 +1392,7 @@ static void default_options(struct f2fs_sb_info *sbi) >>> set_opt(sbi, NOHEAP); >>> sbi->sb->s_flags |= SB_LAZYTIME; >>> set_opt(sbi, FLUSH_MERGE); >>> - if (blk_queue_discard(bdev_get_queue(sbi->sb->s_bdev))) >>> - set_opt(sbi, DISCARD); >>> + set_opt(sbi, DISCARD); >>> if (f2fs_sb_has_blkzoned(sbi->sb)) >>> set_opt_mode(sbi, F2FS_MOUNT_LFS); >>> else >>> -- >>> 2.18.0 >>> >> >> Hi, >> just tested and it works fine: no more segfaults. >> How can i check that TRIM is indeed being used? > > You can check discard trace: > > echo 1 > /sys/kernel/debug/tracing/events/f2fs/f2fs_issue_discard/enable > cat /sys/kernel/debug/tracing/trace_pipe
I confirm that there are discarded blocks in two filesystems: a.- The root filesystem, which had the discard option applied after mount. b.- A non-root filesystem, which had the discard option applied before mount. So, complete success!
Regards, Vicenç.
> > Thanks, > >> >> Tested-by: Vicente Bergas <vicencb@gmail.com> >> >> Regards, >> Vicenç. >>
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